the bigger the aperture is better, usually. You have to balance that with portability. If you don't use the scope, it's not worth it.<br /><br />Focal length is basically how strongly the mirrors/lenses focus the image. Longer is generally better.<br /><br />It's best to use an f-ratio of ~8 (give or take 1 or so) for beginners (IIRC, anybody else know?). The f-ratio is the focal length divided by the aperture (make sure to use the same units, inches, mm, whatever). This usually gives good naked eye observations, and higher and lower f-ratios serve better for astrophotography, or planetary observations...but 8 is midrange, so it does these all well.<br /><br />Btw, odds are you won't get into astrophotography for a long time, if you're thinking about it. And when you do, it'll be your 3rd or 4th scope, and you'll drop lots of cash on it then.<br /><br />A reflector just has light enter in the end, bounce of the back, go back up to the front, and exit out the side.<br /><br />A casegrain has the light go the same way, except that it doesn't exit out the side. It instead goes all the way to the back again, and exit through a hole in the main mirror. This allows a longer focal length telescope (usually considered "higher power" in a much smaller package (i.e. more portable or easier to build an observatory for)<br /><br />I typically recommend a 6-8" "dobsonian" reflector for newbies. A dobsonian is a reflector telescope stuck on a rotating mount, and can slew up and down. Very natural to use, very easy to set up. You take the base out (which is the rotating base) and put the scope on it. Try to be level (not really needed) and you're done with setup.<br /><br />The disadvantage (and advantage) is you have to point the scope yourself at objects, and it doesn't "track" so in a minute or so the earths rotation will cause the image to drift out of view. You can easily guide it by hand, but if you like showing things to friends a lot, you'd have to step in every other pers <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>
Basic Error: The accelerating Universe conclusion - reason
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