Happy Halloween

ATM Forum Message

Forums: Atm · Astrophotography · Blackholes · Blackholes2 · CCD · Celestron · Domes · Education
Eyepieces · Meade · Misc. · God and Science · SETI · Software · UFO · XEphem
RSS Button

Home | Discussion Forums | Amateur Telescope Making | Post

Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place...
The Space and Astronomy Agora
8" Mirror Choice

Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To
Posted by Jarvis Krumbein on June 2, 2004 15:45:10 UTC

Go with the f5.6 mirror. There are several reasons. First, unless you want to spend a small fortune on eyepieces, the f5.6 will work well with the commonly available (and reasonably priced) Plossel types. Unless you opt to spend lots on some of the Nagler or other pricey wide field types, there is no advantage to the f4. Second, you can use a smaller diagonal with the f5.6 so the obstruction loss will be smaller. Third, the f5.6 will collect as much light as the f4 and the contrast will be slightly higher (the sky background will be darker).

There are more reasons but these are enough to help you with your decision.

Jarvis Krumbein

Follow Ups:

    Login to Post
    Additional Information
    Web www.astronomy.net
    About Astronomy Net | Advertise on Astronomy Net | Contact & Comments | Privacy Policy
    Unless otherwise specified, web site content Copyright 1994-2021 John Huggins All Rights Reserved
    Forum posts are Copyright their authors as specified in the heading above the post.
    "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET"
    are trademarks of John Huggins