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    Re: MK2A periscope sextant
    From: David Pike
    Date: 2020 Dec 24, 13:50 -0800

    Thanks again David for the advice. Sould be easier when I get the battery pack made up. I presume from the picture title that's a Victor.  Must have been pretty difficult wearing all that equipment . My 2A was last used on a Hercules which is a surprise as I'm sure the last one I flew in had an astrodome.

    I put the photo in because it shows someone using a Mk2A sextant in a Victor.  Judging from the flying suit it was probably taken in the late 50s or early 60s.  You can see it’s a Mk2A sextant because of the swivel eyepiece.  When you look how close the chap’s head was to the cabin wall, you can see why the swivel eyepiece was necessary.  In the Vulcan we used the Mk2 Bubble sextant or the Mk2B Pendulous Reference sextant, both of which had fixed eyepieces.  I’ll try and find out if the Victor had one or two mounting holes.  The Vulcan had a hump behind the pilots, which contained the multi seat dinghy, so we had to have two mountings, one either side.  This was quite good because you could draw a second sextant from Ops and mount one either side.  Then you didn’t have to keep moving the sextant from side to side between stars. 

    I suspect the photograph was probably a publicity snap taken on the ground, and the chap might not even be the Navigator-Radar.  The sextant is probably wound up, but it’s not running, because the averager is reading 0 00, and the azimuth is set to 360 (could be a Polaris shot I suppose).  Moreover, his right hand should be on the right-hand handle with his thumb on the index mirror adjusting wheel.  Finally, he’s got his watch on the correct way round.  An experienced Smiths, Kelvin, Hughes sextant user would have his watch turned around so that the light beam from the bottom of the right handle would light up the face of his watch when he pressed the button on the left handle.   I bet you’ve not noticed that little light outlet yet.

    I’ve only been in the front of a Hercules once in 1968, and once in the back in 1975, so my knowledge is limited.  However, as I understand it, all KC130s, have an escape hatch on the port side of the cabin roof.  When the Hercules was on order for the RAF in the mid-1960s, someone, in their wisdom, specified that this should also include an observation cupola, and the aircraft were so delivered.  Eventually they were taken out, because they weren’t used much, some were delaminating, and there was the ever-present worry of an explosive decompression at altitude.  Then, in the 80s, when the aircraft began being used in more hazardous tactical situations, it was decided it would be rather nice to be able to have a better view above and behind, and a new set of improved cupolas were ordered and made available.  I don’t think they were ever used for sextant work.  The aircraft must have a periscopic sextant mount in the cabin roof somewhere, but I’ve no idea where it is.  DaveP 

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