NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Mark 15 sextants
From: Roger W. Sinnott
Date: 2018 Oct 29, 15:07 -0400
From: Roger W. Sinnott
Date: 2018 Oct 29, 15:07 -0400
Thanks, Michael. The telescope on my EBBCO (which is 45 years old) seems excellent for its purpose. It is a Galilean type, about 2.5x, and I don’t see any chromatic aberration at all. My problem is definitely the filters.
Roger
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Michael Bradley
I've just bought an Ebbco, intending to use it as a class demo piece. . . .
The snag for me is the telescope itself - there's a lot of chromatic abberation. If all your shades appear to have 'gone off', it may be the telescope that's the root cause.
I've ordered a bit of 7/8" tube to make a sight tube, eliminating the telescope, I'll report back later ....
Good sailing
Michael Bradley
