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From: freeman@spar.UUCP (Jay Freeman)
Newsgroups: net.astro
Subject: Re: To buy a telescope.
Message-ID: <336@spar.UUCP>
Date: Tue, 18-Jun-85 13:14:52 EDT
Article-I.D.: spar.336
Posted: Tue Jun 18 13:14:52 1985
Date-Received: Sun, 23-Jun-85 11:42:08 EDT
References: <894@sdcsla.UUCP>
Reply-To: freeman@max.UUCP (Jay Freeman)
Distribution: net
Organization: Schlumberger Palo Alto Research, CA
Lines: 42

[]

In article <894@sdcsla.UUCP> wargo@sdcsla.UUCP (Dave Wargo) writes:

>I am in the market for a telescope. Nothing fancy.

Try some books for detailed advice, or perhaps a local astronomy club.

>My questions are:
>
>1. What does the diameter have to do with power? 
>   Or are they two different things?

For astronomy, more diameter is better because it means you can gather more
light and see fainter objects.  Furthermore, the amount of detail in the
image is set by the diameter of the incoming beam of light (bigger means
sharper image with more detail).  You can use any magnification with any
telescope, but after you are using enough power to see all the detail that
there is in the image, more power is useless.

>2. If power and diameter are not directly related can I get a 4"
>   scope and change the power by changing the eye piece?

Yes, but if your eyesight is typical, a power of about 200 will show all the
detail there is in the image, so there's no point in using more.

>3. What size should I get for general viewing?

For astronomy, as big as you can lug around and set up -- reflectors above
twelve inches in aperture are sometimes a pain to handle.

>4. How much should I pay?

Get a copy of the magazine "Sky and Telescope", and browse in the ads.
Three or four hundred dollars will buy a fine ten-inch reflector.

>5. What should I look for in a reflective scope.

Optical quality, portability to suit your needs, mechanical stability
(mostly freedom from vibration and jiggling), not too many gadgets.

-- 
Jay Reynolds Freeman (Schlumberger Palo Alto Research)(canonical disclaimer)