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
Distances.

Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To
Posted by Robert May on April 7, 2004 19:53:03 UTC

When you look at the problem, the secondary mirror needs to be far enough from the primary mirror so that the focus point is at the side of the tube somewhere. This then determines the diameter of the secondary as the diameter of the light cone (plus the FOV angle) needs to be fully or near fully reflected to the focuser.
Programs like NEWT25 (runs under windows) can do all of your calculatioins and the program is freeware readily available on the web.

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