NavList:

A navigation star list and a great star atlas
From: Frank Reed
Date: 2024 May 17, 08:49 -0700

In Maskelyne's "British Mariner's Guide" published in 1764 there are two lists of stars. One is a list of stars for shooting lunars, which has some quirks, and there is also a general list of 47 bright stars useful to navigators, comparable to the list of 57 in the modern Nautical Almanac. There have been many lists of navigation stars in the past three hundred years or so. This one deserves a little attention since the source is the (soon to be) Royal Astronomer. Rather than try to format it as plain text or upload a spreadsheet, which many of you might find problematic, I've made an image of the spreadsheet table I put together from the original. See below.

Some things I noticed:

• There is significant overlap between Maskelyne's 47 and the modern Nautical Almanac's 57 (see the MODERN ID and NAMOD columns in the table).
• Maskelyne includes more stars than necessary in, what must be, his favorite part of the sky, around Pegasus, Andromeda, and Perseus:
  ...he has Algenib, Mirach, Algol, and Scheat.
• Maskelyne continues the old practice of describing the stars in Ptolemaic fashion by telling us where to find it in a constellation:
  ...Rigil  Kentaurus (alpha Centauri) is listed as "the bright star in the eastern foot of the Centaur".
• Maskelyne's 1764 list, like the modern N.A. list, does not include Polaris.
• Poor Castor makes the cut, along with its twin, Pollux. We don't really need it, and Pollux is a better choice, but I have always felt bad for Castor...
• There are a couple of surprising additions:
  ...we get Zubeneschamali along with everybody's favorite faint nav star Zubenelgenubi, as well as Acrab nearby in Scorpius.
  ...the odd star out that originally caught my attention is the star now known as Phact, alpha Columbae, down to the lower right of Sirius.
• The list of recommended lunar stars is a bit different from the final list of nine that lasted for over a century. Maskelyne includes:
  ...Algenib, Menkar (alpha Ceti), Elnath, Kaus Australis, and one of the alphas in Capricornus.
• Several of the lunars stars are listed as "red", which is smart. This is useful identifying info --except that Regulus is counted "red" (it isn't!).

I have to imagine Maskelyne being a little embarrassed by his choice of alpha Capricorni. The coordinates don't seem to work, and it's a visual double star, so what was a lunarian supposed to measure?? A few years later, he dropped that choice and replaced it with poor little beta Capricorni (Dabih), which was the "tenth" lunar star officially tabulated in the Nautical Almanac along with the others for just a few years beginning in 1767. That one, too, was dropped quickly... So much for that darn dugong! Dugong? Sure, I like to see Capricornus, the "sea goat", as a dugong --close kin of a manatee, which may well have been a creature familiar to the inventors of that constellation in ancient Sumer or Babylon.

Anyone see any other curiosities in these star lists? By the way, the working of lunars before the Nautical Almanac was published was done in ecliptic coordinates, which is why the lunar stars were listed separately. I didn't copy in the ecliptic coordinates in the spreadsheet that my image is based on. Maybe another time...