NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2015 Oct 4, 03:48 -0700
Hello David, Pink desiccant packs (moisture crystals) are saturated and should be re activated (blue = good). Most re activation processes involve heating. A search on the www will find you the process for the packaging that you have. Tom
But, unless you are planning to use your sextant in the stratosphere, it is nothing to worry to worry abut. gl
Gary. Are you saying that flying in the tropopause there’s a chance of the sextant getting down to the -50 degrees C or so which the manual suggests might cause fogging? I operated with the Smiths sextants up to FL470 and never encountered any problems even on the rare occasions when I forgot to switch the mounting heater on or left the sextant up between sessions. I think it was because most of the sextant is still inside the aircraft, and there’s heat conducted along the aluminium periscope tube. There’s also probably a couple of degrees temperature rise due to kinetic heating of the head and, in daytime, about one degree rise from radiant heating by the Sun (I suppose its opposite at night). Whenever I replaced the sextant in its case, I don’t recall the tip feeling particularly cold. Thank you for the print-out of the manual. It explains the original use for some of the unused threaded holes. It will go with my Kollsman bubble manual. I didn’t realise Kollsman had a pendulous model as early as 1956. DaveP
