Reprocess the 28-11-2009 Lunar Mosaic

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

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

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!
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

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

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

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.