A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2017 Aug 26, 02:56 -0700
Will my wife be wasting her money if she buys me an A12?
David. LED street lights are pretty bright, witness driving towards cars with such lights. We’ve got a particularly bright one on the main road west of us. We’ve a sodium one outside our house, and I think I find the orangeness more annoying.
Light pollution plus a dirty old light path is a problem with any aircraft sextant used on the ground. I can’t see the A12 being any worse than any other aircraft sextant. In fact, it might be better than most, because it had such a direct light path being reflected only once off , or observed through, glass and that’s it. http://fer3.com/arc/imgx/A-12-sextant-manual-part-1.pdf I have to admit that I’ve never tried my A12 at night, but I’ll have a try first clear night we get. It won’t matter that I’ve yet to find a bubble, because you’re only want to know if you can see the stars. I can just about see bright stars through my MkIXs, but observing Polaris requires a lot of imagination.
Mitigating techniques might be: observe only the brightest stars; persuade your Council that they can save money by turning off the street lights after ; operating from the shade of a suitable building; take your A12 somewhere where there’s less light pollution. The A12 plus its case would be particularly good in this last respect, because it’s probably the smallest, lightest, least knee bruising aircraft sextant available. You could carry it in your car plus a celestial app like ‘Navigator’ on your smart phone or net-book, and operate whenever an opportunity presented itself. DaveP