Next message: Richard Thomas: "Re: RYA Ocean Theory"
Alex E wrote:
"In many places I see an article of Maskelyne
on Hadley octant mentioned, as
"a supplement to 1774 almanac".
Even the later almanacs mention this.
I downloaded the whole 1774 almanac and I
do not see any supplements in it.
Where could they be??"
On the site, you will find THREE scans of a Nautical Almanac for 1774. One
has 161 pages. The others have 230 and 252 pages. Take a wild guess which one
does NOT have the appendix you're looking for.
Here are my notes on the appendices from that year:
appendix on the elements of the lunar tables.
appendix on Hadley's quadrant: adjusting for back-observation, telescope
collimation, swinging the arc, shade error, proper sizing of mirrors.
appendix by Lyons on positioning a meridianal telescope.
appendix by Lyons on using the "general tables of refraction and parallax"
(Shepherd's Cambridge Tables) for clearing lunars.
A number of the other almanacs appear in several versions. Some of these are
actually second editions, labeled that way on the title page. Generally, I
picked the one with the greater number of pages.
-FER
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
