Visit Lymax

Contents

Do Some Research

The Power Rip-Off

Wider is Better

Insist on 1.25"

Get a Solid Mount

1 Good Eyepiece

Department Store? NO!!

Do Some Research

(Yeah, I know that's what you are doing right now!) Very few people know enough about telescopes to assist you in choosing the right instrument. With so few scope-savvy people available, you will need to educate yourself to avoid being disappointed or getting ripped-off.

Avoid The "Power" Rip-Off

Power (magnification) is actually one of a telescope's least important specifications. Yet, most low-quality telescopes are advertised by stating a ridiculous maximum magnification. A good rule of thumb for maximum magnification is 50X per inch of aperture (diameter of the main lens). A typical 60mm refractor telescope is only useful up to 120X. Due to the immutable laws of physics, using powers higher than this is usually a waste of time. You can go into almost any department store and find a 625X 60mm Refractor. Run away! It is a piece of junk and you don't want it. Look for a scope with more modest, realistic claims.

Get the Widest Scope You Can Afford

The diameter (aperture) of the main lens or mirror is a telescope's most important specification and it controls how dim you can see, how deep you can see, and how much magnification you can use. Get a minimum of a 3" refractor or a 4.5" reflector. Anything smaller will probably be a disappointment.

Insist on 1.25 Inch Eyepieces

The American standard (and now world standard) size for eyepieces is 1.25". Specifically, we mean the diameter of the barrel on the bottom of the eyepiece that slides into the focuser. Most cheap, low-quality scopes use 0.965" diameter eyepieces. Why? Because they use less expensive glass and are cheaper to make. Also, since 1.25" is standard, very few good eyepieces are made in the smaller size. Bottom line: if it has 0.965" eyepieces, it is probably not the scope you want.

The Mount is as Important as the Optics

No matter how good the optics are, you can't get a good view of anything if the telescope won't hold still. If you are looking at the moon with 100X power, it means that everything is magnified 100X - the image of the moon, the movement of the earth, every tiny vibration of the telescope, every movement from a gust of wind, etc. No matter how nice the scope looks, if the mount is wobbly, you don't want it.

1 Good Eyepiece is Better Than 4 Crummy Eyepieces

Most good telescopes come with one good eyepiece. Quality eyepieces are relatively expensive. If a telescope comes with 3 or 4 eyepieces, be very suspicious. If the price doesn't go up with the number of eyepieces, then the quality of the eyepieces is going down. 1 good Kellner or Plossl eyepiece is worth a whole box of Huygens or Ramsden eyepieces.

Do Not Buy From a Department Store

For all of the reasons above, a department store is a bad place to buy a telescope. The telescopes available in most department stores are cheap junkers designed to hit a target price point and generate impulse sales. Control your impulses - you will be much happier in the long run.

Copyright © 2000 Lymax - All Rights Reserved