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    Re: Kollsman periscopic sextant mount AFNOA has 5 models of D-1
    From: Ronald P Barrett
    Date: 2010 Oct 27, 08:58 -0700
    Gary, Great work on D-1 sextant mount. AFNOA ( www.afnoa.org ) the USAF Navigators Observers Association just gave an entire rig like yours, made of pipe with D-1 mount, with good D-1,  to the Heritage Hall of the USAF/AETC Squadron at Pensacola... to remind the new CSOs who wear nav wings but never navigate.... where they came form! Chuckle. The young troops were quite puzzled as to how to look through a sextant. Wonderful fun.

    Interestingly here in AFNOA we have over the years sought and obtained Navigator items to parcel out to the flight museums. In the process I have seen and photo recorded that there were at least five different models of the venerable Kollsman D-1 sextant.

    I will get the photos off to you, going from the MA-1& MA-2 (Kollsman and held precedents) to the B-52 model that the EWO shot (as he was on the upper deck,,,, not the real navigator(s) who was/were down in the black hole) which had "NO-on-the-sextant-numerical-read-out.... the read out appeared on the MD-1 Display Panel converted to LAT LONG, Star Data,  Kollsmans Manf Part Number A2157C 00 004. At this point the nav did not have to compute LOPs as such. However the transport navs were still doing traditional celestial and plotting away!

    Side note:In the period of the two Hound Dog GAM days (1960s), the astro tracker on the Dogs were also were integrated into the MD-1 navigation system.

    Bob Harder the author of "BOMBING FROM THE BLACK HOLE", has done nav history a great favor in producing his book. Now if we can get more navs to write,,, there are surely more great stories out there.

    Ron Barrett, AFNOA President & Historian, 305-797-0745

    --- On Wed, 10/27/10, Gary LaPook <glapook@pacbell.net> wrote:

    From: Gary LaPook <glapook@pacbell.net>
    Subject: [NavList] Kollsman periscopic sextant mount
    To: NavList@fer3.com
    Date: Wednesday, October 27, 2010, 3:41 AM

    I just finished reading Flying From the Black Hole documenting the navigator's job on a B-52, which I heartily recommend. I decided to finally set up my sextant mount so that I could see what it was like to take sights this way. I have attached several photos showing the set up which I made with some two by twos and a round plywood disk. I provide the 28 volts for the lights by using a sprinkler system transformer, that's the little black box on top of the stand. Photo 6415 shows the top of the periscope extending above the fuselage (er, disk.)  Photo 6416 shows the azimuth crank with the azimuth readout window to the left of the crank. Photo 6417 shows the azimuth counter with the azimuth of the sun, 246.0° entered. Photo 6423 shows the power cable conecting the sextant to the mount. Photo 6428 is a view through the eyepiece showing the sun (through a green filter) near the left edge of the bubble. Below the bubble is the "inverse relative bearing scale" showing the hairline on 164.5° (I had trouble taking the picture through the eyepiece.) You set in the precomputed altitude into the sextant and you set the azimuth of the body into the azimuth counter and then turn the sextant until the aircraft's heading is under the hairline and the body will be in the field of view. By aligning the body with the hairline you can read out the exact heading of the aircraft and so provide a check of the aircraft compass' deviation. This is all the view a B-52 navigator would have of the sky so it was absolutely essential that the data be precomputed so the the sextant could be aimed in the right direction or else it would be almost impossible to find the star he needed to shoot. (My sextant mount was set up, randomly, on a heading of 165° True which I found out by lining up on the sun.)


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