The popular Schmidt-Cassegrain telescopes (SCT) are mass-produced. This design lends itself to the production of good telescopes on a large scale. However, they are not hand made, and you can never be certain of their optical quality. This applies to all brands. If you have an SCT, it is a good idea to take it to your local astronomy club and ask someone who is experienced in the making of telescopes to test it. If this is not possible, then just jump in and try it out. You will soon find out for yourself whether you have an onion or an orchid!

When using refractors and SCT's: do not use the diagonal mirror (right angle eyepiece attachment) that the manufacturer supplied. These are invariably of poor quality. Look straight through your telescope if you want maximum image quality. This will be rough on your neck, but will do wonders for your telescope's imaging ability.

If your telescope does not seem to be performing to the level you expect, all is not lost. First try using a different set of eyepieces. The eyepieces that are shipped with commercial telescopes are frequently of poor quality. Try some eyepieces in the medium-price range. They should give better results. There is no need to invest in the super-duper eyepieces that cost more than some telescopes. For planetary work simpler is better. Kellner, orthoscopic or Plössl eyepieces are fine. This suggestion is appropriate for all types of telescopes.

If you are using a Newtonian reflector, and it doesn’t seem to give really sharp images, try replacing the secondary mirror. (Check Sky & Telescope magazine for suppliers.) If this doesn’t work you may need to have your primary mirror refigured. This is the most expensive corrective action you can perform, but it is far less expensive than buying a new telescope. Before sending the mirror off for refiguring, have it checked out by someone in your local astronomy club who is an amateur telescope maker.

One final piece of advice: never use variable power eyepieces or variable power Barlow lenses. They always degrade the image. If you want to use a Barlow lens, check with one of the section coordinators for advice on purchasing a really good one.