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- From: raj@hpfcso.FC.HP.COM (Bob Jewett)
- Date: Tue, 15 Dec 1992 16:36:20 GMT
- Subject: Re: Telescopes?
- Message-ID: <9710048@hpfcso.FC.HP.COM>
- Organization: Hewlett-Packard, Fort Collins, CO, USA
- Path: sparky!uunet!cs.utexas.edu!qt.cs.utexas.edu!yale.edu!spool.mu.edu!sdd.hp.com!hpscit.sc.hp.com!hplextra!hpfcso!raj
- Newsgroups: misc.consumers
- References: <28562@oasys.dt.navy.mil>
- Lines: 33
-
- Well, I decided to post the first part of the FAQ from sci.astro here:
-
- 1. What is the single most important thing I should know before buy-
- ing a telescope?
-
- This is the single most important thing you should get out of this
- FAQ: DO NOT BUY YOUR TELESCOPE FROM A DEPARTMENT STORE. Ignore every-
- thing any literature tells you about magnification and such. Buy from
- a telescope store, where you will get a telescope that doesn't make as
- big claims, but will give you FAR better performance.
-
- The reason is that as far as telescopes go, how much you can magnify
- is a function of the amount of light the telescope receives, which is
- almost entirely determined by the telescope's aperture (the size of
- the lens or mirror that points at the sky). As far as magnification
- goes, you can expect 50x per inch of aperture on a normal night, up to
- 62.5x on an exceptionally clear night (this is the number Meade uses
- in calculating their magnifications).
-
- Department stores always show little 2 1/4 inch refractors for up to
- 300+ dollars and say that the refractor can get up to a whopping 600X
- or so. Strictly speaking, this is true. However, applying the 50x
- rule, it is easy to see that 125x would be pushing the optics, and
- that's assuming that they were high quality ones. With the quality of
- the parts they usually give you are lucky to get 100x with reasonable
- resolution.
-
- More details will follow. I put this up at the top so even if you
- read nothing else, you will read this.
-
- ------------------
-
- Bob
-