Telescope Buying Guide

Cullum Andrews asked:


My telescope needs a good dusting but I don’t want to scratch the mirrors and lenses. I have some sunglasses cleaner and the cloth that comes with it. At first this seamed ideal, but then it dawned on me that perhaps a the moisture can get between the lenses and fog up upon use also the mirrors can scratch from the cloth.

Simon Forsman asked:


i want to make one but i think that one i would buy would be more sturdy, i’ve searched for dobsonian telescope bases and nothing but thelescopes comes up, what should i look for? P.S. my telescope’s mirror is 130mm or 5″ but the tube is 6″, are the mounting rinds measured by the size of the mirror or the tube.

snail asked:


is it possible to build your own telescope? the larger the mirror the more light it gathers what about focal length? some advertise for example 10 inch mirror with f 4.5 what does that mean?

raul asked:


diameter of 8mm, how many photons per second could newton detect with the telescope compared to without? 8? 17? 33? 38? 1089? I believe it is 1089 i sqaured the diameter of each and subtracted
Assuming 100% reflectivity of the mirror and he used only one eye

screaming monk asked:


For a non-arrayed optical telescope, is there a limit to the size a mirror could be?

Vincent L asked:


I can’t find any good scope seller or an optical shop in our place that sells customizable mirror. I’m planning to buy a magnifying mirror and use it as a reflecting scope’s primary mirror. I’ve heard that the focal length might be short. How short is an average focal length of a magnifying mirror? Is it too short to be used in a telescope or passable as an average quality scope mirror? I haven’t bought one and measured it.