Willis' Astronomical Observations

M42 Pleiades: A trial shot

2012-01-03T05:49:00.000-08:00

This M42, Pleiades (七姊妹星團) was taken with an APM-TMB 105/650 with WO’s FLT flattener in24-11-2011 at Pak Tam Chung, Hong Kong. I didn’t optimize the back focus forthe flattener in present of P2 filter. The performance was good. I need to waitfor clear skies to do the optimization, but the sky in HK is alwaysdisappointing. Maybe I need to use artificial star to do the optimization. Althoughthe distance is not infinity, it gives an approximated back focus adjustment.This can save me some time during field test.

APM-TMB 105/650, FLT, P2, Canon 5DII, HEQ5Pro

ISO 1600, 5 mins x 10

DSS, PS4, cropped

10-12-2011 Total Lunar Eclipse at Hong Kong

2011-12-16T06:52:00.000-08:00

What a wonderful lunar eclipse! This is the first time I imaged the whole total lunar eclipse. I was so luckily that the weather was exceptionally good in Hong Kong. I enjoyed the total lunar eclipse for about six hours! However, due to lack of experience, my photos were not good. I did every in rush. Now after reflection I summarized the reason of these bad photos.

1. I pointed the scope to Jupiter and got it focused with the focusing mask. It is no good to use planets to do focus. They are extended objects, the diffraction spikes are wide. It is hard to make judgment whether it is in focus. It is by all mean pick a bright star to do focusing.

2. My scope was placed inside my car’s boot for an afternoon. I guess the temperature is around 20oC to 23oC that day. However, the average temperature while I took the photos is about 14oC and the lowest temperature was 11oC. I checked the focus at the end of the eclipse by pointing the scope to Sirius. It was out of focus! According to previous testing, the focal shift was about 6x7=42um (6 divisions in electric Feather Touch focuser and each division is about 7um displacement). So I should check the focus regularly, say every 30 mins.

3. During the whole lunar eclipse, the brightness of the moon varies a lot. In my case, I set the ISO to 800, the corresponding shutter speed varies from 1/4000s to 1/10s. In addition, I need to pick different exposures for selections later. Originally I set the interval of the programmable shutter to 1 min. I noticed that I need more exposure for selection in the middle of the imaging. It is luckily that I can still make it by doing bracketing exposures for every time intervals. So it is quite an involving job!

4. The shutter speed would be slow at totality, if the ISO is not high enough. In my case of ISO 800, the shutter speed was down to 1/10s. For tele-photography, one should use high ISO. So get a low noise camera and set high ISO.

My first successful solar mosaic!

2011-05-31T05:54:00.000-07:00

I tried several times, but failed. This is the first time, the image looks decent.
LS80T, DMK21, EQ3Pro, mosaic of 6 panes

26-1-2011 A sunspot with a scar & a big prominence

2011-01-26T01:15:00.000-08:00

There are two sunspots and one of those with a scar. Isn’t it funny? The seeing today is bad. Originally I intended to use TV 5X & DMK 21 to do a high magnification shot, but it sucks because of the bad seeing today. These images are taken with TV 2.5X & DMK21.

LS80T, TV 2.5X, DMK21

19-1-2011 Solar Observation

2011-01-21T06:26:00.000-08:00

The activity is low. Anyway, this is a chance for me to practice solar imaging with this new LS80T. The focal length of the LS80T is 560mm. The CCD size of DMK 41 cannot capture full solar disc in one go. Therefore a drifting approach is needed. In order to align the full disc properly, one needs to select those alignment points which appear in the whole video. Otherwise misalignment or non-uniform brightness will be resulted.

LS80T, DMK41

LS80T, DMK21, TV 2.5X

17-1-2011 lots of proms today

2011-01-17T07:38:00.000-08:00

The sun got lots of prominence and one sunspot today. I tried to image the sunspot at higher magnification. But I cannot make it because I have lessons to go!
Equipment: LS80T, DMK41, DMK21

Browsing around Orion with a small spaceship Tak FS60C

2010-12-31T08:39:00.000-08:00

I used to use my Takahashi FS60C to do visual observations at home. It is a convenient scope for casual lunar & planetary observations. However, I bought a Tak f6.2 flattener for unsound reason, Deep Sky Imaging! It has been hanged around for more than a half year. Two days ago, 28/12/2010, I have a chance to try this little spaceship. The best destination for small spaceship in winter is the good old Orion region. Here are the products.
Takahashi FS60C
Tak FS60C Flattener f6.2
40D
LVI II
350mm guide scope (A modified 9x50 finder scope)
LPS-P2
HEQ5Pro
ISO 800
Dark frame
M42 (6x6mins = 36mins)
Horsehead Nebula (5x6mins + 1x10min = 40mins)

M42 (resized centre crop)

M42 (resized 100% crop)

Horsehead Nebula (resized centre crop)

Horsehead Nebula (resized 100% crop)

The First Light of Lunt LS80THa/PT

2010-12-23T07:48:00.000-08:00

This is the first light of LS80THa/PT. The sun is not active today. Nothing special can be seen… The focal length of LS80T is 560mm, the DMK cannot image the full disc in one go. Luckily the width of the DMK sensor is able to cover full disc, the other shorter direction is being captured by drifting. One can see there is a slight horizontal artifact in the image. I don’t know how to get rid of it.
In general, the scope deliveries uniform images for both visual & photography. The newly equipped pressure tune of LS80THa/PT is gorgeous! It just likes the Feather touch version of etalon tuning. This sophisticated design makes fine Doppler tuning possible.

My First M42

2010-11-07T23:14:00.000-08:00

I started DSI since this summer.

http://willisao.blogspot.com/2010/07/my-first-dsi-m8-m20.html

M8 & M20 are easy targets in the summer. I have seen lots of M42 in Internet. Last night the sky condition was good and enabled me to image my first M42. In the middle of the imaging, LVI complainted several times of loss star! I looked at the sky. The guide star was not covered by clouds. Gosh! The guide scope was fogged! I have no heater. In fact both guide scope & main scope were fogged. I didn’t know when this happened. I have no cleaning kits! This certainly caused loss some contrast & resolution etc. Perhaps there is lots of room for improvement, I am very happy with this image. It marks my first winter DSI this year.
Equinox 80ED

Astrotech Zero Power flattener

40D

LVI II

350mm guide scope (A modified 9x50 finder scope)

LPS-P2

HEQ5 Pro

ISO 800

2x30s, 6x2mins, 2x5mins, 2x10mins = 43mins (Total)

24-10-2010 High Resolution Lunar Mosaic of 29 Pieces

2010-11-02T01:42:00.001-07:00

I've been waited for full moon for more than half year since last encounter!

http://willisao.blogspot.com/2009/12/high-resolution-lunar-mosaic.html

Finally I made it on 24-10-2010!!! This is a resized version. The original size is 5261x4628. I wish I can break the world record one day.

http://www.lunarworldrecord.com/

Best 95% of 100 frames per avi files are stacked. HKT 01:00, 24-10-2010, Moon age 15.9, Equinox 120ED, Baader UV/IR, EQ3Pro, DMK41, Registax 5, PS CS4

The Harvest of Taiwan Star Hunting Trip

2010-07-25T07:19:00.000-07:00

After a week back from Taiwan, I have just finished processing all the raw deep sky objects’ images. As a novice in DSI and an illiterate in processing DSI, I spent extra time to refine the images. Perhaps the quality of the images are average, I learned a lot and received positive feedbacks from other stargazers. The sky in Hehuan Mountain (合歡山) was not as dark as expected. It was much better than the sky of Hong Kong already. There were too many stars in the sky and made me difficult to identify the constellations. Gorgeous! The spectacular Milky Way was engraved in my mind and it was the second time I saw it. I was told that the sky in Australia is extremely dark. The Milky Way is able to cast you a shadow. I have put Tasmania in my vacation list. Hope to visit Tasmania in near future. Anyway, these are my harvest:

M31 Andromeda Galaxy 仙女座大星系: APM-TMB 80/480, AstroTech zero power flattener, Baader LPS-P2, ISO 800, 4x10mins, No flat field, No dark frame

North America Nebula 北美星雲: APM-TMB 80/480, AstroTech zero power flattener, Baader LPS-P2, ISO 800, 6x4mins, No flat field, No dark frame

M13: APM-TMB 80/480, AstroTech zero power flattener, Baader LPS-P2, ISO 800, 9x6mins, No flat field, No dark frame

Double Cluster (NGC884 & NGC869) 雙星團: APM-TMB 80/480, TV 0.8X Reducer/Flattener, Baader LPS-P2, ISO 800, 2x3mins, No flat field, No dark frame

Rho Ophiuchi Nebula 星空調色盤: Canon 135mm f/2.0 @f/2.8, Astronomic CLS clip-filter (CCD version), ISO 800, 10x3mins, No flat field, No dark frame

Sagittarius M8 M20 人馬座天區的礁湖星雲、三裂星雲: Canon 135mm f/2.0 @f/2.8, Astronomic CLS clip-filter (CCD version), ISO 800, 8x3mins, No flat field, No dark frame

Scorpius M6 M7 天蠍座天區的 M6 M7: Canon 135mm f/2.0 @f/2.8, Astronomic CLS clip-filter (CCD version), ISO 800, 10x3mins, No flat field, No dark frame

Summer Triangle 夏天大三角: Tokina 11-16 f/2.8 @16mm & f/4, Astronomic CLS clip-filter (CCD version), ISO 800, 8x3mins, No flat field, No dark frame

Polaris, M31 and Double Cluster 北極星、仙女座大星系、雙星團: Tokina 11-16 f/2.8 @16mm & f/3.5, Astronomic CLS clip-filter (CCD version), ISO 800, 7x3mins, No flat field, No dark frame

Milky Way 銀河: Tokina 11-16 f/2.8 @11mm & f/4, ISO 1600, 30s, No flat field, No dark frame

Equipment list:

APM-TMB 80/480

TV 0.8X Reducer/Flattener

AstroTech Flattener (zero power)

Guide scope (modified Takahashi finder scope)

Canon 40D (Baader modified)

Canon 135mm f/2.0

Tokina 11-16mm f/2.8

HEQ5Pro

LVI I

Baader LPS-P2

Astronomic CLS clip-filter (CCD version)

Unexpected weather of Hehuan mountain

2010-07-13T03:06:00.000-07:00

Totally unexpected! The weather last night was so dramatic!!! It started with rain, lightning & thunder. After the rain stopped, the sky was clear! We ran up to a site called 武嶺 at once. In the middle of setting up the equipment, terrible fog came. Savio & I were punished to stand & wait! In the midnight, the sky was clear again. We started the setting again. There were terrible people around & they used torches!!! Anyway, the sky was unstable until 3:00am. I was on the point of giving up, but finally I got everything work!!!! These are my M31 & Double Cluster! I found that when I use the auto Noise reduction in D40, there is a dark band in the lower part of the images!!! In addition, dews were formed in both the main scope & the guide scope. I don’t have any heater to avoid it. So I can just use an air pump to rectify the problem. It couldn’t be fixed completely anyway! The lucky thing is that it didn’t cross my DSO. Otherwise, it wasted my time. Sometimes we really need some luck to take good photos. When the sky is OK, no people & car making any forms of light pollution, there was a satellite crossing my 10 mins M31 photo. Good grief! Well, I posted both cropped & un-cropped versions here. I will not use the noise reduction function in the coming night, unless I fixed the problem.

