Sight Reduction Tables For Air Navigation Pub. No. 249 Vol. 1 Eopch 2020

Printed well. Gives good star sight recommendations. Good through 2024. Soft cover. I use it in conjunction with Nautical Almanac. It would be wise to have both on hand.

Excellent data source for Celestial Navigation. Easy to read.

If you are looking for the reduction tables for sextant navigation on a sailboat and it is still before 2025, this is the book you want.

Exactly what was needed for celestial sight planning.

I've been doing practice sight reductions with these tables. Taking reasonable care, I can do the paperwork part of a three star fix in about 30 minutes, from planning the sights to the final position fix, using a universal plotting sheet - and I'm not very fast. For any combination of latitude and local hour angle of the first point of Aries, publication 249 volume 1 gives the heights and azimuths for 7 stars and indicates the three best stars to use for sextant sightings - anywhere on earth.For paperwork practice, I simulate the sextant sightings using a phone app. So far, I've found accuracy to be within a nautical mile or two in these simulated cases, eyeballing the centre of the cocked hat and correcting for the year using the simple table in the front of the book. The centre of the cocked hat is not the true position, of course, (there's only about a 25% chance the true position is inside the cocked hat), but unless you're within, say, 10 miles of land, this is good enough for practical navigation. If you're close to land and under way, you're looking out the window, not doing celestial navigation!If I use the Publication 229 tables I get better accuracy, as the computed object heights are tabulated to the nearest tenth of a minute, so my simulated sightings produce a very small cocked hat. The Publication 229 tables are a bit more work to use, though, and the six volumes are a bit heavy for my little yacht. I've only bought two of the six volumes, covering 15° to 45° latitude, all of Australia except the northernmost 4° of latitude where it's too warm for us Tasmanians. For Tasmania I need only to carry one volume. My sextant sightings are not guaranteed to be accurate to a tenth of a minute, though, so the extra work in using Publication 229 probably won't improve my fixes enough to be worth the time and effort.