NavList:

Dave,

I appreciate your comments. Let me take a few of your points and make sure I understand what's happening. I also attach a diagram of one of the standard Kollsman setups to be sure we are talking about the same device.

You comment  3.  There’s only one rose/disc.  The set heading knob is geared onto it.  If you look at the bottom of the mounting, there’s a window showing a portion of the azimuth disc and a little arrow pointing towards the disc.  If you wind the set heading knob until 000.0 appears in the heading window on the mounting, the little arrow on the mounting will be pointing towards N on the disc. 

If there is only one rose, how does the Azimuth Counter (result of using the crank) show something different than the rose in the view finder. Note in the attached image, 244.5 is Cranked in and 50 shows in the finder. To me, this suggests two roses (if you consider the Azimuth Crank turns a form of a rose).

Point 4 seems clear. The eye piece is to the 'rear' of the periscope.

You comment  5. So, assuming your mounting is fitted in the aircraft correctly, i.e. With 000.0 set in the heading window, the centre of the fin corresponds with an azimuth of 180, you find your star as follows.  Set the aircraft heading in the set heading window.  Set Hc on the sextant.  Swing the sextant until the star’s azimuth appears on the azimuth disc visible though the eyepiece.  And there will be your star (plus 3 or 4 dimmer ones, but the pictures in the Air Almanac tell you which is yours).

The heading window? This term is not in the references I see but you may mean it's the heading in the Azimuth Counter? Yes?

On Point 6, I can not comment on because I don't know what is the 'azimuth window' or the 'heading window'

I'm not there yet but it's getting better and I appreciate the push here.

Ed

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