APM-TMB 80/480
TV 0.8X
LPS-P2
HEQ5Pro LVI I
M31: ISO 800, 600s, single frame, No flat frame, No dark frame (There was a satellite crossed my photo!!! I will make it again!!!)
Double Cluster: ISO 800, 300s, single frame, No flat frame, No dark frame

Double Cluster: The dark band due to 40D's noise reduction

Double Cluster: Centre Crop

M31

LVI guided stably

Our Equipment

武嶺(3275m)

The daybreak of Hehuan mountain

Taiwan Hehuan Mountain Star Hunting Trip

2010-07-12T03:31:00.000-07:00

Savio and I arrived Hehuan Mountain (合歡山) yesterday. We must express our heartfelt thank to Henry that he helped us to do the transportation and accommodation. In addition, he lent us two HEQ5Pros to us. This is crucial important to us, as the weight we need to ship to Taiwan is much lower. One more point I would like to mention is that we found a Taxi driver to drive us around this week. Originally I want to hire a car and drive by myself, which is always the way I do when I go aboard. However, Savio’s suggest is right! The road in the mountain area is very rugged and difficult to ask for help when needed. So, found a tour guide Taxi driver can save money & convenient. Our base is around the Chingjing Farm (清境農場). Since there are much visitor recently, we stated in 觀星園 http://starry.nantou.com.tw/. The altitude of觀星園is about 2000m. The view of 觀星園is good and leisure. The Birdseye view of 觀星園is great. As the altitude is quite high, we are above the top of low altitude clouds. However, there are still high level clouds above me. Anyway, it should be much better than sea level. Hopefully I can shot some nice photos this trip. It was a long day! Both Savio & I slept for only 2 to 3 hours before we went to Taiwan. So we took a bit more rest before we went to 小風口 and it’s altitude is about 2800m. We don’t have thermometer, but I guess the temperature is below 10 degree. Both Savio and I wore down. As the weather yesterday in the daytime was foggy & haze. We don’t expect too much last night. It turned out that we have occasionally clear skies after 2:00am. It was on and off anyway! Time is limited! When Savio was taking a rest in the Taxi, I took a few Milky Way shot. At about 3:00am, the clear sky suddenly came out & we started to work! Poor me! The sky became bright at about 4:00am and we were running out of time. I am too inexperience & sucked finally!
The photographic detail of the Milky Way is following: Modified Canon 40D Tokina 11-16mm f2.8 @ 11mm f4 ISO1600 30s

Highest altitude Convenient store
On top of low altitude clouds

APM-TMB 80/480, HEQ5Pro

Savio & I at about 2800m and below 10 degree

Milky Way

My first DSI: M8 & M20

2010-07-09T07:54:00.000-07:00

Last week the sky was exceptionally clear. I’ve been waited for clear skies for more than a half year. This was the first time I did DSI. This image was jointly taken with my friend. In fact he did most of the setting and the APM 80/600 and the 5DII were owned by him. The seeing was so so that night and the clouds were just running around and made us lost guiding star several times! We only shot one M8 & M20 before the moonrise. Although we have taken a few M8 & M20, I don’t know how to use DSS. I just use the PS to tune the Level & Curve. Here is the photographic detail:

APM-TMB 80/600
TS flattener (Zero Power)
5D II
LVI I
350mm guide scope (A modified 9x50 finder scope)
LPS-V4
HEQ5Pro
ISO 1600
Single frame (180s)
No flat field and no dark frame
100% crop and 25% resize
4-7-2010

My ND3 has gone! Correct way to used Herschel Wedge

2010-06-07T07:09:00.000-07:00

My ND3 has gone! Today I found out the reason that why there are unknown marks on my Herschel Wedge images since last solar observation in 25/5/2010. The marks on the image would not rotate with the camera. And I found there was no dust on the CCD, the filters and the Herschel Wedge. There were no visible damages in any optical parts. However, the problem was more pronounce in high magnification. Today I detach the ND3 and inspected it under the sun. Gosh! There were cracks on the ND3. I remembered that last time I reversed the order of assembling the Herschel Wedge. The ordering was:

Objective side, ND3, Herschel Wedge, Polarizer or Green continuum, Eyepiece side (WONG!!!)

This ordering terms out to be wrong. My ND3 cannot stand for the heat energy and micro cracks formed! I need to buy a new one now! Dear Herschel Wedge users, don’t repeat my silly fault. The correct ordering should be:

Objective side, Herschel Wedge, ND3, Polarizer or Green continuum, Eyepiece side (RIGHT!!!)

Cracks under strong light

No visible damage under normal light

Unknown marks on the image

24-5-2010 Sun (Active region 1072)

2010-05-24T08:23:00.000-07:00

A long waited blue sky! But the weather forecast in the coming week is bad! Just one day!!!

LS 35T, TV 5X, DMK41, Best 95% of 150 frames

LS 35T, TV 2.5X, DMK41, Best 95% of 150 frames

LS 35T, DMK41, Best 95% of 150 frames

The treasure solar image in 24-4-2010

2010-04-26T07:57:00.001-07:00

The sky in HK is really disappointing! It has been cloudy, foggy and misty for more than 3 months! Even the sun is hardly found during daytime! This is a treasure shot recently!

LS35T, stack of best 95% of 450 frames

2010 Easter Taiwan Trip

2010-04-26T03:55:00.000-07:00

This Easter I went to southern Taiwan for a vacation. I visited Kaohsiung(高雄), Hengchun Peninsula(恆春半島), Szchung River Hot Springs(四重溪溫泉), Kenting(懇丁) etc. This was the first time I did stargazing overseas. However, starting from 1/4/2010 to 7/4/2010, the sky was not cooperating. I took only one photo of the big dipper. During the last night in Taiwan, I drove about 20km from the hotel, Maya House (瑪雅之家), to Lungpan Park (龍盤公園) and Fengchueisha (風吹沙) alone and try my final effort to see if any chance for me. Well the sky was very dark. Nothing can be seen in the rear mirror of my car. The road was dead silent! It is quite scary to do stargazing alone in this situation. Anyway, the sky was covered by clouds! I finally quit!

26-3-2010 Sun (1057 Active Region)

2010-03-26T07:27:00.000-07:00

I just find this organization provides the solar information, including the nomenclature of action regions.
http://www.solarmonitor.org/
http://hesperia.gsfc.nasa.gov/sftheory/questions.htm#AR_numbers
http://www.swpc.noaa.gov/ftpmenu/index.html
Seeing: 3/10
Transparency: 4/10

LS35T, DMK 41
LS35T, DMK 41

LS35T, TV 5X, DMK 41

Equinox 120ED, Herschel Wedge, TV 5X, DMK41

Small scope & big prominence

2010-03-19T08:11:00.000-07:00

The big prominence diminished a bit today.

LS35T

LS35T + TV 5X

The First Light of Herschel Wedge

2010-03-18T09:05:00.000-07:00

Due to the recent poor weather in Hong Kong, my new APM 1.25” Herschel Wedge has been waited in the storeroom for a few days. Although both transparency and seeing were bad today, the sun was awaken! After I used my LS35T to shot the big prominence, I compared the Thousand Oaks Optical Solar Filter Type 2+ & Herschel Wedge. Luckily, the sun has a very small sunspot. It is not obviously showed in my little LS35T. The resolution of LS35T is not high enough to see the detail of the small sunspot. I deliberately used the Oaks Optical Solar Filter Type 2+ & Herschel Wedge on Equinox 120ED respectively. The sun surface showed by Thousand Oaks was quite flat. However, the sun surface showed by Herschel Wedge has details! The color of Herschel wedge is natural and the image is of high contrast compared with Thousand Oaks filter. In terms of safety, I like the Herschel Wedge because if it is taken away, basically one cannot do observation. On the other hands, if a front solar filter is accidentally dropped off, one can still place his or her eyes behind the eyepiece. This is disastrous! In terms of flexibility, the Herschel wedge wins. It just virtually turns any refractors into a solar scope! Well nothing to say & let the photos speak for them.

Equinox 120ED, TV 5X & Herschel Wedge

Equinox 120ED & Herschel Wedge

18-3-2010 Small Scope Big Prominence

2010-03-18T08:37:00.000-07:00

God bless! We have sunshine today and I have 2 free lessons at the right time. Sun light just shone on the corridor just outside the laboratory! I setup my LS35T quick and did observation. Gosh! I saw a very big prominence and it was the biggest prominence I have ever seen! May be I am too green in solar observation, but it is biggest prominence recently. See if I have to monitor it tomorrow.

LS35T, DMK41, Stack best 95% out of 150 frames

Goodbye my C5

2010-03-18T08:25:00.000-07:00

Last year I ordered a Meade 8 SCT and waited for long time. Meanwhile I bought a used C5 from a local astronomer. It is a very handy scope and I used to use it to do solar observations and perhaps some planetary observations. Finally I got my Meade 8 SCT. It seems that there is no much use of C5. I don’t want it to sit inside the store room. So I decided to let this classic C5 go! It was sold to an experienced stargazer in 3rd March 2010. This ended our 10 months relationship! So people asked me why I sell this classic C5. The reason is simple. I don’t keep any scope which is not used frequently. The other reason is that I can spare the money to buy other instruments. This photo is the goodbye kiss to my C5.

The Long Waited Sun

2010-03-10T05:59:00.001-08:00

It has been cloudy, rainy and humid for more than two months in Hong Kong. The winter was exceptionally bad this year. No stargazing and sungazing for more than two months since last Christmas Eve. Although it has been very busy today, I could not stop myself from the long waited sunshine today. I spent less than one lesson to shot the sun. Everything was in a rush!!!
LS35T, EQ3Pro, DMK41, Registax, PS, top 90% quality of 450 frames stacked

Small 60mm China made refractor and reflection

2010-02-13T08:04:00.001-08:00

I just finished the China made 60mm refractor (C60) testing, bulk order from a small China factory. As the absolute measurement is not possible, I compared it side by side with another 60mm Takahashi FS60C. The price difference is 9 times, one would expect there would be big difference. So this report roughly tells you what it means by big difference.
At a first glance, the finish of C60 is bad, however the design is good. It has an extension tube and the eyepiece holder is even equipped with compression ring! One just needs to screw the extension tube into the end of the focuser and it works for webcam.

