Astro Navigation

Thank you all once again!

Quite correct Peter NP303/AP3270 are the Janet and John/Ladybird rapid sight reduction version for current use.

Prior to that AP1618 ruled – varous volumes Lat 0 to 89 in 4 degree incremental volumes. (observer assumed at 5,000 ft)

Air Almanac AP1602 also required!

22 stars normal but 35 stars for Sun, Moon and planets for internal degrees of declination 0 to 28 degrees.

Regards
Ross

Blimey, only 7 stars, we had to learn about 30 and didn’t have pretty books like that. I remember fumbling about with 2 clunky cloth bound volumes. We needed a semi house trained killick to translate for us:D:D

Rumour had it that the Admiralty designed the three volumes to suit the mental ability of the RAF Navs

i.e. full title was too much to remember but “use the red one then the yellow one” was just right for their ability.

These are the current AP3279/NP303

Red One – Volume 1 – Selected star epochs

Green One – Volume 2 – 0 to 40 degrees Lat, Declination 0 to 29 deg

Yellow One – Volume 3 – 40 to 89 degrees Lat, Declination 0 to 29 deg.

Essentially the marine publications are the same as the air ones just the bias of horizon that alters.

Aircraft ones are + or – x ft about 30,000 ft above horizon for the observers eye level, naval ones are sea level to about mast height <200ft.

Regards
Ross

http://astro.ukho.gov.uk/nao/news/ap3270/

Ross – Many thanks for that, what was the difference between the two volumes and their red/yellow cover identity please?

Colour of cover banding.

See Pomgo’s post #9
http://forum.keypublishing.com/showthread.php?96171-Sight-Reduction-Tables

Piccy of red tables
http://img.zvab.com/member/79098k/37905198.jpg

Regards
Ross