Back to Home

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
Login
Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place...
The Space and Astronomy Agora
RE: Chooseing The Proper Focal Length

Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To
Posted by Jack McQuaide on September 5, 2000 03:09:25 UTC

Heya!

There really is no "proper" focal length. You can make the focal ratio (f/5=40", f/6=48", f/7=56" etc) to just about whatever you desire. Take into consideration, that the higher ratios will make the length longer, and a larger scope. The lower ratios will make a shorter scope, but are more difficult to finish the mirror. The most common would be an F/6 to F/8 mirror. The longer focal ratios lend themselves towards planetary scopes, while shorter ratios are for deep space objects.

Wookie

Follow Ups:

    Login to Post
    Additional Information
    Google
     
    Web www.astronomy.net
    DayNightLine
    About Astronomy Net | Advertise on Astronomy Net | Contact & Comments | Privacy Policy
    Unless otherwise specified, web site content Copyright 1994-2024 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