NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Index checks with laser and without
From: Bill B
Date: 2007 Jan 04, 17:49 -0500
From: Bill B
Date: 2007 Jan 04, 17:49 -0500
Alex wrote > But it does not help me much with stars index checks. > The stars I see are not exactly points, and brighter > ones look bigger. This could be a telescope problem > but more likely my vision problem. Another one of those shower moments.... What I believe we established is that the strong defraction spikes we use for measurement using Franks IE-check method are caused by the laser beam being split at the horizon glass and mirror junction. I do note, depending on which eye I use, I can get pretty near to a point source on the glass or mirror side. Better yet with eyeglasses. It is when I move the image to the center to split it that I get the tails and distortion. Is it possible the same effect as the laser spike are at work with a point source entering the system? The argument counter to this is that the defraction spikes produced by the laser run at right angles to the glass/mirror junction. Therefore a point source should have horizontal spikes with the sextant held in its normal position, which would aid in aligning the two star images. Also, my tails run at 45 degrees down from horizontal. Bill --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---