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: Testing An Hyperboloid Convex

Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To
Posted by Jarvis Krumbein, jkrumbein@juno.com on June 19, 2000 19:18:50 UTC

The easiest method uses a Hindle sphere as described by Texereau. It is not necessary to have a sphere as large as or larger than the primary will be nor is it necessary to have a radius of curvature equal to the focal length of the primary. Almost any fast reasonably good sherical mirror can be used and it need not be perforated. The method requires that the sphere be offset and tilted so that the RC of the sphere coincides with focal point of the primary of the finished system. The cass secondary is then examined with the light passing at the edge of the sphere. You can examine only half of the secondary this way but assuming that the curve is regular and does not have any astigmatism this is adequate. This works for a conventional cass. The spacing needs to be modified though if a Ritchey secondary is being figured as the conjugates of the hyperbola need to be adjusted.If you need more info, feel free to contact me via e-mail.

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 1994-2021 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