NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Testing Scopes
From: Bruce Stark
Date: 2006 Apr 16, 23:49 EDT
From: Bruce Stark
Date: 2006 Apr 16, 23:49 EDT
Alex,
To get past that problem of the various shades when measuring index error with the sun, I cobbled together a shade that slips onto the objective end of the inverting scope. It's made of half of one of the shades that fit in an arc-welding hood. That and a plastic bottle. The shade is a gold-coated # 12. Just right for comfort, and it gives you a wonderfully clear, sharp-edged sun. It's made of polycarbonate, so adds nothing to the weight of the scope. The down side is that the reflective gold coating would be easy to scratch.
I think this shade would be useful in your precision testing. If you'll give me your postal address I'll send it along. I have the other half of the welding shade and the tube of glue. By the time I'll be using a sextant again I'll have another plastic bottle. The only difficulty in cobbling one of these things together is finding a bottle the right size and a glue that sticks.
Bruce
To get past that problem of the various shades when measuring index error with the sun, I cobbled together a shade that slips onto the objective end of the inverting scope. It's made of half of one of the shades that fit in an arc-welding hood. That and a plastic bottle. The shade is a gold-coated # 12. Just right for comfort, and it gives you a wonderfully clear, sharp-edged sun. It's made of polycarbonate, so adds nothing to the weight of the scope. The down side is that the reflective gold coating would be easy to scratch.
I think this shade would be useful in your precision testing. If you'll give me your postal address I'll send it along. I have the other half of the welding shade and the tube of glue. By the time I'll be using a sextant again I'll have another plastic bottle. The only difficulty in cobbling one of these things together is finding a bottle the right size and a glue that sticks.
Bruce