The handcraft is by no mean good! So what about the optics? I used Nagler 2-4mm and 3-6mm zoom in both C60 and FS60C. The big problem of the C60 is that chromatic aberration in any magnification is pronounced, especially when viewing high contrast objects. In fact I tried to use Baader Planetarium 8-24mm zoom to test the low magnification performance of it, the problem persisted. Another bad design of the C60 is that the inner tube of the focuser is very long and the inner diameter is smaller than 60mm. I guess this makes the effective aperture of C60 smaller! Look at the attached photo. On the other hand, the chromatic aberration in FS60C is very small. One can detects it when the magnification is very high, say larger then 355/2.5=142X. Of course this is a rough figure. The result may vary from different viewing conditions. My subjective opinion about the maximum acceptable magnification of both scope are:
C60: 220/2=110X
FS60C: 355/3x2.5=296X
Beyond the above magnifications, the contrast would be too low.
I used to use 5-point scale to rank telescope. If I keep on use this scale, I must give the C60 negative score! However I found that I was spoiled by those ED/APOs! I have several refractors. Some are achromatic and some are EDs or so-called APOs. After I got the ED/APOs, all my achromatic refractors are sitting in the store room and gather no more photons. I do most of the visual observations and imaging with ED/APO refractors. I never seriously look back the achromatic refractors again. Until this test, my instant feeling was that I bought garbage! Then I dug out my Meade ETX70. Although the finish is good compared with C60, the chromatic aberration is very bad. I do remember I was once satisfied with these achromatic refractors. Now I say they are garbage! I was really spoiled by those ED/APOs! In most of the time when I do optical testing of those ED/APOs, I deliberately push the magnification to limit, point to bright and high contrast objects and do rigorous star tests etc. Radically fault picking the scopes. Sometimes the differences can be only be identified by experienced telescope users. In fact if one is not doing a side by side test, I doubt the results are reliable. I asked myself is it the way to promote astronomy. I can say virtually all the telescopes we used nowadays are much better than the one used by Galileo 400 years ago. His achievement in astronomy was tremendous! I reckon that always talk about prestigious telescopes may not be the way to promote astronomy because the price of those prestigious scopes are too high in some sense. We should introduce more good value scopes, for example Sky-watcher Mak 127, Celestron Nexstar 4SE or even binoculars, to the public. These good value scopes once lead me to the world of astronomy. Anyway, in terms of optics, test result is follow (10-point scale):
C60: 4 (Moderate blue and red aberration, but more contrast than ETX70)
Mead ETX70:5 (Severe violet aberration, but sharper than C60)
Takahashi FS60C: 8 (Sharp, high contrast, by all mean winner in this test)

FS60C Vs C60

Look! The large inner diameter of the focuser tube!

C60 Vs ETX70

Testing the limit of FS60C (355/3x2.5=296X)

31-1-2010 Solar Image

2010-01-31T08:06:00.001-08:00

Yesterday got a call from the dealer. He said that my LS35T problem is arisen from the objective, not the etalon. The objective got serious astigmatism. Gosh! When I hear this I was scared because my LS35T is a special edition and the objective was made by Carl Zeiss which means there would be no replacement! The current LS35T uses non-Carl Zeiss objective. I am lucky enough that the last LS35T, there are totally 4 Carl Zeiss editions in Asia, is not sold yet! I can have replacement right the way! Hooray! I will take it home this week and fully utilize it as my F.7 class will be finished.
After more than one month of bad weather. Today is a sunny day. I used the dealer’s courtesy LS35T to shot the sun. Although there is no sunspot, I got two big prominences! Since the diameter of the sun is about 110 times than that of the Earth, the biggest prominence is about 3 times the size of the Earth!

LS35T, DMK41, Porta, Registax 90% quality of 300 frames, PS CS4

LS35T Sent for Repair

2010-01-29T07:43:00.000-08:00

After watching the dealer’s Ha angular eclipse photos, I smell something fishy about my LS35T. I watched LS60T, LS70F and LS100T before in David’s solar party. As there were many big solar scopes, I didn’t draw much attention to the LS35T. After I bought my LS35T, I found the detail of the sun surface is not shown clearly. Originally I thought that was normal, LS35T cannot be compared with those big scopes. As u can see in my 1st Ha photo which was shoot by my LS35T. It seemed that it was abnormal. So I found David, who is an experience sun-gazer. He confirmed that my LS35T needed to be repaired. So I sent it back to the dealer for repair. The scope needed to be sent back to US. The dealer is so kind that he lent me his own LS35T. During the waiting, I can still do solar observations! Great! When I went to David, he let me tried his prestigious unobstructed LS70F and APM 80/480. Visually the surface detail shown was wow! The photo was taken by this setup. The photo was not particular good because of my bad skill!

16-1-2010, APM 80/480, LS70F Unobstructed Version, DMK 41

1st Solar Ha Image

2010-01-16T07:33:00.000-08:00

This is my 1st Solar Ha Image I took on 12th Jan 2010. This was certainly a bad image. Although it showed a sunspot, even a white light filter can do it. I have used several times my LS35T for visual observation. I knew it shows less detail compared with LS60T, LS75F or LS100T, but I didn’t know it is abnormal or not. Today I confirmed my LS75T is abnormal after I consulted my friend who is experienced in solar observation. Good grief! I need to send it back to the dealer. Hope to get it fixed quickly!

LS35T, HEQ5Pro, DMK41, Registax 5

High Resolution Lunar Mosaic

2009-12-26T10:27:00.000-08:00

I did a quick imaging work in Christmas Eve because I needed to rush home for dinner. The seeing was 5/10 and the transparency was 4/10. Originally I want to shoot both Jupiter and moon. However I didn’t make it for the Jupiter. I used the Equinox 120ED and the 5X Powermate for the Jupiter imaging. The effective focal length was 4500mm. It was just too difficult for me to get the image on the DBK21 CCD. I tried for an hour and finally I gave up and switched fast to the moon. It was a good exercise for me to shoot the moon in high magnification. I used the Equinox 120ED and 2.5X Powermate. The effective focal length was 2250mm. It was longer than the focal length of C8. In order to save my work, I intentionally used more margins. I don’t want to ruin the whole image by miss a small parts of the moon. The final mosaic is a composition of 22 photos. I found it was difficult to make the sharpness uniform in all 22 photos. The underlining key is the selection of alignment points, not the number of alignment points and the wavelet. After process the image for more than 15 hours, I gave up! This is the result.

Click here for full size images:

http://wphoto.myvnc.com/24-12-2009_original.jpg

http://wphoto.myvnc.com/24-12-2009_original_bg_rotate.jpg

Moon age 7.9, Equinox 120ED, EQ3Pro, DMK41, Registax 5, PS CS4

Filled background and rotation applied

My Dark Age

2009-12-19T07:10:00.000-08:00

Despite the recent cloudy weather in Hong Kong, the weather seems going to be good in the Christmas holiday. I wish clear skies are waiting for me! However, I was totally down today! I went to the Lion Rock Mountain today with the Hiking Club members. Apart from the foggy weather, it was cold and dry. It was good for hiking! However it was my fate too! When we walked for an hour, I needed to check the map to make sure that we were in the right trail. As I needed to find the map from my backpack, I asked one of my students to hold my camera for me. While I was reading the map, he suddenly dropped my camera! Good grief! My D80 and 18-200mm VR were gone! I guessed the D80 would be totally lost! I am not sure about the 18-200mm VR. It needs optical alignment for sure. Anyway, I need to bring them to Nikon and see if they can be recovered. They are now in Intensive Critical Unit, ICU! I told my student that this accident can be fixed by money. I will pay for my beloved camera and lens. But some accidents in physics lab would not be fixed by money, perhaps fatal or irreversible! One must be very careful in handling equipment. Anyway, this is not the end of the story. When we almost finished the hike, I wristed my two ankles 拗柴! It was the first time I hurt both ankles simultaneously! In fact I haven’t seen any people hurt their two angles at the same time! Poor me! I wish I can recover quickly. Otherwise it will ruin my Christmas holiday completely! No stargazing!!!

My two ankles were wristed!

My D80 was seriously damaged! See the gap between the lens and the body. This part is supposed to be very tough! But cracked now!!!

These are the bits and pieces from the inner part of D80 and battery compartment. In fact some parts are missing!

Reprocess the 28-11-2009 Lunar Mosaic

2009-11-30T01:54:00.000-08:00

The previous lunar mosaic was not very good. Some parts of the moon were blurred. A quick reprocess of one of the avi file tells me that the problem arises from post processing. The problem was mainly due to the poor selection of the alignment points. After some experiments, I found that the optimal number of alignment points is 4 to 5. The location of the alignment points is also important. I cannot generalize the general rules, but it seems that both high and low contrast locations are important. If you want to reveal the details of the low contrast location, one needs to pick an appropriate location for it. So don’t just focus on those high contrast locations.

Moon age 10.636, Equinox 120ED, EQ3Pro, DMK41, Registax 5, PS CS4

Lunar Mosaic

2009-11-28T00:22:00.000-08:00

Last night the sky condition was good. Both seeing and transparency were about 6/10. I went to the roof of my school and did observation and imaging. Since I needed to go to a wedding banquet, I did everything in a rush! I deliberately used the Equinox 120ED to make a high resolution lunar mosaic. The image was makeup of 4 images. This was the first time I made it! My next challenge is to use a 2.5X Powermate to make a lunar mosaic!

Moon age 10.636, Equinox 120ED, EQ3Pro, DMK41, Registax 5, PS CS4

The Lunar X

2009-11-25T02:55:00.001-08:00

Yesterday after school, I was fed up with my work and I missed two consecutive observation days already. I don’t want to end up with sorrow and I don’t want to waste the clear sky. So setup telescopes quick and enjoy!

This was the first time I seriously use the new eyepieces, Baader Planetarium 8-24mm zoom, Tele Vue Nagler 3-6mm zoom and Tele Vue 2-4mm zoom. However, the instrument is nothing more important than the observation. I started the observation at about 6:00pm. The moon & Jupiter were hanging in the sky. When I pointed the M8 ACF to the moon, I quickly recognized the Lunar X. This is the first time I saw it and I remember that it can be seen in certain moon phase. However, I must good home because my two little daughters were waiting for me. So I packed all the telescopes and went home. I thought I can take the Lunar X after dinner.

After the diner and father’s evening duties, I started to image the moon at about 10:00pm. Oh Gosh! The Lunar X was not as obvious as that at 6:00pm (Moon age 7.615). It was stand out at 6:00pm, but now it was pale. I did everything in rush. Finally I made it! After that I search the Lunar X information in the Internet. The Lunar X can only be seen in 4 hours just before the quarter!
http://www.astropix.com/HTML/SHOW_DIG/097.HTM
Lucky me! I made it! My next challenges are high resolution lunar mosaic and high power magnification lunar features.

Moon age 7.781, Equinox 80ED, DMK 41, Porta mount, 482 out of 500 frames stacked, Registax 5, PS CS4

Equinox 66 Vs Tak FS60C

2009-11-20T06:10:00.000-08:00

A long awaited comparison, Sky-watcher Equinox 66ED Vs Takahashi FS60C. I borrowed the Equinox 66ED from the dealer for sometimes and waited for my friend, David, for quite a long time. The sky was not cooperating. Our schedules were not matching. Finally I gave up the comparison through celestial objects, but terrestrial observation.

