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!

A big thank you in advance.

Cheers,

John Nagelson

"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!

A big thank you in advance.


Dunno where you can find them online but the 57 stars a

Acamar
Achernar
Acrux
Adhara
Al Na'ir
Aldebaran
Alioth
Alkaid
Alnilam
Alphard
Alphecca
Alpheratz
Altair
Ankaa
Antares
Arcturus
Atria
Aviar
Bellatrix
Betelgeuse
Canopus
Capella
Deneb
Denebola
Diphda
Dubhe
Elnath
Eltanin
Enif
Fomalhaut
Gacrux
Gienah
Hadar
Hamal
Kaus Aust
Kochab
Markab
Menkar
Menkent
Miaplacidus
Mirfak
Nunki
Peacock
Pollux
Procyon
Rasalhague
Regulus
Rigel
Rigel Kent.
Sabik
Schedar
Shaula
Sirius
Spica
Suhail
Vega
Zuben'ubi

and to make it 58 add Polaris which is seen as a special case.

Eugene L Griessel

Sex is not the answer. Sex is the question. 'Yes' is the answer.

More importantly - can anyone list a website that explains:

1. how \ where to find those 57 stars and
2. how to use them for navigation

I was only aware of polaris, the southern cross and orion's belt as
navigational stars.

"Jim" wrote:

More importantly - can anyone list a website that explains:

1. how \ where to find those 57 stars and
2. how to use them for navigation

I was only aware of polaris, the southern cross and orion's belt as
navigational stars.

Astro Navigators would be pretty stuck with only those stars to guide
them. You need a minimum of 3 stars, preferably widely spaced to get
good angles of cut for a halfway decent position.

Polaris can give you a pretty fair latitude on its own but not a
longitude. And only in the Northern hemisphere. The Crux can give
you a fair idea of where South is but only in the southern hemisphere.

Eugene L Griessel

Plan to be spontaneous tomorrow.

On Apr 4, 7:57 am, "Jim" wrote:
More importantly - can anyone list a website that explains:

1. how \ where to find those 57 stars and
2. how to use them for navigation

I was only aware of polaris, the southern cross and orion's belt as
navigational stars.

When I was flying KC-135's in the '70's we used celestial navigation
on overwater flights.

IIRC you should be able to find the lists in either the Air Almanac
(most likely) or the H.O. 249 sight reduction tables. Probably doesn't
help the nautical guys any but I don't have any experience in that
area.

The ideal solution is to get a three-star fix. Each star shot gives
you a single line of position (LOP) and a three-star fix (using stars
spaced correctly in the sky) would give you three LOP's, and when
plotted on a chart would form a small triangle. Your position should
be somewhere inside that triangle, so the smaller the triangle the
better.

That, combined with your DR position you plotted from your last fix
using best-known winds will give you a pretty accurate position.

In the daytime, where only the sun (and maybe the moon) could be seen
you would usually get only a single line of position. On an east-west
flight that LOP would be a speed line in the morning/evening and a
course line in the middle of the day. On a typical 6-8 hour flight
from, say, Hickam AFB in Hawaii to Anderson AFB in Guam you'd get both
over the course of a flight.

Sometimes in the daytime you could see Venus through the sextant (we
used a periscopic bubble sextant) but it could be a challenge.

--Walt
Bozeman

"Walt" wrote:

On Apr 4, 7:57 am, "Jim" wrote:
More importantly - can anyone list a website that explains:

1. how \ where to find those 57 stars and
2. how to use them for navigation

I was only aware of polaris, the southern cross and orion's belt as
navigational stars.

When I was flying KC-135's in the '70's we used celestial navigation
on overwater flights.

IIRC you should be able to find the lists in either the Air Almanac
(most likely) or the H.O. 249 sight reduction tables. Probably doesn't
help the nautical guys any but I don't have any experience in that
area.

The ideal solution is to get a three-star fix. Each star shot gives
you a single line of position (LOP) and a three-star fix (using stars
spaced correctly in the sky) would give you three LOP's, and when
plotted on a chart would form a small triangle. Your position should
be somewhere inside that triangle, so the smaller the triangle the
better.

