How to collimate a telescope
Here is advice on how to make sure the mirrors in your telescope are properly aligned to give you perfect views of the stars and night sky.
Here is advice on how to make sure the mirrors in your telescope are properly aligned to give you perfect views of the stars and night sky.
Another test for your telescopes, using a bright star, which is much more difficult to carry out.
A series of simple checks which you can carry out for yourself on a clear night, and which should at least tell you how good your telescope is, plus where any faults lie.