MIL-S-5807A Sextant, Aircraft, Periscopic
Kollsman Instrument Corporation
MS part no. MS 28011-1

©Brooke Clarke, N6GCE


Astrocompass Patent Drawing
Periscopic Sextant Mount Patent Drawing


Fig 1 Periscope in case
Fig 2 Label side
Fig 3 Elevation knob side
Fig 4 eyepiece side, upper left knob is bubble control
Fig 5 Close up of label and filter wheel & white knob cross hair lamp brightness
Fig 6 Warning label, clock winder & patent number
Fig 7 Elevation readout & clockwork dial
Fig 8 Cover page of Patent
MS 28011 Sheet 1 with part names
Fair Radio has a different one and the seal appears to be broken (see Fig 5 above for good seal)

General Information

This aircraft sextant was used for celestial navigation.  I think it has been replaced by GPS and/or inertial navigation systems.
The patent is dated 1945 and the sticker on the sextant is June 1986.  This instrument is a masterpiece of mechanical and optical engineering.

The bubble is there and can be controlled by the knob.

I think the idea is that the person sighting a star or the Sun, keeps it in the cross hair and at the same time keeps the bubble centered.
As the elevation control is moved up and/or down the clockwork mechanism is averaging the elevation over a period of time.

When the elevation dial is at 90 you are looking straight up and with it set for 0 you are looking at the horizon.  The smallest division on the elevation counter is 1 arc minute ( 1/60 of a degree).
Note you can only see out the periscope after the clock lever is pressed, winding the clock AND pushing the button to start the averaging.
How you get the averaged answer is a mystery.

I have not wanted to break the seal, but if you did I expect that the clockwork inside would be very interesting.
There are two GE 327 lamps easily accessed behind metal covers.

The Filter Wheel (Fig 5)  has 8 positions:  1= no filter,  2 = green, 3 = red, 4 = green+ND1, 5 = ND1+red, 6 = ND2+green, 7 = ND3+red, 8 = ND3+green.  The Neutral Density filters starting at no. 4 are strong enough that you can look at the Sun.  It's image is about the same size as the bubble. 

To hold the sextant some type of support would be helpful, like a 2x4 with a hole to clear the 1.375" diameter periscope tube and a way to keep it from falling out (maybe use the pin on the side of the tube?).  Unlike the sextants used on ships that are hand held, this one needs an external support.

US Patent 2516187 -Calculating Instrument application Feb. 24, 1945 covers some of the operation of this sextant. (see Fig 6 above)
The key feature is the "averager" that mechanically averages the elevation setting over time.

MIL-S-5897C(ASG) contains operational specifications such as:

3.3.1  Sextant.  Hereinafter, the term "sextant" shall be construed to mean the sextant proper, Periscopic tube, connecting cable, and watch clip.  The sextant shall be a bubble-type sextant built in the form of a periscopic telescope with the periscope projecting above the skin of the aircraft.  Provision shall be made for 360 degree rotation of the instrument around the vertical axis and tilt of the sextant up to 14-1/2 degrees minimum from the vertical axis.  The sextant shall conform essentially to Standard MS28011.
MS28011(AS) consists of three drawings: A.F. Manual 51-40 Air Navigation has a little information on this sextant.  Vol 1 has descriptive info and Vol 3 operational info

ID Plate

The ID palte reads:
Sextant, Aircraft, Periscopic
MS Part No. MS 28011-1
28 Volts A.C. or D.C.
Specification MIL-S-5807A
Mfr's Part No. 1471B-01
Mfr's Serial No. 3870
Order No. NOas 52-535
Stock No. R88S0400-050-000
Kollsman Instrument Corporation
U.S. Property  35050-1

And the paper sticker says:
Aerospace Guidance and Metrology Center (AGMC)
Repair Date JUN 16 1986
Newark Air Force Station
Newark, Ohio   43057

The label on the periscope tube says:
 
Minutes
   
-10
-1
-1
0
0
-.5
45
+.5
0
90
-2
-2

D-1 Mount

Perisocpic Sextant D-1 Mount in C-133
The sextant not only has an optical path that looks at the star but also a path that reads the azimuth from the D-1 mount.  The aximuth path includes provision to light the numbers on the mount.

The D-1 mount in the photo at left is in a C-133.