That, combined with your DR position you plotted from your last fix
using best-known winds will give you a pretty accurate position.

In the daytime, where only the sun (and maybe the moon) could be seen
you would usually get only a single line of position. On an east-west
flight that LOP would be a speed line in the morning/evening and a
course line in the middle of the day. On a typical 6-8 hour flight
from, say, Hickam AFB in Hawaii to Anderson AFB in Guam you'd get both
over the course of a flight.

Sometimes in the daytime you could see Venus through the sextant (we
used a periscopic bubble sextant) but it could be a challenge.

And doing it in a fast aircraft one is really bedevilled by factors
that us sailors thankfully don't suffer. Like the coriolus effect on
the bubble in the sextant and postion lines many miles apart that have
to be transferred with drift guessed at etc.
At sea, given the right conditions, a bit of luck and lots of skill
one could plot a position within half a mile. I hate to think what
sort of error air navigators had! As they said in World War two -
celestial navigation is best left to the birds! That's why electronic
navigation aids were such a priority.

Eugene L Griessel

The basic delusion that men may be governed and yet be free.

On Apr 4, 8:57 am, "Jim" wrote:
More importantly - can anyone list a website that explains:

1. how \ where to find those 57 stars and
2. how to use them for navigation

I was only aware of polaris, the southern cross and orion's belt as
navigational stars.

Get a copy of Bowditch
The American Practical Navigator.

Joe

"Jim" wrote:

More importantly - can anyone list a website that explains:

1. how \ where to find those 57 stars and

Finding the stars comes from knowledge of the heavens. It's not
difficult to learn the minimum amount needed to identify 5 or 6 bright
stars in any heaven that would be above you. You could also use a
planisphere or with sight reduction tables you could work out more or
less where the star would be at the time you want to use it for
navigation. You look in that direction at that altitude and then the
brightest one in that area is likely to be your navigation star.

2. how to use them for navigation

All celestial navigation is based on a very simple theory. At any
given moment (exact time) every star in the heavens above has a
zenithal point somewhere on earth. That is a point where it is 90
degrees to the earth below. Directly overhead. At that exact moment
you measure the angle between your position and the star. Then you
can use a giant imaginery compass, with one point stuck into that
zenithal point and with the two legs set at the angle you measured, to
inscribe a giant circle on the earth. Somewhere on this circle you
must be. Do this with three stars and those three imaginary circles
will intersect at a single point. That's where you are on the globe.

That's the theory. In practice it is a little more complicated. As
others have indicated there are very good online and paper resources
which will explain the details.

It is also fairly pricey to do it this way - a good sextant and
reliable chronometer will set you back a bit but they are one time
expenditures. Annually you will have to purchase celestial tables -
and they can be very pricey.

But this is the purist celestial navigator's way. I have a cousin who
during the eighties did a few years delivering yachts around the
world. He had a scanty knowledge of navigation. By using a few
tricks - like a good celestial navigation calculator - and a cheap
plastic sextant he avoided running into anything expensive. Most
navigation is pretty commonsensical - give a clot the most expensive
GPS and he will still run into things, probably while peering at the
GPS, while an expert navigator can make do with very little. I had a
pal who once sailed from Cape Town to St Helena using a cheap
transistor radio for the time and an old war surplus box sextant.
Even those aids were pretty pointless as for the first week he was in
fog and couldn't see a star or the sun. And he made it spot on. He
had been a navigator on an ocean minesweeper during WW2 - and their
navigation had to be pretty good and accurate. His skill made up for
the lack of fancy equipment.

Eugene L Griessel

The basic delusion that men may be governed and yet be free.

Try http://www.nga.mil/portal/site/maritime/
Select "publications" then from the drop down list you can choose
digital sight reduction tables, either air or marine. That may help.

On Apr 4, 5:34 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.

Index of Selected Stars - (West to East)
http://www.angelfire.com/nt/navtrig/F1.html

couldn't find the 173


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!

A big thank you in advance.

Cheers,

John Nagelson