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Aug30-04, 08:05 PM
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Quote Quote by Chronos
At 200x Jupiter will appear to be about the size of a half-dollar held at arms length. Saturn will be about a third that size. Neither image will be very clear except on nights of exceptional seeing. Cold, still nights give the best views. See link for some views I consider very representative of what you could expect to see through an 8" telescope under decent seeing conditions.
That's a pretty good site, Chronos - at least for the extended objects. You are right about the cold still nights. If those nights are good for visual observing, they are great for astrophotography. Here in Maine cold still nights usually result in temperature of 10-20 degrees below zero or colder, and those are the nights that are the very best for astrophotography. Now imagine holding absolutely still for 20-40 minutes or more and staring into the ocular of your guidescope, keeping the guide star centered. Can you imagine being happy and comfortable while doing so? I can. I have cloth Air Force arctic type flight-line boots in size 13 with two sets of nesting felt liners (my feet are size 8), and I have many layers of fleece, goose down, etc, with windproof nylon at the perimeters. I weigh only about 150 lb, but when I suit up and put on my big Russian Army rabbit-fur hat with ear-flaps, I am way less attractive than the Michelin man, but similar in proportions. I can stay out all night in those conditions with no problems.

For astrophotography in nothern climates, dress like are going ice-fishing all day, then put on twice as much down and fleece as you think you might need, and quadruple the protection for your feet. You'll be fine. When your feet are aching, and you're shaking all over, you cannot guide a decent astrophoto.

The original poster asked for realistic expactations about the appearance of planetary object in high-power views, and I have strayed off the course. I should add that realistic, satisfying views of planetary objects have a heck of a lot more to do with using a VERY accurate telescope - might I suggest an apochromatic refractor or a very well-figured reflector? I have not yet looked through any 10" commercial Newtonian reflector or Schmidt-Cassegrain that can rival the planetary views through my 6" Astro-Physics APO. I am pretty sure that there are some well-figured 10" newtonians or S-Cs that can blow my scope away. I haven't bumped into one yet though.