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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sextants with Polarizing filters
From: George Huxtable
Date: 2006 Jan 27, 00:01 -0000
From: George Huxtable
Date: 2006 Jan 27, 00:01 -0000
On 24 Jan, Peter Fogg posted the following- "On the certain range: each polarising filter reduces the brightness of light passing through by about one and a half f/ stops, or 150% (this varies between manufacturers; 150/200%). So two used together would already have quite a significant minimal darkening effect, which could be halved by using only one." He doesn't appear to have withdrawn it since, although it has been questioned, and was contradicted by Bill's numerical observation. Perhaps he will tell us whether from that, and from the recent web reading he has told us about, he has since changed his mind. George. contact George Huxtable at george@huxtable.u-net.com or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
