Thursday, January 27, 2005

The First Night with the Ranger in CUHK

The condition was not very good when it's 6:00p, and it seems to be hopeless. I had taken my scope to school and I guess it would be wasted.

When it's 7:15p, I went up to the roof to have a look. Woo! It's full of stars. The scorpius was still there, but when I looked at the heart of the scorpius, I noticed that the air was not so steady, since the red star was twinkling. Anyway, it's already one of the best night for observation after getting my Ranger.

What a complete falure was that, I had forgotten to plan my observation. There were lots of stars in the sky, but I had no idea about what I was going to point my scope at. I tried to find the double stars in the scorpius, but I failed to find them, since I've forgotten exactly where was it. I tried to locate the Andromeda Galaxy, but I failed too. I tried to locate the Saturn, and again, no luck. (Finally, I checked later and realized that it's not yet in an observable location.)

Finally, I've looked at the moon, which was more than a half-full. The view was nice in my 6.3mm Celestron Plossl Barlowed, and it was better than the last time I saw, the boiling water effect was not very apparent. It reminded me for the last experience, which gave me a feeling that I was flying inside a space craft, looking outside the windows. Next, I've tried to look at the Jupiter, and I could pick out the two dark bandings with the 20mm Tele Vue Plossl, while my little sister said that she couldn't. Maybe that's experience.

Then, I tried to use the 6.3mm Celestron Plossl Barlowed, yielding 152x and I could see one more banding, at least. Two thicker ones and one thinner lying near on the outer side of one of the thicker bandings, were what I saw, excellent. I wish that I could see the GRS next time.

Last time, I found that I simply couldn't put the three Galileo satellites into the field of view of the 6.3mm Plossl Barlowed, however, I later realized that it's due to the insufficient eye-relief of the eyepiece, so that I've to put my eyes real close to the eye lens to take into the whole field of view. I've tried it out and I found that I could now put everything of the Jupiter into my eyepiece! It's a good and new discovery. This time, I found that the 6.3mm Celestron Plossl was not as bad as I once thought, except the short eye-relief. It seems that my next move should be getting a higher power barlow (the Powermate?) and a longer focal length eyepiece, say a 12mm and to use them together as a replacement of the 6.3mm, so that I can have more eye-relief. Or another alternative is that, to get a wide-field eyepiece, which requires a lot more money.

Lastly, I've found a nice point of refractors (un-obstructed scope) and that's a darker sky and brighter stars. I've also found a weak point of (non-APO) refractors, it's the chromatic abberation problem in brighter stars. However, I found that it's not a problem for extended objects like the Moon and the Jupiter, however, it's obvious in the real bright stars. And I found it nice to use higher magnification for brighter objects, since the view would become dimmer so that I can pick up more detail. But does it implies that I don't need those (color) filters now?

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