I went to David’s school at about 5:00pm yesterday. We setup all the scopes quickly. David’s students were good helpers and little judges. I guess they are trained to be experienced telescope users. The main disc was Equinox 66ED Vs Tak FS60C. However, there was another super star TMB 80/480. The main concern was the chromatic aberration. We selected some white light sources from distant buildings. In addition, we luckily found some really small bright spots which can be treated as point source. So we did “star test” as well. However, one should be reminded that these artificial objects were much brighter than Sirius and even Venus. Using these artificial sources was extremely harsh to telescopes.
At the first sign, both scopes are strongly built. I like both focusers, although Tak FS60C got no dual speed, it is firm and solid. While the Equinox’s dual speed focuser makes focusing easier. We used the Nagler 2-4mm zoom and Nagler 3-6mm zoom. Ordinary diagonals used were used. For comparison purpose we set the magnifications of Equinox and Tak to 400/3 = 133X and 360/3 = 120X respectively. Despite low contrast, both scopes didn’t breakdown even at 2mm eyepiece focal length. The trends of CA of both scopes were similar. There were some violet in front of the focus and some green behind the focus. However the degree of CA was different. The CA of Tak FS60C was very small. The CA of Equinox was small. Both scopes gave good “star test” results. All the diffraction rings were symmetrical. However the pattern in front of the focus and behind the focus in the case of Tak FS60C was a bit better. We repeated all the comparisons by swapping the Nagler 2-4mm zoom and Nagler 3-6mm zoom, the results were the same, which means the differences were not from the eyepieces, but the scopes. Anyway, the difference in CA was not big in fact. So what really make the difference in this comparison? Resolution!!! David and I found that the resolution tells the difference. Tak FS60C gave shaper images.
About the CA of Equinox 120ED, it was reported in Cloudy Nights that if one stops down an Equinox 120ED to 110mm, it was virtually color free. So I tested this idea in Equinox 66ED. Since I could not find a compass this morning, I used a cap to draw a circle. The diameter of the stopper was then 58.5mm. There was still CA exists and showed a bit improvement in violet. I couldn’t see improvement in green.
Well, the final verdict cannot be made. The reason is that in real sky observations, stars are much dimmer that artificial lights. The observed CA in very bright artificial lights may not be detectable by human eyes in the case of real stars, so further test is needed.

At the end we try those eyepieces on the legendary TMB 80/480 quickly. We selected a very bright source. No kidding! We were not able to find any CA!!! We were rushed by janitor. So we didn’t try deeply the Nalger zooms on the TMB 80/480. Wait for next chance!

DIY Bi-scope Platform

2009-11-10T23:27:00.000-08:00

Being inspired by the China made telescope mount, I designed my own DIY Bi-scope Platform. My dad is a mechanic and crafted this platform according to my design and specification. The parts included are: Aluminum plate, Vixen Porta mount, Vixen dovetail saddle, Sky-watcher dovetail. The Bi-scope can carry two telescopes and some accessories. The weight of the platform is 3.4 kg. In this trial, I mounted an M8 (5.6 kg) and an Equinox 120ED (6.8 kg) on to the Bi-scope platform (3.4). The whole setting was mounted on HEQ5Pro. No kidding! The total loading is 5.6 + 3.4 + 6.8 = 15.8 kg!!! I believe this reached or beyond the limit of HEQ5Pro. This combination of Porta and dovetail saddle allows the fine tuning of two scopes such that they can be pointed to the same direction. There are some holes drilled on the platform which allow the flexibility to mount a camera. Anyway, it is not likely to mount two big telescopes on HEQ5Pro in field. Perhaps one big and one small telescope would be manageable. You know I am not strongly build and my car is small. Anyway, I feel very happy with this Bi-scope Platform. Thanks Dad!

Parts: Aluminum plate, Vixen Porta mount, Vixen dovetail saddle, Sky-watcher dovetail

Bi-scope Platform

Weight of Bi-scope Platform

Weight of Equinox 120ED

Weight of Meade 8" ACF SCT

15.8 kg on Sky-watcher HEQ5Pro

Holes for camera

A Quick Observation

2009-11-10T07:27:00.000-08:00

This evening the sky was clear, there was no cloud at all. I quickly setup the M8 and EQ3Pro at the school roof. This was the second time I used the M8 and last time was in a rush too. The sky condition was the second best I encountered in the school. The seeing was about 6/10 to 7/10. The Polaris was easily seen this time. I spotted about 10 stars in the sky. I spent about an hour on observing the Jupiter. It was not a serious comparison the M8 and Equinox 120ED. Although the M8’s image is brighter than that of 120ED, the color of M8 is pale compared with Equinox 120ED. I used the Sky-watcher 8-24mm zoom eyepiece. All the images were sharp with some deterioration towards the 24mm limit. I boosted the magnification to 2000/5 = 400X. Obviously the image was okay. Some color fringes could be seen however the contrast was bad. Once I boosted the Equinox 120ED to 800/15X5 = 450. Although not much detail could be seen, the contrast was bad. This means M8 and Equinox 120ED got similar resolution, but Equinox got better color and contrast. This conclusion might not be accurate. A side by side comparison would be more reliable. I will do it shortly.

Lunar Image Taken with Equinox 66ED

2009-10-27T08:39:00.000-07:00

Home observation again! Apart from the clouds running around, the seeing tonight was quite good. This lunar photo was taken by a small refractor Equinox 66ED and DMK41. Without much stacking skill, the result is follow:

Equinox 66ED, DMK41, best 442 frames stacked

Equinox 66ED, DMK41, 500 frames stacked

Equipment Testing: Equinox 66ED

2009-10-26T09:49:00.000-07:00

Following the testing of Equinox 66ED for terrestrial observation a few days ago, last night I carried out another testing for observing the moon and Jupiter. Here is my scoring scale:

6. Excellent

5. Very Good

4. Good

3. Average

2. Bad

1. Rubbish

This is just an impression marking and subject to be changed according to my experience in astronomy. Let me make it clear. I’ve seen the APM APOs. Those are prestigious refractors. The images are razor sharp and ultrahigh contrast. I rank it 6, excellent. This means for similar image quality, I will rank it 6. This scale will be changed if I find something better than APM APOs. This is a casual visual test. Ordinary diagonal and Sky-watcher eyepieces and Tele Vue Powermates were used. The observation site was my home. As this is a small telescope, it is no point to use it for deep sky objects visually. Use it for bright celestial objects are more sensible, say moon and planets, right? That’s why I tested it at home. Both seeing and transparency were modest. As mentioned in my previous test that for terrestrial observation, the image quality was very good if the magnification is below 80X. Once it goes beyond 80X, the contrast and brightness becomes very low and the color tone is bad. So it wouldn’t be promising to use this small refractor for terrestrial observation or birding for over 80X. Otherwise it is a small, but powerful weapon. The story is different for planetary observations. This is what I guessed in my previous test:

http://willisao.blogspot.com/2009/10/equipment-testing.html

“However, if it is used for stargazing, the magnification can be boosted further since the background is much darker. It all depends on what celestial objects you are going to watch.”

I found that for both lunar and Jupiter observation, the magnification can be boosted up to 200X, perhaps 220X! At such magnifications, the images still not breakdown and one can still see some details. Here were the results:

Lunar Observation:

Below 133X, all the images were very good. The chromatic aberration was extremely small.

400/15x5 = 133X (Good)

400/5x2.5=200X (Average)

400/2 = 200X (Average, this setting is a little bit better than that of 400/5x2.5 = 200X in terms of details and contrast)

400/9x5 = 220X (Average)

400/8x5 = 250X (Bad, the contrast is too low and not much detail can be seen)

400/5x5 = 400X (Rubbish, completely breakdown)

Jupiter Observation:

400/8 = 50X (Excellent, high contrast image can be seen, the color fringes of Jupiter were clear, 4 pin sharp Galileo satellites can be seen)

400/6 = 67X (Very good)

400/15x2.5 = 67X (Very good)

400/5 = 80X (Very good)

400/15x5 = 133X (Average)

400/2 = 200X (between average and bad, the Jupiter’s fringes still here, this setting is a little bit better than that of 400/5x2.5 = 200X in terms of details and contrast)

400/5x2.5 = 200X (between average and bad, the Jupiter’s fringes still here)

400/9x5 = 222X (Bad)

As an epilogue, I didn’t expect something good can be seen for a China made small 66mm refractor for 133 X or beyond. Now I was amazingly seen the moon’s craters and Jupiter’s fringes at 200X with this small China refractor. I was satisfied. So! What next? I really want to compare Equinox with Takahashi FS60C and Tele Vue TV60. Everyone says Takahashi is excellent, Tele Vue is fabulous! Later I will compare the Equinox 60ED and Takahashi FS60C, as I got a friend who owned an FS60C. But no luck for TV60! TV60 was claimed by Tele Vue and echoed by owners that it can be boosted up to 180X. This puzzled me now! What it means by 180X? Is there any contrast, color or sharpness deterioration? If the answer is no, the TV 60 can certainly go beyond 200X with some tolerance. This means TV 60 can go beyond 83X per inch. I cannot answer this… Anyway, wait for the battle between FS60C and Equinox 66ED.

Home Stargazing!

Sky-Watcher Equinox 66ED

Goodbye Orion Meteoroid Shower

2009-10-26T06:43:00.001-07:00

Last Friday, 23/10/2009, I went to PTC and see if I could catch the last chance to see the Orion Meteoroid Shower. The peak was in 21/10/2009, but the sky was not cooperating until last Friday! When I arrived at PTC, there was only one stargazer around. Finally I saw two shooting stars and my wife saw one only! How lucky! Anyway, the seeing was ok. I enjoyed the sky for 2 hours. My wife and I saw the Orion nebula, M42. Anyway, good luck for the coming Leo meteoroid shower.

In Search of Good Observation Sites

2009-10-26T06:25:00.000-07:00

The light pollution in Hong Kong is terrible. A good observation site is hard to find. The location should be as dark as possible, private car can be easily accessed, convenient to set telescopes next to the car, covered by mobile phone network, safe etc. The well known observation site is Pak Tam Chung’s coach park. It is reasonably dark and convenient. However, the light from the nearby public toilet is very annoying. In addition, it is also a rendezvous of midnight motor cyclists. Shui Hau & East Dam are very dark, but they too remote. From time to time, I look around when I am driving in order to find new observation sites. Recently I spotted a new site which is close to PTC, 烈士紀念碑, in Sai Kung. See the attached maps. The field of view is wider than PTC. There are two minor light pollution sources. Light pollution from southeast, Sai Kung, and from AMS Canoe Centre, northeast. The big plus of this site is that the field of view is much better than PTC. In addition, there is a nearby toilet, BBQ stoves and tables.

