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
Focuser Drawtube Length

Forum List | Follow Ups | Post Message | Back to Thread Topics
Posted by Dave Sellors on April 17, 2003 16:09:58 UTC

Hello:

I'm building a 10" dob, with a custom made crayford focuser. My question is about the optimal length of the focuser drawtube.

My concerns are that too short a drawtube invites stray light into the eyepiece (poor image contrast ?) and too long a drawtube could block incoming light when the focuser is close to being totally racked in (vignetting?). If I'm understanding these issues properly, how should I choose how long to cut the tubing ?

Dave

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