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The December 1958 issue of the Strategic Air Command magazine "Combat
Crew" has an article on precomputation of celestial observations:

"One of the drawbacks of present methods of precomputing celestial data
is the difficulty encountered in predicting the time the aircraft will
arrive at or near the precomputed assumed position ... the navigator may
find the aircraft is so far from the assumed position at fix time that
if he desires to use his precomputations, his intercepts may be too
large to permit accurate plotting."

https://books.google.com/books?id=JIRZn-7u2aIC&pg=RA17-PA24

If a round of sights are taken at other than the planned time, the
author says the solution is to adjust the assumed position east one
degree per four minutes early. Nothing else need be changed in the
precomputation.

The usual nautical practice is to reduce each body in a round of sights
with a different assumed longitude, selected to make its local hour
angle an integer. The assumed latitudes are the same integer value.
However, in the Combat Crew example the same AP is used for all three
stars in the fix. I've never seen that before and have not figured out
how the precomp is arranged to make that work.

Earlier I mentioned the B-47 sextant port at the copilot seat. I believe
the guy in the photo is using it. He appears to be under a bubble canopy.

--
Paul Hirose
sofajpl.com

   

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