NavList:

Hi Josh

Yes there are a few of us air force navigators on this forum but in general ( except for the USAAF) methodology for commonwealth air navigation was inherited from RAF Flight Manuals.

My flying was done in the RNZAF - on Bristol Freighters and then on P3B Orions. Whilst it has been some decades since I did a astro shot in an RNZAF aircraft, I still have my RAF Air Navigation manual and all my folders and preforma but the process is rusty at best - though I do remember methodology. 

The Bristol Freighter had an astrodome and we used the standard Mark IX bubble sextant to shoot astro - yes we pre-worked our astro shots using the 3 volume 249 pubs. The Bristol Freighter was exactly what we learnt from Navigator training done on Devons using Mk IX bubbles and astro-domes. The Bristol Freighter was not pressurised and had a ceiling of 10000 but we roamed far and wide across the south pacific in these big ugly machines, typically island hoping.

The P3B Orion was a completely different machine - it was pressurised with a ceiling of around 32000 ft and we flew everywhere night and day that civil aircraft do not go.

The sextant was a periscopic bubble Kollsman - same principle as Mk IX - just a little more sophisticated and periscopic because it needed to be ablle to poke its nose out of a pressurised hull and not ice up at 32000 ft where temps can be -60 C ..... Also the field of view was very narrow so you had to calculate shots to specific times so that you didn't have to hunt for the star when it came time to shoot - an advantage of the MK IX is you could look for a star - get it in the sextant view - shoot and then work out the shot later.

One thing I had that I think was unique in the RNZAF certtainly was I bought the 1st hand held computer on the market - a Texas Instrument with card reader and I put all the relevant latitude info from the 249 tables on mag cards and read them into the hand held calculator and could calculate a pre-shot in 30 secs ....... the problem with pre-computing was that the 3 stars you picked might not be visible at the time of the shot - with the handheld I could decide at the time - which star - shoot it - pick another star 120 deg or close apart - shoot that then another 120 degs apart and shoot that then do the pre-calcualtion within about 1 - 2 minutes ...... reason - we didn't always fly in clear air at that height and high sirrus cloud could be enought to obscure a low illum star.

I have bought all the gear and books to resurrect my astro skills but just haven't had the time to do it yet as I am in full time work still at 74 years. I purchased a refurbished USAAF bubble sextant which I yet to use in my resurrection of astro skills.

Howard G