Re: [ATM] My scope

[Mark Holm <mdholm@telerama.com>]

Gerald Clay wrote:

> BTW it's an 8" mirror.  What focal length would be good for viewing the planets and deep sky images?

Focal length isn't so critical a variable as you might think in 
observing performance.  Under f/5 gets to be more difficult to figure. 
In an 8 inch, over f/8 gets to be a fairly lengthy package if built as a 
one piece tube.  Eight inches isn't really big enough to warrant a truss 
or other fancy knock-down design unless you really have a need for 
compactness.  Many experienced observers with larger telescopes keep a
6 - 10 inch, solid tube Dob around specifically because they can carry 
it out of the house and be observing in a minute or two.

If the planets aren't big enough, and the mirror is good enough to make 
the higher magnification usable, treat yourself to a shorter focal 
length eyepiece in addition to the 25 - 27mm or so that you should 
probably start out with.

-- 
Mark Holm
mdholm@telerama.com

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