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    Re: Bermuda to St Helena on a North Atlantic Mercator Chart
    From: Howard G
    Date: 2021 Dec 30, 16:00 -0800

    Hi David

    I know what you mean - my maths knowledge rusty but understanding of the 3D and 2D vectors I did university courses during flying in RNZAF - and have maintained my mathematical skillset with high level computer coding and still do - skilling up now on the latest Visual Studio VC#.NET - OOP language.

    Interestingly - from my twin brother - who is a senior line captain Air New Zealand - was on 777 but now on AirBus 320 (as USA will now allow captains through their air space > 65 (we now 69) - so senior captains have to either jump to right hand seat for younger less senior captains or convert back to A320 which don't fly to USA.

    The interesting point he made - as we are both mathematically and physics trained, and both did well in maths - and both continue to write high level computing code and learn newer high level languages - the captains who DO NOT have this skillset - have ALL failed to convert to the newer Airbus A320 as captains - interesting.

    I continue to challenge my brain to mathematicail exercises as I think it just wards off age related problems.

    I mentioned before but will mention again - in the 1970s - all astro calculations were done manually and for a 3 star fix worked out 10 -20 minutes prior - (but was easily undone as the P3B Orion was travelling at 360 kts - 6 nms/min so when you went to take the fix you were 120 nms further on and the weather often changed dramatically.

    And in the 70s technology was changing quickly - no such thing as PCs - but hand held calculators were advancing quickly - however, you lost everything whenenver you turned it off - (1977) TI-59/ HP-41CV/CX Programmable Personal Calculator with magnetic strips for storage.

    We used the RAF AP3270 Vol I, II, III for our astro calculations - so I inserted using appropriate spherical trig calculations - put all the 3270 info into magnetic strips - and to work out a 3 star fix - 1 min.

    The beauty of this method was I could work backwards - if we were in and out of cloud (not unusual) - as I knew the navigational stars and could easily identify most of the needed ones quickly - I could just shoot at approximately 120 deg separation - and then work backwards and come up with the fix information after the event.

    That was magic in the late 70s - magic.

    It was cumbersome as you had to leave the calculator on else the data vanished and you had to reread the data - and magnetic strips were not foolproof - they errored easily - so I always carried backups x 2.

    Then the HP 42S scientific came out - retined its memory even when powered off - I had left P3c by then and was flying a desk - I still have my HP42S and still use - it the beauty of the Hewlett Packard over TI was RPN - which is s omuch easier to use to solve complex mathematics even today - but no one teaches it anymore.

    So David your comment was interesting.

    Here is a picture of the HP 42S that came out in the late 80s and the HP 32S - a newer later version I gave to my son for his maths - he gave it back to me recently - way to complex he said -dad.

    I note in a post yesterday by Ed Popko - with a link to an Air Navigation LHA XI computer - niffty little computer - we never had those in the RNZAF - might have to try and get one if they are around.

    Sure computers nowadays make these things obsolete - but hey - when the battery or power goes on your electronic device - we are left dead in the water!

    Happy New Year Everyone

    PS - took my new Davis Mk 25 sextant - packed the family and went to the beach - 2.5 hrs drive away - East Coast - so by the time we arrived and it was a cracker day and the horizon perfect the sun was west of me - and no moon - and I left my false horizon at home.

    Oh well - the limits of the marine sextant - my A8A aero will arrive mid January.

    I did align and get a fell of the marine sextant - all new to me


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