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

Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place...
The Space and Astronomy Agora
Ronchi Gratings

Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To
Posted by Robert May on October 31, 2002 21:07:00 UTC

You don't need a Ronchi Grating for making a Foucault tester. You just need a razor blade for the purpose.
You may want to stop by my website where, on one of the subpages in the mirrormaking article, testers are commented on. .
Ronchi gratings are available from a number of places from Edmund Scientific to Willmann-Bell amongst others.
One of the early methods of making a grating was to take fine copper wire and wrap two strands between two copper or brass rods in a frame and remove one strand of the wire and then solder the other wire to the rods. Then remove the second side of the wires and use this as a grating. The spacing will be that of the wire size. The better way now is to print or etch the lines on a piece of glass or plastic or make a photograph with fine quality B&W film, depending upon the desired size of the spacings.
If you desire to make gratings with film, make sure that you get the spacing even and the lines 50% wide.
People have done gratings with printers but often have problems with uneven spacing due to the software that is normally used interpolating the spacing and putting down 10 dots on one line and 11 dots on another line, making the grating useless for optical work.

Follow Ups:

    Login to Post
    Additional Information
    About Astronomy Net | Advertise on Astronomy Net | Contact & Comments | Privacy Policy
    Unless otherwise specified, web site content Copyright 1994-2022 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