Patents

GB704644 Astrocompass and Adapter for Periscopic Sextant, Kollsman
2894330 Astrocompass, V.E. Carbonara (Kollsman Inst Co),Jul 14, 1959,  356/143 ; 356/147 - This looks like the S5807 Periscopic Astrocompass
Related:
2239790 Remote Indicator, P. Kollsman & V.E. Carbonara (Square D Co), Apr 29, 1941 - synchro?
2306684 Conductively Heated Pitot Static Tube, V.E. Carbonara (Square D Co), Dec 29 1942,
D114362 Design for a Shell of a Pitot Static Tube V.E. Carbonara (Square D Co), Apr 18, 1939
2225032 Thermionic Relay, V.E. Carbonara (Paul Kolsman), Dec 17, 1940
2262920 Illuminating Means for Instruments, V.E. Carbonara (Square D Co), Nov 14 19341 - lamp installs from panel side
2554010 Mount for Periscopic Sextants, V.E. Carbonara & E.D. McDonnald (Kolsman Inst Corp), May 22, 1951, -
3042296 Celestial Data Computer, V.E. Carbonara & E.D. MacDonald (Kolsman Inst Corp), Jul 3, 1962, 235/61NV - looks like the MD-1
Calls:
583518  Solar Attachment for Telescopes, P Stoller, Jun 1 1897,
1346412 Astronomical Instrument, E. Meitner, Jly 13 1920,
2077398 Navigating Instrument, J.C. Clark (Ludington Corp), Apr 20 1937,
2444933 Automatic Navigational Director, R.E. Jasperson, Jly 13 1948,
2508027 Celestial Position Indicator and Compass, P.E. Hoffmeister, May 16 1950,
2599381 Axis Converter, I.H. Gerks (Collins Radio), - parabolic dish
2724895 Navigating Device, P.E. Young, Nov 29 1955
2748485 Navigation Course Computer, W.H. Newell (Sperry Rand) Jun 5 1956,
2758277 Linear Phase Detector, J.I. Daspit (Gilfillan Bros), Aug 7 1956,
2762123 Navigation System, O.T. Schultz (Sperry Rand), Sep 11 1956, - uses photo multiplier tubes
2857672 Navigation System, D.O. McCoy (Collins Radio),  Oct 28 1958,
References:
2458654 System and Method of Utalizing Microwave Radiation from the Sun, G.C. Southworth (Bell Labs), Jan 11 1949 - Sun location through clouds for navigation
2672608 Automatic Tracking Mechanism, R.M. Ringoen (Collins Radio), Mar 16, 1954, - cloud tracking?
2599381 Axis Converter, I.H. Gerks (Collins Radio), - parabolic dish
Calls:
1845860 Navigating Instrument, E.J. Willis, Feb 16 1932,
2077398 Navigating Instrument, J.C. Clark (Ludington Corp), Apr 20 1937,
2444933 Automatic Navigational Director, R.E. Jasperson, Jly 13 1948,
2762123 Navigation System, O.T. Schultz (Sperry Rand), Sep 11 1956, - uses photo multiplier tubes

References:
2998529 Automatic Astrocompass, D.B. Nichinson & J.J. Connors (Kolsman Inst Corp), Aug 29 1961, 250/206.3 ; 250/203.1; 250/203.4; 250/207; 356/139.02
Calls:
2421012 Homing System, T.W. Chew (Navy), May 27 1947,
2541060 Tone and Density Compensating Device (Faximile Inc), F.A. Hester, Feb 13 1951, - photomultiplier tube
2713134 Radiant Energy Controlled Follow-Up System, H.J. Eckweiler (Kolsman Inst Corp), Jly 12 1955 318/575 ; 250/203.3; 250/203.7; 318/16; 318/489; 318/625; 318/640; 74/5.34 -
Photo multiplier El/Az mount
References:
2941082 Photoelectric Automatic Sextant, V.E. Carbonara, J.E. Manhasset, L.E. Sharpe (Kollsman Inst Corp), Jun 14 1960, 356/139.01 ; 244/3.18; 33/268; 356/148
Calls:
2444933 Automatic Navigational Director, R.E. Jasperson (Navy), Jly 13 1948,
2462925 Radiant Energy Directional Apparatus, R.H. Varian, Mar 1 1949,
2492148 Automatic Navigating Instrument, R.J. Herbold, Dec 27 1949,
2513367 Radiant Energy Tracking Apparatus, L.B. Scott (Sperry), Jly 4 1950,
2532402 Navigating Instrument for Craft and Pilot Guidance, R.J. Herbold, Dec 5 1950,
2533686 Gyroscopic Sextant, J.B. Peterson, Dec 12 1950,
2762123 Navigarion System, O.T. Schultz (Sperry Rand Corp), Sep 11 1956,
 Bendix A-15 Aircraft Sextant, probably made using the same patent

Links


History of the Sextant - page 2 with various aircraft sextants
Celestaire - Navy Mark V without AveragerNavy Mark V with Averager -
Garcia Avation - pricey
Deutsche Optik
Helmut Singer Elektronik - stock varies
JANS of London -InstrumentsSignificant events in the evolution of marine navigational instruments
Kollsman -has licensed Carp Industries. (CAGE 0D9X5) to mfg these systems.
CARP INDUSTRIES INC, 4550 U S HWY 1, GRANT, FL 32949
CAGE CODE: 0D9X5, Status: A - Active
DUNS Number: 194909032
Voice Telephone: 321-952-1303
County: BREVARD
SICs: 3728 Current List of SIC Codes
Date CAGE Code Established: 09/26/1988
Last Updated: 01/04/2001
Carp Industries - Kollsman out-of-production spare parts - Installation & Operation Instructions, Pub #S332C-300-961 dated 09/61 - Government type high prices

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