OK here's the rest of my what qualifies as advice.
Telescopes, for amateurs at least, come in three categories: reflectors, refractors and compound telescopes.
First is refractors these are what most people of think of when you mention telescopes. Like this.
Refractors use a series of lens to focus the light.
There are two adjectives tossed around with this design, achromatic and apochromatic. Apochromatic refractors are designed to correct for an optical artifacts called false color. False color is a halo of light around a very bright object. Achromatic telescopes do not correct for this. Personally I fail to care most of the time. If however you are dropping big money on a refractor is better be and apochromatic one.
The upsides of this design is the usually give sharp images and are super easy to maintain. Also if you choose to use it to take pictures they are awesome for that as well.
The downside is larger sizes are very expensive. A 160mm Astro-Physics will run you about 9 grand for just the telescope without a mount. Of course there's a wait list to get on the wait list for one of these. No I'm not joking. Yeah there are cheaper options than the very best like Astro-Physics but they still are pricey.
Most of these telescopes come on an equatorial mount meaning one its axes is pointed at the celestial pole allowing the scope to easily track objects.
Reflectors are next type. Most of the commercial ones you see will look about like this.
The reflectors use two mirrors to focus the like.
This telescope is on what's called a Dobsonian mount. This mount is very simple and allows you to simply push the telescope all over the sky. Unlike equatorial mounts these are not aligned in anyway and don't track anything. However these mounts are very simple to setup and use and very rugged. They're kind of the Telecasters of the telescope world.
Upsides are that they simple to use and you can get a lot of telescope for not a lot of money.
The only real downside for this type is that occasionally you have to collimate the telescope, meaning you have to align the mirrors for the best performance. This is no worse than occasional guitar maintenance like keeping it in tune. So it's not a major hassle usually.
The last type is the compound telescopes which use both lens and and mirrors to focus the light. There are a few types of these out there but Schmidt Cassegrains are the ubiquitous ones and the what I will talk about.
The upside to this design is it is fairly compact and usually comes on mounts that can find objects and track them. These mounts rule for photography if you choose to do that.
Downsides are that any size larger than 8" weighs about as much as a 4x12 cabinet and the front lens, called the corrector plate, is very prone to dewing over if you have any humidity in the air. There are electronic and other fixes for the dew issue though.
Here are some good places to do a bit of research and some window shopping.
Orion Telescopes: Save on Telescopes & Binoculars! - Telescope.com
Stellarvue Refractor Telescopes
Meade Telescopes, Celestron Telescopes and Telescope Accessories - OPT Telescopes
Telescopes for Sale and Telescope Accessories at Telescopes.com
This is a really brief overview and really basic advice. Feel free to ask any questions.
