Post by curare on Jun 6, 2006 16:40:58 GMT -6
Hello All,
I just registered a few days ago and have been enjoying the site. I'm an extreme novice astronomer and am presently borrowing a Questar 3.5 (f/14) from the school where I teach. I would like to buy my own scope to use this summer. The two scopes I'm considering are:
A.) Zhumell 10" reflector (f/4.92)
www.telescopes.com/products/zhumell-10-inch-dobsonian-reflector-telescope-38399.html#
B.) Zhumell 8" reflector (f/8.7)
www.telescopes.com/products/zhumell-10-inch-dobsonian-reflector-telescope-38399.html#
So my main point of consideration is whether to go deep sky or medium range. I've been reading books on astronomy and telescopes, but book knowledge is no substitute for the experience that I lack. So I am hoping to pick your brains Here are some questions that are in my head:
1. The resolving power of the 8" is roughly twice that of the 10". By my reckoning, this seems to be a function of the aperture difference because both scopes have roughly the same focal length. Could applying a dimming filter (like a moon filter) to the eyepiece of the 10" increase its resolving power by decreasing the amount of light filtering through from the aperture? My concern here is that even though I am very interested in observing deep sky objects, I would hate to lose my ability to see the planetary detail I've been enjoying through the Questar.
2. My one complaint about the Questar is that even though the images are beautiful, they're small and it strains my eyes to look at an object like Saturn. The Questar has a maximum useful magnification of about 270x, whereas the 10" Zhumell has a MUM of about 600x. But what will the planets look like through the scope? Will they be blurry discs or will I still be able to see surface detail?
3. How will deep sky objects look different on the 8" and 10"? Does the higher resolving power of the 8" mean that I will be able to see more detail in distant nebulae? Or will the greater light collecting ability of the 10" give me that greater detail (as well as greater image size)?
That's it for now. After writing this, I'm figuring that since I have access to a high quality f/14 scope, I might as well go for the other end of the spectrum with the 10" f/4.92. I just want to make sure I'll see things with clarity and detail.
Thanks very much for any advice you can give,
Tim
I just registered a few days ago and have been enjoying the site. I'm an extreme novice astronomer and am presently borrowing a Questar 3.5 (f/14) from the school where I teach. I would like to buy my own scope to use this summer. The two scopes I'm considering are:
A.) Zhumell 10" reflector (f/4.92)
www.telescopes.com/products/zhumell-10-inch-dobsonian-reflector-telescope-38399.html#
B.) Zhumell 8" reflector (f/8.7)
www.telescopes.com/products/zhumell-10-inch-dobsonian-reflector-telescope-38399.html#
So my main point of consideration is whether to go deep sky or medium range. I've been reading books on astronomy and telescopes, but book knowledge is no substitute for the experience that I lack. So I am hoping to pick your brains Here are some questions that are in my head:
1. The resolving power of the 8" is roughly twice that of the 10". By my reckoning, this seems to be a function of the aperture difference because both scopes have roughly the same focal length. Could applying a dimming filter (like a moon filter) to the eyepiece of the 10" increase its resolving power by decreasing the amount of light filtering through from the aperture? My concern here is that even though I am very interested in observing deep sky objects, I would hate to lose my ability to see the planetary detail I've been enjoying through the Questar.
2. My one complaint about the Questar is that even though the images are beautiful, they're small and it strains my eyes to look at an object like Saturn. The Questar has a maximum useful magnification of about 270x, whereas the 10" Zhumell has a MUM of about 600x. But what will the planets look like through the scope? Will they be blurry discs or will I still be able to see surface detail?
3. How will deep sky objects look different on the 8" and 10"? Does the higher resolving power of the 8" mean that I will be able to see more detail in distant nebulae? Or will the greater light collecting ability of the 10" give me that greater detail (as well as greater image size)?
That's it for now. After writing this, I'm figuring that since I have access to a high quality f/14 scope, I might as well go for the other end of the spectrum with the 10" f/4.92. I just want to make sure I'll see things with clarity and detail.
Thanks very much for any advice you can give,
Tim