Equipment Testing: Meade 8 ACF, APM/TMB 80/600 & Equinox 66ED

2009-10-19T07:55:00.000-07:00

The past few days were in real rush! Setting S4, S5 and S7 Physics test papers were exhausting. I don’t know what was going on. Everything seemed came out at once. So many things tempted me to go away from my school duties! The sky condition seemed fairly good, replacing equipment, chance of getting new telescope, chance of trying different telescopes, chance of getting a used top class telescope etc. Finally I squeezed some time for hobby!
The long waited Meade 8” SCT AFC was finally settled! The order has been delayed for many times and I’ve disappointingly waited for half years. Finally I got an offer from a local stargazer who bought this telescope in a special offer given by the local dealer half years ago. The reason that he sold this M8 was that he got another extremely cheap LX200 offer. The M8 ACF he sold to me was very new. It has been used in field, Pak Tam Chung, for once only. I was lucky enough to get it because another stargazer told me about this and I responded fast enough to it, or the chance would go! It is very hard to get a used M8 ACF in Hong Kong. Although he sold me at the same price he paid half years ago, it was still a good price and it healed my pain at once! Last night, the sky condition was so so. The transparency was ok, but the seeing was bad. With clouds running around, I could hardly catch a few moments to look at Jupiter. Nothing could be concluded, but the M8 worked. The maximum magnification I tried was 2000/9 = 222X.
Another encounter was the trial of the APM/TMB 80/600 APO. I went to the Sky-watcher dealer and replaced the long tripod with a short tripod for the EQ3Pro. Sky-watcher is certainly a homely-made like manufacturer. Their product specifications change from time to time and even their dealer doesn’t know it! Their product specifications can be modified according to requests! This is odd, but flexible right! I am an efficient guy. I know the dealer got a used APM/TBM 80/600. It would be nice if I can have a look at it before it was sold to somebody else. I deliberately arranged the tripod replacement and the glance of the APM/TBM APO in one go. Ha Ha! In fact the main course was the APO… Well, it was daytime, I did the terrestrial observations only. The first eyepiece I tried on the APM/TMB 80/600 was 25mm Aspheric Orthoscopic. When you look through the eyepiece, the feeling was WOW! The image was so sharp and the contrast was so high. The image was sharp to the edge of the field. This telescope was the best I’ve ever seen for terrestrial observation! I cannot imagine what will happen if I use the APM/TBM 203 to do terrestrial observations! The color tone was warm. The Aspheric Orthoscopic gave good eye relief and the field was reasonably wide. The viewing was so pleasing and comfortable. When I put the 16mm TBM Super Monocentric, which is supposed to be a top planetary eyepiece, the off-axis image was a bit blur. However, the image around the principal axis was extremely sharp and of very high contrast. The color of the Mono was not as warm as Orthoscopic. I didn’t have the chance to compare these two eyepieces on viewing stars side by side that day. I couldn’t comment which one was better for stargazing. It would be nice to do it later. Finally I tried the 13mm Ethos. There is no need to mention about its field of view. The viewing was very comfortable. The image was sharp and the contrast was high. I couldn’t tell the difference in sharpness between Aspheric Orthoscopic and Ethos. Both are very good eyepieces, which need longer observation and being tested to differentiate. Again I was in a rush to go! So try again next time.
I borrowed the Equinox 66ED from the dealer for a short period of time. I tried it in daytime recently. A first look at this little scope, it inherited the beauty build of Equinox series. I have tried Equinox 80ED and 120ED, now the 66ED. The only Equinox I didn’t try is the 100ED. Well, the optic of this scope was good. I used Skywatcher eyepieces and Tele Vue 2.5X and 5X Powermates in the entire testing. For daytime terrestrial observation, if the magnification was below or equal to 400/5 = 80, the color, sharpness and contrast are very good. It doesn’t mean it will breakdown when the magnification goes beyond 80, but will not be too promising to use it for birding or other terrestrial observations as the contrast and the brightness are low. I tried to boost the magnification to 400/8*2.5 = 125X and 400/15*5 = 133X respectively. I was able to see the price tag of a fruit store. I guess the characters’ size was about 5cm and the store was about 1.5km apart. A quick estimated resolution to achieve such an observation is 5X10^-2/1.5X10^3 = 3.3X10^-5. The Rayleigh resolution, theoretical maximum, is 1.2X550X10^-9/66X10^-3 = 1.0X10^-5. It is not bad right! However, if it is used for stargazing, the magnification can be boosted further since the background is much darker. It all depends on what celestial objects you are going to watch. For the 200X, I tried in different settings, 400/2 = 200X and 400/5X2.5 = 200X. The 400/2 = 200X gave a slightly better performance in terms of sharpness and contrast. At such magnification, the contrast was very low. However, the image didn’t breakdown completely. One could still see some details. The corresponding magnification per inch is above 70X. It is a good figure already. I owned a small achromatic refractor, Meade ETX 80. Its optical performance cannot be compared with Equinox 66ED in terms of chromatic aberration and resolution. To be fair, the price of ETX70 was just a few hundred. Although optically it is a loser, it is a best buy.

Top equipment, but hazy sky!

2009-09-26T20:35:00.001-07:00

Last night I was in Tai Po. The main task was APO testing. The dealer imported a few APM/TMB APOs. It was a rare chance that one could have a side by side comparison of 100mm/F800mm, 130mm/F1200mm and 203mm/F1420mm APOs. The 203mm/F1420mm was owned by the dealer. The other two APOs were goods. However, it was ruined by the bad sky condition! The sky was very hazy. The seeing was very bad. The moon was covered by a yellowish Arabian mask. It would be nice if you are not stargazer. When I back home, I browsed around the Internet. It seemed that all local observation sites, like Pak Tam Chung, were disappointing. I got ready the equipment in my boot in the afternoon. It would be meaningful to know how good those APM APOs compared with Equinox. Finally I decided not to setup my equipment and just tried those APOs.
At a first glance, the tube material was robust lightweight polymer. Both 100mm/F800mm and 130mm/F1200mm can be mounted on EQ3Pro. I forgot to carry both APOs and got a feeling of how heavy they were, but they should not belong to heavy class. Everything was strongly and nicely built. The base and the bracket of the finder scope were quite unique. I would not say it is stylish, but the design concept was neither Japanese nor Chinese, but German. The Feather Touch focuser was solid. Well back to the main dish, optical performance. Both APOs delivered high contrast images. I tried another 12” Newtonian last night. The Newtonian deliver brighter images, but it contrast was far below than that of APOs at similar magnifications. We boosted the magnifications to 288X and ~500X for 100mm/F800mm and 130mm/F1200mm respectively. These mean we pushed the limit to 72X/inch (288X) and 96X/inch (500X) respectively. The 100mm/F800mm was able to handle 72X/inch. Although the Jupiter image was breakdown under 96X/inch for the 130mm/F1200mm, one could still see some color fringes of Jupiter. That was not a flat images disc of Jupiter.
Last night there were two points I especially want to mention, the chromatic aberration and the resolution of the surfaces the Jupiter’s satellites. When I used the APOs to observe the Jupiter, the north pole of the Jupiter was a bit bluish. The dealer said it was due to atmospheric chromatic aberration, not the chromatic aberration of the APO. Here comes the question! Is the dealer telling the truth? To me, this is a physics question. If the optics got no or low astigmatism, the chromatic aberration should be cylindrical symmetric. There should be false color around the star, not just appearance in certain direction. My conclusion is that the bluish color at the north pole of Jupiter was caused by atmospheric aberration. One can do some experiments to verify this. Use the same telescope to observe the same object and see if the position of the aberration changes with time. About the resolution of the surface of the Jupiter’s satellites, moon surface, we saw all four satellites, IO, Europa, Callisto and Ganymede. The dealer and I were not sure about the moon surfaces were revealed or they were just Airy discs. As the magnitude of those satellites were small, probably larger than 5. When I observed the satellites by the 100mm/F800mm APO, it seemed that I saw the 1st order diffraction ring, but I was not sure. But it was possible that it was Airy disc. When we used the 130mm/F1200mm APO, the image of the satellite improved a bit. The hazy sky kept on discourages us whole night. It seemed that the 130mm/F1200mm APO gave a more solid image. However, it was illusion or fact. We need to wait for the sky. But it is highly possible that these two APOs will be delivered to new owners. So what can I do! Ha! Ha! Use theory to justify it! As these two APOs were claimed to be diffraction limited, we can do some calculations and see if it is possible to see the moon surface.
The visual angles in arc second of the satellites are:
IO 1.2”
Europa 1”
Callisto 1.6”
Ganymede 1.7”
By using the Rayleigh Criteria, we can calculate the theoretical limit of the resolution of the telescope.
R = 1.2 L/D where R is the resolution, L is the wavelength and D is the diameter.
The resolution calculated is in radian, we can convert it back to degree easily. In order to get a feeling of how good is the optics, I assume the average wavelength of visible light to be 550nm. After some simple calculations, for diffraction limited optics, the resolution of different diameter in arc second is given below:
100mm 1.36”
130mm 1.05”
203mm 0.67”
It means that 100mm APO is not able to resolve the Jupiter’s moon surface. The image was just an Airy disc. The 130mm APO can barely resolve the Jupiter’s moon surface. The 203mm APO can resolve Jupiter’s moon surface. This is a simple discussion, meaning that if the optics is diffraction limited, it is possible to resolve it. On the other hands, the practical optic is not possible to go beyond the theoretical limit.

APM 100mm/F800mm

APM 130mm/F1200mm

Newtonian 305mm/F8.5

Equinox 120ED and DBK21

2009-09-23T22:48:00.000-07:00

Last Friday,18th September 2009, I got a chance to use the Equinox 120ED and Imaging Source DBK21 and DMK41 in the field. The sky condition was exceptionally good. I went to Pak Tam Chung at about 10:00pm after monitoring my daughter’s homework. Since I got lot of outstanding tasks, time was limited for me. I planned to image the Jupiter and one to two deep sky objects, but I end up with the Jupiter only. The main reason was that I was inexperience in handling the Imaging Source camera. I’ve learnt the basic of how to image Jupiter from David, but lack practice. This was the first time I use the DBK to image Jupiter. I knew some crucial parameter in imaging the Jupiter. However mirror setting could ruin the photo! It takes time to learn and art cannot be rushed!

When I arrived PTC, I started the setting at once. I was kind of slow and inexperience in setting up the equipments. Since this telescope was a rare species in PTC, It attracted some stargazers. Finally when the setting was done, we viewed Jupiter. Everyone was amazed by the 120ED. Mirror God used his, prestigious telescope tester, Takahashi 3.6mm eyepiece, to test the Equinox 120ED. Here was his exact wording:

"Hmm... 幾好幾好！真係唔錯！雖然唔係一級的鏡，只是色差差少少！好少！只係輸比Astrophysics少少！想不到兩枚玉都有咁好performance！"

This was not the end of the story. When I finished the setup of DBK 21, the movie shocked everyone. It was because I was green in setting the DBK, everyone knew it when they saw my clumsy acts, but the movie was quite sharp already before stacking. It was good because the seeing & transparency were good. These unleashed the power of Equinox' optics and the power of DBK's electronics. My comment is that Equinox 120ED delivers high contrast, high color saturation and high resolution images in its own class. The color was a bit warm and yellowish in viewing Jupiter. The price is good. No complain for such performance price ratio, $13800 for a 120ED! If one wants to take serious photos, a Feather Touch focuser is needed, perhaps a high quality reducer. I am still very busy on school’s work and no time to learn how to stack the photos. The photo below is just a default click-click-click output of Registax 5.0. I will process it seriously later.

