On Apr 4, 5:11 pm, " wrote:
On Apr 4, 2:34 am, "John Nagelson" 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???

Cheers,

John

"John Nagelson" wrote:

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???

Any visible star can be used for navigation. The 57 given in
Alamanacs are all bright stars which are not easily confused with
others. The majority of the 173 you will find are sometimes pretty
iffy and any celestial navigator would probaly only resort to them in
fairly awkward circumstances. When you start hitting 3 magnitude and
higher it gets more awkward to distinguish the star one wants from the
background - especially on a ship which may be moving quite heavily.
Brown, for instance, (In the last copy I bought) gives some stars up
to 4 magnitude. But practically, unless you are that rarest of
navigators who can distinguish 173 stars with certainty, anything much
higher than 2 magnitude becomes chancy. Wheras the SHA and Dec of the
57 principal stars are given on the daily pages of nautical almanacs I
don't think I have ever seen the lesser stars listed thus. They are
usually confined to a couple of pages in the back giving the SHA and
Dec for the month only. In principle, unless you plan to sail the
world, you could probably get away with an intimate knowledge of about
sixteen stars in your hemisphere.




Eugene L Griessel

For every person willing to teach, there are 30 not willing to be
taught

On Apr 5, 1:48 pm, "John Nagelson" wrote:
On Apr 4, 5:11 pm, " wrote:



On Apr 4, 2:34 am, "John Nagelson" 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

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

http://www.nga.mil/portal/site/nga01/

http://www.celestialnavigation.net/

http://websurf.nao.rl.ac.uk/

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.

John

http://www.nga.mil/portal/site/nga01/

http://www.celestialnavigation.net/

http://websurf.nao.rl.ac.uk/

"John Nagelson" wrote:

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

I'm sure your life must be empty not knowing that the likes of Eta
Virginis, Delta Velorum and Beta Corvi and the like are also on rare
occasions used to navigate by. I could give the full list but really
think its pointless.

Eugene L Griessel

We do precision guesswork.

On Apr 6, 5:26 pm, (Eugene Griessel) wrote:
"JohnNagelson" wrote:
Already downloaded this and printed it - very nice chart
but shows the 57 with names and numbers, not the 173.

I'm sure your life must be empty not knowing that the likes of Eta
Virginis, Delta Velorum and Beta Corvi and the like are also on rare
occasions used to navigate by. I could give the full list but really
think its pointless.

Hi Eugene, you only had to ask and I would have said why I want
them :-)

I am a comparative anthropologist studying the history of maritime
star lore
in various parts of the world, including the west. This is such a wide-
ranging
subject, geographically and chronologically, that I am ruthlessly
restricting
the number of stars under consideration at the outset. Various
interesting stars
are outside of the 57, e.g. Algol (Beta Persei), and Mizar.
I wouldn't be at all surprised if I find material on the stars that
you
mention. Certainly the first and third look likely candidates, also
known
as Zaniah and Kraz.

If you could post the full list it would not fill up an empty life,
but it would be much appreciated.

John

* John Nagelson wrote, On 4/6/2007 12:32 PM:
On Apr 6, 5:26 pm, (Eugene Griessel) wrote:
"JohnNagelson" wrote:
Already downloaded this and printed it - very nice chart
but shows the 57 with names and numbers, not the 173.
I'm sure your life must be empty not knowing that the likes of Eta
Virginis, Delta Velorum and Beta Corvi and the like are also on rare
occasions used to navigate by. I could give the full list but really
think its pointless.

Hi Eugene, you only had to ask and I would have said why I want
them :-)

I am a comparative anthropologist studying the history of maritime
star lore
in various parts of the world, including the west. This is such a wide-
ranging
subject, geographically and chronologically, that I am ruthlessly
restricting
the number of stars under consideration at the outset. Various
interesting stars
are outside of the 57, e.g. Algol (Beta Persei), and Mizar.

Algol? Although relatively bright, Algol was omitted from the 57, I
believe because it is a variable star. In fact, it was recognized by
the ancients as variable, and known as the "Demon Star." (Algol and
Ghoul come from the same root.)

I have an affinity for the star because my first experience working in
astronomy was being on the team that discovered Algol was a strong
emitter of X-Rays.

On Apr 6, 11:26 am, (Eugene Griessel) wrote:
"John Nagelson" wrote:
Already downloaded this and printed it - very nice chart
but shows the 57 with names and numbers, not the 173.

I'm sure your life must be empty not knowing that the likes of Eta
Virginis, Delta Velorum and Beta Corvi and the like are also on rare
occasions used to navigate by. I could give the full list but really
think its pointless.

Eugene L Griessel

We do precision guesswork.

173 sounds like too much information - I mean how many are needed to
sucessfully navigae with? Do you really need the 173? Do you need the
57 in total to navigate?

"Jim" wrote:

On Apr 6, 11:26 am, (Eugene Griessel) wrote:
"John Nagelson" wrote:
Already downloaded this and printed it - very nice chart
but shows the 57 with names and numbers, not the 173.

I'm sure your life must be empty not knowing that the likes of Eta
Virginis, Delta Velorum and Beta Corvi and the like are also on rare
occasions used to navigate by. I could give the full list but really
think its pointless.

Eugene L Griessel

We do precision guesswork.

173 sounds like too much information - I mean how many are needed to
sucessfully navigae with? Do you really need the 173? Do you need the
57 in total to navigate?

When one navigates by the stars, using a normal marine sextant, the
only time one can shoot the stars is during twilight as both the
horizon and the stars must be visible. So morning and evening
twilight are the only times (barring on odd occasions when the moon is
bright enough to see the horizon). Thus the stars need to be bright.
I doubt many celestial navigators, that is the marine kind, have ever
used all 57 the almanac routinely lists on the daily pages. One needs
three bright stars to get a position. If one is neurotic (like me)
you shoot an extra one or two just to make sure that the position has
not been bedevilled by bad time, bad measurement, bad calculation etc.
My method is to see which bright stars will be visible during twilight
from my ded reckoning postion (using the almanac) - choosing the
brightest and which will give me good angles of cut and figuring out
their estimated azimuth and elevation. So before I even get the
sextant out I know which directions and elevations I will be looking
in. Usually the only bright star there will be the one I want to use.

Chuck in the odd planet, the moon if it obliges well, and I'm away.

I've always maintained that learning how to find about 16 stars in the
hemisphere you are in will do you admirably. I mean I can look up and
identify (say) Castor and Pollux, Betelgeuse, Rigel, Procyon, Sirius,
Capella, Aldebaran, Saiph, Rigel Kentaurus, Alpha Crux, Acnernar,
Canopus and Fomalhaut with 100% certainty. What more do I need -
unless things are really badly overcast - and then celestial becomes
truly iffy anyway. Either the horizon or the star you want will be
obscured. I remember taking a nothern hemisphere aviator on his first
night in the south to show him the crux and being so bedevilled that
no more than two stars of it or the pointers were ever visible at one
time. Big disappointment for him! Next night he saw them all.

BTW - I think the Flamsteed numbers only go as high as 137 - not 173.
May be wrong, should check,

Eugene L Griessel

A free society is one where it is safe to be unpopular.

Eugene Griessel wrote:
BTW - I think the Flamsteed numbers only go as high as 137 - not 173.
May be wrong, should check,

Taurus has the most stars with Flamsteed numbers; the easternmost is
labelled 139 Tauri, I think. But that's per constellation--it shouldn't
have any bearing (!) on how many stars there are in an all-sky
catalogue.

--
Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html