The Best Telescope

How important is the quality of a telescope?  To what extent does optical quality affect how much you can see and how well you can see it?  Provided that you don’t own one of those 2 inch in diameter, 600x refractors, advertised by some discount department stores, telescope “quality” is vastly overrated.  Other factors are much more important.

1. 
   1.The transparency of the sky.  This one is obvious.  If it’s cloudy, you can’t see anything.  And even a slight amount of haze makes a huge difference when you are trying to observe faint objects.
   
   

2. 
   2.The amount of light pollution at your observing site.  To see many faint objects well (or at all), there must be sufficient contrast between them and the background sky.  That’s why many catalogs of deep-sky objects list the “surface brightness” together with the overall magnitude.  Even bright objects don’t show up very well when that brightness is spread out over a large area.  Light polluted skies (or moonlit skies) drastically decrease the amount of contrast between object and sky.  
   
   

3. 
   3.The “seeing” conditions.  Even when the sky is very dark and clear, the atmosphere is often “unsteady.”  The stars twinkle beautifully, but planetary images look like quivering mush.  Increasing the magnification only increases the fuzziness.
   
   

4. 
   4.The experience of the observer (you).  You have to learn how to “see.”  It takes patience and practice.  Some people have difficulty seeing anything through a telescope.  Your eye has to be positioned correctly, you need to relax, and sometimes you have to wait for a brief moment of excellent seeing.
   
   

5. 
   5.The quality of your eyesight.  Near-sightedness and far-sightedness are not a problem (just adjust the focus), but astigmatism, the size of your dilated pupil, and the presence of “floaters” are all a factor.  At my age (63), objects no longer look as bright or as sharp as they once did.
   
   

6. 
   6.How precisely are the optics of your telescope collimated?  Usually not a problem for refractors, but definitely important for Newtonians and Cassegrains.
   
   

7. 
   7.Ok, now we finally get to the quality of your telescope.  How precisely have the mirrors and lenses been figured?  Are the eyepiece lenses well coated to prevent internal reflections?  How steady is the mount?
   
   

90% of the time you’re not going to be limited by the quality of your telescope.  Other factors almost always play a much larger part.  Most importantly, does your telescope get used?  Quality doesn’t matter at all if the telescope stays in a closet.