Jupiter, Equinox 120ED, TV 5X, DBK 21

The Delighting Jupiter and Moon 賞心「月木」

2009-09-05T08:40:00.000-07:00

Starting from mid August, I was busy preparing the commencement of the academic year. Although I had a few stargazing activities, I didn’t have time to record what I have done. I did visual observation for the Jupiter opposition. I tried my friend’s Obsession 18” UC. I placed the telescope order for my school etc. I was lucky enough to have the full support from my principal that I can buy enough equipment to start astronomy in school. We bought a Sky-Watcher Equinox 120mm ED Refractor, a Sky-Watcher Dobsonian 12” Collapsible, Sky-Watcher EQ3Pro equatorial mount, Binoculars, The Imaging Source DBK 21 and DMK 41 etc. All the equipment enables me to start stargazing activities, promoting science education and enriching the NSS Physics teaching in Astronomy and Space Science.

Last night was the first stargazing activity this academic year. I made an elegant Chinese name for this activity, 賞心「月木」Delighting Jupiter and Moon. I used the Stellarium to find out the appropriate time to hold this activity. It was because my school was surrounded by a public housing estate and a hill. The field of view from the school roof is very narrow. Without careful planning, the observation would definitely be doomed! Originally I planned during the observation time, the Jupiter and the moon would appear between the gap of two buildings, finally I changed the observation site from the school’s roof to a nearby roundabout. I guessed students would be happier with an unobstructed view.

After a short introduction about the Jupiter and the Moon, we went to a nearby roundabout. The transportation was easy as we had about 20 students. However, the setting was quite exhausting! The temperature was high and I needed to setup three telescopes. Finally I gave up and ended up with two refractors. You know I need to control and discipline about 20 students in the street and at the same time I needed to setup the equipment, it was really something! A few of my students were good. They asked if they could help. But I did not have enough time to train them about the setting. I dare not to let them do it! I don’t want to risk the expensive equipment. Well! I will train them afterward. Anyway, I finished the setting in wet! When I finished setting up the first telescope, Equinox 80ED, everyone was amazed by the Moon. This was the first time they saw maria and craters. The second wave came after the setting up of second refractor. The target was Jupiter. Everyone was shocked by the Jupiter and its 4 moons, Io, Europe, Ganymede and Callisto! This was the first time in their life that they had such a close contact with Jupiter! I was the prime master of climax! I deliberately increased the magnifications gradually. Every time when I boosted up the magnification, changed to a shorter focal length eyepiece, everyone was so amazed and excited! The only defect of the activity was that students needed to wait for a long time! The queue was quite long! When it was about 9:30pm, a few students reported me that there were a few drops of rain! I was scared and packed all the telescopes at once. When we backed school, there was no rain at all! What a false alarm! Some students were not very happy because they didn’t have a chance to look at the Jupiter! I promised them to organize anther activity shortly and they will have the first priority to join!

After dismissing the students, I stated in the school and did some more observations with another Physics teacher in the school. We used the Sky-Watcher 12” Dobsonian and Equinox 120ED. Due to the light pollution, we only observed the Moon and Jupiter. Both seeing and transparency were modest. The magnification was about 200-300X. We were not able to explore the limit of these two telescopes. However, the primarily visual ability was good. A further test is needed.

Laser Hazard

2009-08-15T07:18:00.001-07:00

As a physics teacher, I clearly understand the potential danger in using laser. The power of ordinary laser pointers is large enough to hurt eyes in a few seconds if direct laser beam is shone on the eyes. The damage is Irreversible! The green laser pointers used in stargazing are much more powerful than that of ordinary laser pointers. Usually the power of a green laser is larger than 10mW. The power of ordinary laser pointer is usually less than 1mW. One can imagine what will happen if green laser beam is directly shone on eyes! Even the scattered light may hurt your eyes. It is a good practice to turn on the green laser at a level higher than the eye level. In addition, I am used to standing behind the one who are using the laser. Last night I encountered a very dangerous situation. As usual I stand behind the one who are using the green laser. He was shining the laser beam to the eyepiece and the laser beam came out from the objective. Ah.. This was a new method to test the direction of the telescope. While I was watching at the back of him, the scatter laser beam shone on my eyes! Gosh! Since the field was very dark. I went to the toilet and see if any problem with my eyes! God bless! Yeah! There was no blind spot visually! I guess most eyepiece cases are black in color. This lowered the intensity of the scattered laser beam. If not, the result would be disastrous! Well! After this bad experience, I have concluded the followings precautions:
1. Make sure no people in the direction of fire.
2. Shorten the fire time when you fire the laser.
3. Don’t wear shiny watches or decorations on your hands when you operate lasers.
4. Don’t look at the area around the laser pointer, even it is not directed at you.
5. Stand sideway to the one who is operating the laser.

Equipment Review

2009-08-15T06:00:00.000-07:00

Back to spring of this year, I started my interest in astronomy. I bought my very first binoculars from Grand Eye, read books and surfed the Internet. Astronomy has become my hobby. I don’t know how long I will stay with this hobby. Apart from my major, physics, in the past I got several hobbies, computer, music, philosophy, Chinese literature, English literature, aquarium, psychology etc. Once I get into the hobby, I will push myself to learn it. My character is that I will get myself to a certain level in a specific field. Now astronomy is my craze! After a while, perhaps several years, I will stop. However, I will pick up again after leaving it for some time. Different books can be found in my bookshelf. I bought several telescopes in the past few months, 10x50 binoculars, 10x42 binoculars, unbranded 5” refractor, NexStar 4SE, Equinox 80ED, C5, LS35THaDx. The NexStar 4SE OTA was sold because of the perchance of C5. I think C5 is the upper limit of a grab-and-go scope for me. Now the C5 become my most favorable scope because of the delayed arrival of Meade 8” ACF SCT. My recent interest is planetary imaging. Without a long focal length telescope, I cannot go too far. In term of optics, I like Equinox 80ED. It is high contrast, good color tone and good resolution. The dead knot of 80ED is that, its focal length is too short for planetary imaging. However, I am sure that it will become my favorable weapon in deep sky imaging. It takes time for me to be ready for deep sky objects which involve in skills and equipment. We have fewer numbers of solar planets than the number of deep sky objects. Deep sky objects are gorgeous, huge, mysterious and unreachable! After waiting for more than a week, finally a ridge of high pressure started to form. The sky condition last night was fair, but just could not wait for any longer. I went back after a wedding banquet! When I arrived at PTC, it was 11:30pm already. Due to limited time, I tried the newly bought Tele Vue 5X Powermate and did a visual test. I told Bingsze to bring his Meade 5X TeleXtender so that we can do a fair test on both barlows (Powermate is in fact exactly a bawlow optically). The local dealer of Meade did this test before, but it is not convincing. The test result and photos posted by him were unexpected. From his photos, Meade beat Tele Vue! As Tele Vue is the icon of top quality in the field, people suspected the result.

http://www.grandeye.com.hk/barlow_comparison.htm

However, there is no follow-up from different parties. My curiosity drove me to find out the answer. I did a preliminary visual test last night. The telescope used was an unbranded 110ED and the eyepiece was Sky-Watcher 5mm eyepiece. The target object was Jupiter. There were totally 4 stargazers involved in the test including myself. In terms of visual observation, we cannot reach the same conclusion. One of a well known stargazer, Mirror God, said that the two 5X barlows were very close. However Meade 5X TeleXtender got a bit more chromatic aberration. He added that it would be better to use Newtonian to perform the test, as it is chromatic aberration free. In terms of cost performance ratio, Meade wins. Bingsze said the performances were very close and Tele Vue got a bit better in chromatic abberation. Lewis said both barlows got very similar in revealing details, but Meade got a bit better chromatic aberration. My conclusion is that the performances were very close visually. Powermate reveals a bit more details and the contrast is a bit higher. Since the performances of the two barlows are very close, we need to perform another photographic test next time. However, we all think that as the differences were hard to tell and we did not come to the same conclusion. The Meade 5X TeleXtender should be the best buy because it just costs about 60% of Tele Vue 5X Powermate. However this test was not comprehensive. It is desirable to use a Newtonian to perform the visual and photographic test.

Tele Vue 2.5X and 5X Powermates

Last night I also tested the unbranded 127mm refractor which I bought from Boss Kwan. It has been sitting in the store room for a few months. Every time I got a chance to go stargazing, I used to test the more expensive equipments I owned. They are Equinox 80ED, C5 and NextSTar 4 SE. It is a prejudice! I found that this unbranded 5” refractor was good in the sense that the resolution is reasonably high and the image was bright. The weak point was obviously the chromatic aberration. The chromatic aberration of this 5” refractor is considerably better than my other achromatic refractor, ETX 70. Purple edge was shown when it was focused before the focus. Green edge was shown when it was focused beyond the focus. When it was in focus, there were a bit greenish edges. The view of Jupiter was bright, sharp and showed good details. After viewing this unbranded 5” refractor, I must say it is my excellent choice! It is simply unbeatable! No complaint for just $1680!

Unbranded 127mm F750m Refractor

Sidewalk Astronomy and Telescopes Watching

2009-08-02T08:24:00.000-07:00

Last night neither transparency nor seeing was good. However, it was a year of International Astronomy’s monthly activity, sidewalk astronomy. The activity was held in Tin Shui Wai, which is far away from Tseung Kwan O. I was happy to join the activity because my wife decided to go with me. When we arrived virtually all the telescopes were pointing to the moon. This was the brightest object that could amaze the general public. The most interesting thing for me to join this activity was I can have a chance to try different telescopes. The biggest telescopes are always eye-catching, the TMB 8” APO and the Takahashi M-250. Just an impression, the TMB 8” APO gives better contrast. I couldn’t tell the different between sharpness because they were using different eyepieces and the magnifications were different. Anyway the Ethos eyepiece was impressive in terms of view angle. I just wonder my eye’s view of view is too small compared with Ethos FOV! It just gave you a feeling of cruising around the moon. One cannot describe the FOV of an airplane’s window! Well all these, 8” APO, 10” Takahashi and Ethos, are expensive. I deliberately look at some down to earth telescopes. Believe it or not, Sky-Watcher 5” Maksutov-Cassegrain was really good. The image of the moon was crispy and the contrast was high. I remembered once there was a used one in the forum a few months ago. The owner asked for $1700 if I remembered correctly. Hmm…. I missed a chance.

