Lunar Image Taken with Equinox 66ED

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

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:
“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

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

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

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.