"John Nagelson" wrote:

On Apr 6, 6:19 pm, (Eugene Griessel) wrote:
"John Nagelson" wrote:
On Apr 6, 2:52 am, " wrote:
On Apr 5, 1:48 pm, "JohnNagelson" wrote:

On Apr 4, 5:11 pm, " wrote:

On Apr 4, 2:34 am, "JohnNagelson" wrote:

Hello, the US Nautical Almanac lists 173 "navigational stars", of
which a shorter list of 57 is sometimes extracted.

I've been unable to find these lists online, although I have found
databases referencing many millions of stars!

Could someone tell me if they know where the lists of 57 and 173 stars
exists online.

Or if it doesn't, and someone has got the two lists in text format,
I'd be very grateful if they could post them in follow-up to this
message!

Bowditch's THE AMERICAN PRACTICAL NAVIGATOR in hardcopy, or
online in PDF form at URL:

http://www.irbs.com/bowditch/

A big thank you to everyone who has posted in reply. Bowditch looks a
fantastic
source on celestial navigation, which I will study.

Unless I am mistaken, though, it gives the list of 57 plus Polaris,
not the 173, although it says the latter is given in the US Nautical
Almanac.

Maybe there is a shareware navigation program somewhere that I can
pick out the
info from???

The Nautical Almanac is not available online or in PDF form, but
there's a free (shareware) program with the data that can be printed.

Check these out:

http://www.tecepe.com.br/scripts/AlmanacPagesISAPI.isa
http://www.tecepe.com.br/nav/download.htm
http://www.tecepe.com.br/nav/TheOnlineNauticalAlmanac.htm

Only uses 60 stars unfortunately!

http://aa.usno.navy.mil/data/docs/Nav_Star_Chart.html
http://aa.usno.navy.mil/data/docs/navstarchart.pdf

Already downloaded this and printed it - very nice chart
but shows the 57 with names and numbers, not the 173.

http://asa.usno.navy.mil/SecH/brightstars.html

Download the PDF file for one of the years. In it the names of some
stars are preceeded by a number - 1 to 173 will give you the stars you
want.

Does the ordering in the Nautical Almanac have a name?
I mean with Sirius at no.18, etc.
And could someone please enlighten me on the origin of the numbering.

Many thanks.

Look up the life of John Flamsteed, Astronomer Royal.

Eugene L Griessel

It is vain to say human beings ought to be satisfied with tranquillity:
they must have action; and they will make it if they cannot find it.
Jacob Bronowski

On Apr 9, 7:30 am, (Eugene Griessel) wrote:
"John Nagelson" wrote:

Does the ordering in the Nautical Almanac have a name?
I mean with Sirius at no.18, etc.
And could someone please enlighten me on the origin of the numbering.

Many thanks.

Look up the life of John Flamsteed, Astronomer Royal.

If I might answer my own question (!)...
The Nautical Almanac numbers the 57 navigational stars
simply in decreasing order of SHA.

Thus number 1 is Alpheratz, SHA 358 deg
number 2 is Ankaa, SHA 354 deg...
number 18 is Sirius, SHA 259 deg...
number 57 is Markab, SHA 14 deg

I should have spotted this!

Flamsteed numbered stars within each constellation,
in increasing order of RA, e.g. Sirius is 9 Canis Majoris.
With some the Flamsteed numbering is now out of sync though.

No such problem with the 57.
I wonder what system was used for numbering the others that make
up the Nautical Almanac 173.

John

On Apr 9, 7:30 am, (Eugene Griessel) wrote:
"John Nagelson" wrote:

Does the ordering in the Nautical Almanac have a name?
I mean with Sirius at no.18, etc.
And could someone please enlighten me on the origin of the numbering.

Many thanks.

Look up the life of John Flamsteed, Astronomer Royal.

If I might answer my own question (!)...
The Nautical Almanac numbers the 57 navigational stars
simply in decreasing order of SHA.

Thus number 1 is Alpheratz, SHA 358 deg
number 2 is Ankaa, SHA 354 deg...
number 18 is Sirius, SHA 259 deg...
number 57 is Markab, SHA 14 deg

I should have spotted this!

Flamsteed numbered stars within each constellation,
in increasing order of RA, e.g. Sirius is 9 Canis Majoris.
With some the Flamsteed numbering is now out of sync though.

No such problem with the 57.
I wonder what system was used for numbering the others that make
up the 173.

John