TMB 8" APO

Takahashi M-250

After I walked around for a while in Tin Shui Wai, I decided to go to have my own star gazing. I rang my friend Lewis and our destination was Lung Ha Wan. We arrived at Lung Ha Wan at about 10:30pm. But the favorable location was occupied by some midnight divers! Gee! We wanted to try a new location, but it was just being occupied by others! Anyway, Lewis and I looked around and see if it was a good location for star gazing. But sky was very hazy and we could only see the Vega, the Jupiter and the moon. As there were no favorable car parks, we decided to go to good old Pak Tam Chung.
When we arrived Pak Tam Chung, there were no star gazers! I was fooled by those posts in the forum. Maybe everyone went to Tin Shui Wai. Well! We two lonely twins stated to setup our scopes and practice. The sky condition became very bad. When we arrived we could see the blurred moon, the fading Vega, the dim Polaris and Perhaps the bright Jupiter. I tried to setup the HEQ5Pro as quickly as possible. At the point I wanted to do the polar alignment, the Polaris was gone! So I used the compass to solve it. Unexpectedly the alignment done was quite good. The tracking of Jupiter was good. We shot the Jupiter with different imaging device, D90, 450D, SPC900NC and LPI. Both D90 and 450D have life-view which was very useful in focusing. But all the photos taken by D90 were unsatisfactory! We don’t know clearly why D90 failed. Maybe it was because of the flip mirror of D90 in the life-view mode flips before the release of the shutter, while 450D not. The small vibrations of flipping the mirror caused the burred images. As a Nikon user, I need to figure it out! This needs another investigation. My second task was to align the NexStar 4SE mount. It just couldn’t track the sun probably during the recent solar eclipse. I believe that ex-owner didn’t get it alignment in 2-star alignment or 3-star alignment once. According to the manual, one needs to get NexStar alignment once with at least 2-star alignment once before it works properly. However the noxious clouds covered the sky. You know! Finally I gave up and went to have dessert in Sai Kung. Today I tried to process my photos. I still don’t know how to use Registax. The photos shown were just click-click-click product.

Jupiter: C5, TV 2.5X, ISO 1600, 1/25, 450D

Jupiter: C5, TV 2.5X, ISO 1600, 1/25, D90

Jupiter: C5, SPC900NC, 1200 frames, Registax

Jupiter: C5, TV 2.5X, SPC900NC, 1200 frames, Registax

Solar Eclipse Photos Processing

2009-07-23T07:52:00.000-07:00

After taking a rest and having summer class, I can process the solar eclipse photos took yesterday. I want to make something special rather than post a lot of photos in my blog. Finally I made two photos. One is a close-up and the other one is a wide-angle. I used the photos taken by using C5, Thousand Oaks type 2+ filter, D90 and HEQ5Pro, to make the solar eclipse close-up photo. I used the photos taken by using 18-200mm VR, Baader solar film and D80, to make the solar eclipse wide-angle photo. I like the orange image produced by the Thousand Oaks type 2+ filter. It gives me a moody and warm feeling. On the other hand, the Baader solar film gives white images. It gives me cool and harsh feeling. Anyway, from the photos, one can see that some photos are interfered by clouds. The bloody clouds ruined the last few minutes of the eclipse! Life is like this! Never mind! Just enjoy the process and happily wait for the next solar eclipse.

I like this one the best. Sometimes clouds decorate the eclipse!

When I process the photos, I find I can do it better next time. First of all, I used the programmable shutter to shoot the photos. However, the time interval was two minutes and one minute when the eclipse was close to maximum. This strategy was not so flexible when I process the photos. At the end of the day, one needs to select constant time interval photos in order to give a dynamic feel of the eclipse. As you don’t want the photos to overlap each others, so the desired time interval would be three to four minutes. However if you do this, the noxious clouds or other unexpected event happened, say an airplane fly by, you are forced to miss one slap-shot! So if you set the time interval to one minute, then you can have better options to select from. In addition, if you have a chance to observe the total eclipse, it is better to use the full power of your camera. The corona is easily missing!

22-07-2009 HK Partial Eclipse

2009-07-22T08:10:00.000-07:00

Today is a long waited solar eclipse. It is a long day for me. Handling several telescopes and photographic equipments made me busy perhaps very excited! Luckily I got some closed-up, wide angle and some movies. However, the webcam didn’t work well and finally ruined the H-alpha photos. The auto focus of the DV didn’t work properly, so eclipse movie gone! What are left are some photos. Shortly after the eclipse activity, I got several appointments to go. I don’t have time to process the photos today. Here are some pre-release.

I was busy setting telescopes and photographic equipments

C5, Thousands Oaks 2+, HEQ5Pro, Prime Focus, D90, ISO 1600, 1/250s (8:16am)

C5, Thousands Oaks 2+, HEQ5Pro, Prime Focus, D90, ISO 1600, 1/250s (8:32am)

C5, Thousands Oaks 2+, HEQ5Pro, Prime Focus, D90, ISO 1600, 1/250s (9:04am)

C5, Thousands Oaks 2+, HEQ5Pro, Prime Focus, D90, ISO 1600, 1/250s (HKT 9:23am)

C5, Thousands Oaks 2+, HEQ5Pro, Prime Focus, D90, ISO 800, 1/125s (HKT 9:39am)

C5, Thousands Oaks 2+, HEQ5Pro, Prime Focus, D90, ISO 800, 1/250s (HKT 10:13am)

C5, Thousands Oaks 2+, HEQ5Pro, Prime Focus, D90, ISO 800, 1/125s (HKT 10:31am)

By the way, I didn’t catch the last 15 minute of the eclipse because of the bloody clouds! Good grief!

Finalizing the Preparation for the Partial Eclipse in HK

2009-07-21T04:18:00.000-07:00

It is a pity to miss the longest total eclipse over the past 500 years! However it is not responsible to leave my family. My little baby, daughter and wife need me. Anyway, if I leave HK and go to China, I am not able to use lot of equipments to record the whole process. I spent about one week to plan this activity. I used the Baader solar film to tailor made some filters for telescopes, binoculars, camera and DV etc. Here is my equipment list:
C5 + Thousands Oaks Type 2+ + HEQ5Pro + D90 (Close-up solar photography)
Lunt LS35THaDx + NexStar 4SE mount + ToUcam SPC900NC (H-alpha photography)
D80 + Lenses + Baader film (Wide field photography)
JVC MC500 + Baader film (Video recording)
Equinox 80ED + + Baader film + Porta (Visual observation)
10x42 Binoculars + Baader film (Visual observation)
Eclipse Shades (Visual observation)

This is a challenge for me to handle them all. I am not familiar with star alignment, especially in daytime. I tried once the NexStar 4SE mount once in daytime, but the tracking of the sun was modest. This was probably due to my green experience. The worst case is that I don’t have any daytime star alignment with the HEQ5Pro. Wish me all the best tomorrow. Unlike the deep sky objects, the poor tracking of the sun will not affect the photos a lot. If the tracking is good, I can free myself to enjoy visual observation. About the H-alpha observation, I think most stargazers, perhaps sungazers, will not use H-alpha scopes to do eclipse observations. This time I just do it for fun and see what will happen. Since the stock LS35T focuser cannot get the ToUcam in focus, I need to wait for the customized adaptor. The adaptor was arrived two days ago. I don’t have enough time to familiarize the combination of LS35T and ToUcam. Wish me good luck! Go to sleep and go to Clear Water Bay early tomorrow morning! Cheers!

PTC’s Starry Night: Equipment Testing

2009-07-18T08:40:00.001-07:00

Yesterday was the day before the Typhoon. The sky was exceptionally clear in the afternoon and I decided to go to PTC for stargazing. I loaded my Sky-Watcher HEQ5Pro in the boot. Luckily that the sky was still clear after diner. So I worked as a coolie and carried all the equipments, Equinox 80ED, C5, Porta, notebook, eyepiece etc, from my apartment to the car park. Due to the power cord failure last time, I did not try the HEQ5Pro. For saving my night, I carried the Porta, which works securely without electricity! Luckily, everything work beautifully last night!

This was really the first time, I tried out the HEQ5Pro. It was a strange mount for most PTC people because most of them are using LXD75 and Vixen mounts. After some people asking me about the HEQ5Pro without getting a proper answer, they just worked on their own task. I was kind of new in using such monster. First of all I don’t know exactly all the screws were all about. I needed to experiment by myself. It turned out that it was not difficult to get them work. Second but the most important thing is how to do the polar alignment. The manual was too simple that I cannot get much from it. I don’t have enough time to study the polar alignment from the Internet. Time is treasure! I simply put the Polaris at a point on the circumference of the circle inside the polar scope. It was a fast fix. As long as I am not doing deep sky imaging, all other task should be ok! Well! I loaded the Equinox 80ED on the mount and turned on the power and started to enter date, time, location etc. I used the 3 stars alignment, which supposed to be the best. After the “Alignment successful” displaced, I found the accuracy of HEQ5Pro was quite good. All the targeted objects are within the field of view of 8-24mm zoom eyepiece at 24mm. The HEQ5Pro was quiet during skewing compared with LXD75. The motor ran smoothly. However, the skewing speed seemed slower than LXD75. I needed to confirm this next time by a fair test. Anyway, I need to explore more before I can make a fair report on HEQ5Pro.

The foci of the night were the unbranded ED110 and the Maxvision’s Maksutov Newtonian 152mm. It was sadly that the focuser of the Maksutov Newtonian 152mm was defective and the scope was not properly collimated. No comment can be made. The unbranded ED110 was once again in high optical quality. Mirror God, a locally well known experienced stargazer, said that the ED110 beats the William Optics and price performance is real good! I deliberately compared the ED110 and my Equinox 80ED. Both scopes were set to about 200X and the target object was Jupiter. I found that both scopes delivered high contrast and color saturated image. The ED110 delivered a sharper image. It seemed that Equinox 80ED delivered a little bit higher contrast images. This was my own opinion and may be biased. I will invite the owner of unbranded 110ED to do fair test if possible. (Equinox 80ED: f=500mm, OR 6mm eyepiece, TV2.5X, Mag.= 500/6*2.5 = 208) (Unbranded 110ED: f:770mm, Takahashi 3.5mm eyepiece, Mag.= 770/3.5 = 220)

After playing around with the Equinox 80ED for a while, I parked the HEQ5Pro and mounted the C5 on it. But I don’t know why the HEQ5Pro forgot some of the location data and I needed to re-enter them again. Ahhh… Maybe Lewis, a friend of mine, pressed wrong button. Mysterious thing happen again! I cannot get the right sky model afterward! I needed to fix it by entering the time zone to be -8, which was supposed to be +8. Anyway, time is treasure again! I didn’t deal into detail. As it works, just forget about the reason. On the way back home I though the problem was again by Lewis. Maybe he entered wrong latitude and attitude data into HEQ5Pro. The data was a bit subtle that one needs to care about the East and West definitions. Blindly entering the numbers will just get it wrong. Anyway, I will confirm this and will not give Lewis a bad name if he is really good! Ha! Ha!

