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
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