The C5 gave larger focal length and the Jupiter image size was much better than that of Equinox 80ED. I used the TV 2.5X as well. With the Porta for the same setting, I could only record about 10s. With the HEQ5Pro, I could record more than one minute. I didn’t try the time in fact because the processing time would be very long. I tried one minute and the final number of frame was 1200. The result is…

Planetary imaging

2009-07-14T08:03:00.000-07:00

After observed and shot Jupiter and Saturn several times with Equinox 80ED, I found that the 500mm focal length was not long enough for planetary imaging. The image on the sensors was so small! So I brought my C5 back home and tried to shoot Jupiter early this morning. The focal length of C5 was 1250mm. The image was much bigger. The result was not bad to me. One could see the color fringes of Jupiter. Since I am not familiar with RegiStax 5, I just use the default values and click the program until I get the final product! Better results can be achieved if I spend more time to play with RegiStax 5.

Saturn: 8-7-2009, 20:58, Tseung Kwan O, Equinox 80ED, Porta, ToUcam SPC900NC, 300 Frames, RegiStax 5, PS CS2
Jupiter: 9-7-2009, 5:36, Tseung Kwan O, Equinox 80ED, Porta, ToUcam SPC900NC, 300 Frames, RegiStax 5, PS CS2

About the image quality, although I used C5 instead of Equinox 80ED to do planetary imaging, it does not mean Equinox is no good. The prime reason was that a high power telescope is needed for such task. While waiting for my Meade 8 ACF, C5 is now the instant supplement. Well! Doing visual observation and astrophotography are different stories. The Equinox 80ED gives excellent visual images. I can see color fringes on the Jupiter and 4 satellites. The images are crispy, high contrast and saturated compared with those visual images on C5. However, when the image is projected on the webcam sensors, it was too small even TV 2.5X was used. So the simple solution to planetary imaging is high power telescope. I guess this conclusion is known to most stargazers. But I learned this by experiencing it!

During the observation, I tried to push the Equinox 80ED to limit. The target was Jupiter. The seeing was average. I used a 2mm eyepiece making the magnification to be 500/2 = 250X. The image was blurring, but acceptable. I could see the color fringes on Jupiter. By using the TV 2.5X, the magnification was boosted up to 625X. The image was garbage. It was just a blur disc! No details or color variation can be seen. Next I used the 8-24mm Zoom eyepiece and the TV 2.5X. The magnification at 8mm was 500/8*2.5 = 156X. Apart from dimmer image, the details and the contrast of the image were good. Pushing the magnification of Equinox 80ED to 200X is not a problem to me. (Note: The factory claimed the highest practical power is 160X.) Ah! This conclusion tempts me to buy the versatile TeleVue 3-6mm Zoom Eyepiece.

Jupiter: 14-7-2009, 5:19, Tseung Kwan O, C5, Porta, ToUcam SPC900NC, 400 Frames, RegiStax 5, PS CS2

Jupiter: 14-7-2009, 5:21, Tseung Kwan O, C5, TV 2.5X, Porta, ToUcam SPC900NC, 400 Frames, RegiStax 5, PS CS2

A busy observation day

2009-07-09T01:53:00.000-07:00

Moon: Equinox 80ED, TV 2.5X, D80, Prime Focus

Jupiter: Equinox 80ED, TV 2.5X, Sky-Watcher 8-24mm, Olympus C-5050, Afocal

The sky is exceptionally clear recently. Stargazing is my hobbit, but “family gazing” is more important. The compromise is home observation! Last night I shoot the Saturn. Early this morning I shoot the Moon & the Saturn. Since I am not familiar with Registax, I can only post the single shot here. I need to squeeze time to learn the Registax.

My new LS35THaDX

2009-07-07T06:33:00.000-07:00

Yesterday morning I got a call from Lunt’s local dealer that the adaptor for the LS35T was ready and I was welcomed to test its performance. In fact the first batch of LS35T was a prototype and was more expensive than the upcoming LS35T. But I decided to buy the special batch of LS35T.

Shortly after the launch of LS35T, people found that it was not webcam focusable. It was basically the optical tube or the focuser tube was too long. Lunt didn’t give resolution for the first batch of LS35T, but will rectify the upcoming LS35T. Since the modification is very simple, either make a shorter optical tube or a shorter focus tube will make it works. Maybe this is a cheap solution that to let the local dealer to make the modification rather than ship back all the scopes and modify those scopes by Lunt.

The reason I bought the first batch of LS35T was that it was not simply a deluxe package, LS35THaDX. The lens of the first batch of LS35T was made by Carl Zeiss. I was told due to the mass production problem; Carl Zeiss could not meet the Lunt’s specification with a reasonable low cost. So the upcoming LS35T will not use Carl Zeiss lens anymore. In addition, the blocking filter of this special batch was B600 instead of B400. So I treat this special Carl Zeiss batch or prototype as a collection.

Well about the performance, today we got a beautiful sunny day, I tested the LS35T. Recently the sun is very claim. I was very lucky that I saw two sunspots and one prominence. The locations of the two sunspots were around 4:00 to 5:00 and the location of the prominence was around 12:00. I could see the details of the sun disc. Since I don’t have PST experience, I can only compare the LS35T with LS100T and LS100F. It is not a serious comparison because I only have limited experience of LS100T and LS100F. At the moment, I am not able to produce any photos because I am too green in astrophotography. Getting the sun in focus in daytime is another challenge. Anyway, the image produced by LS35T is bright. Although the 35mm aperture is small, the solar disc is bright and uniform. I was told by a Solarmax user that Lunt’s image is very uniform and no observable ghost image is found. Don’t expect you can see the filaments at once unless you are using larger aperture or double-stack systems. You need to stare at the solar disc and inspect it carefully. However, once you get use to it, it is obvious! The details of solar disc can be improved by fine tuning the Etalon. This is what I have done today. I will try my best to take some photos soon!

As it is a low end product, it cannot be compared with my friend's LS100THaDS. However, I am sure you will not regret to buy one! It is affordable and handy. But the bad news is that the local dealer only got four special Carl Zeiss version LS35T. He will ship one to China and keep one for himself. The other two were bought by another stargazer and me yesterday. So all the scopes gone!

Afocal trial

2009-07-01T07:58:00.000-07:00

Today is a happy family day. After coming back from the Kadoorie farm, I took a wonderful shower. Ah…the half moon was just hanging outside my window. I used my grab-and-go scope, ETX-70, to do lunar observations. This was a good chance to test the Sky-Watcher’s 8-24mm zoom’s afocal ability. A friend of mine found out accidentally that after removing the eyecup at the back, it is a standard 42mm thread. I bought a 42mm to 52mm adaptor, which enables joining my good old Olympus C-5050 to the zoom eyepiece. The C-5050 has been sitting in the drawer for a few years. It is bulky, but its optics is good amount it’s class. That’s why I still keep it. It time for it to work again! The photo is a single shot. Is it OK to you?

ETX-70, Sky-Watcher 8-24mm zoom eyepiece, afocal, Olympus C-5050, BW, ISO200, F2.6, 1/200s

A day of sun & stars

2009-07-01T07:15:00.000-07:00

Yesterday was a fruitful day for me. I had solar observation with my students and stargazing at night. After the lunch, I found that it was possible to do some solar observations, although there were some clouds in the sky. I called up a few students to help me to bring the equipment to the school roof. I used the Thousand Oaks Optical Solar Filter Type 2+ and C5.

There was no sunspot at all. The image was flat visually as the filter was basically light reduction. After some visual observations, I tried to take some photos with my D80. I found that the image was so big that it was hard to be captured by the sensors.

However, I was in rush to leave the school. I have no time to try out the reducer. Anyway the photo was something like this. Before the arrival of my Lunt’s LS35TDX, I will use C5 and Thousand Oaks for most of the solar observations. By all means it is good for eclipse & planetary transitions.
After having the dinner and disciplined my daughter, I went out at about 9:30pm. When I arrived Pak Tam Chung, the half moon was pasted the zenith. Saturn was almost set. I didn’t setup my stuff at once, but browsed around. A friend of mind got a new toy, 110ED. He was busy testing his toy with other stargazers. Their focus was the moon. I shared with him my Sky-Watcher’s 2mm and 5mm eyepieces. These two eyepieces pushed the 110ED to 770/2= 385X and 770/5 = 154X respectively. The 2mm eyepiece definitely drove the scope beyond its maximum practical magnification. (i.e. roughly 110x0.04x50 = 220X). In term of visual, the performance is acceptable.
I just got a Porta mount and Equinox 80ED last night. It was because I need to spare my boot to carry stroller next day. Well I star tested by Equinox again. Both the diffraction spot inside focus and outside focus were round, concentric and symmetrical. The bright star was pin-sharp at the focus. Actually I just repeated what Mirror God told me last time. However this time I examined the diffraction spots carefully. One funny thing I found was that when I used a 2mm eyepiece on my 80ED, the image of the bright star cannot be focused to a spot but a diffraction spot with several Newton’s rings. Which means the image of a bright star become a quite large diffraction spot. The diffraction spot was still round and concentric. This reflected the Equinox is a good telescope. Lucky me! I will try to do the same test on other scopes and see if this phenomenon is general. It would be interesting that for those known famous telescope, if one pushes the magnification beyond its maximum practical magnification, what would be seen for the bright star image visually.

First formal astronomical photography, but....

2009-06-19T20:55:00.001-07:00

D80, 12-24mm@ 12mm, F5.6, ISO800, AWB

Being missed the excellent sky two days ago; I eventually came to Pak Tam Chung, PTC, last night. The sky condition is modest. I brought along with my equipment, Equinox 80ED, HEQ5Pro, Phillips Webcam, battery etc. This was the first attempt to use my own equipment to take some astronomical photos. In fact, I have taken some solar, lunar & stars photos before. However, this time I wanted to use my new HEQ5Pro to take astronomical photos with longer exposure. Finally it sucked due to the failure of the connection lead! The lead was originally soldered by me, but I cannot make it due to the size of the lead was too large to fit into the plug. My lab technician helped to solder it. The lead worked it lab, but sucked in PTC. I guess I must buy thinner size lead in order to make it work.
I was so frustrated last night, and chatted with other stargazers. You know what? I was so green that I only know a bit about the constellations. I can only recognize a few of them. Although I have “some money” to buy equipment, I am not familiar with the sky! It is ashamed that I have an MPhil in Physics, but my knowledge in astronomy is poor. I used to jeer at those owned Ferrari do not know how to drive. I am now owned astronomical equipment, but do not know the sky! I need to gear up myself!
I took some photos last night with ordinary photographic equipment. The AWB of D80 produced a dark sky. Perhaps the sky looks a little bit brown. This was mainly due to the light pollution in particular the artificial sodium lamps. In the third picture, I used Daylight setting in WB, the photo somehow reproduces the brownish color of the sky. So I learned a little about the WB in astronomical shootings.

D80, 12-24mm@ 12mm, F5.6, ISO800, AWB

D80, 12-24mm@ 12mm, F5.6, ISO800, Daylight

Try to config my Blog

2009-06-02T08:44:00.000-07:00

This is late already. I want to set up my own blog for some days. After looking at different blogs, Goolge is my choice. I did the registration and configured it for a while. Since I am running out of time, I try to make this post.