"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 7, 4:19 am, Ronald Wong wrote:

In article .com,
"John Nagelson" wrote:

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

Actually, the table that you found in the back of the Nautical Almanac
is NOT a table of the 173 "navigational stars".
So what's with all the other stars listed in a table in the back of the
almanac called "Stars" (note that the title of the table is NOT
"Navigational Stars")?

What is listed in the Stars table is all the stars down to a magnitude
of 3.0 (and a few that are even dimmer).

Many thanks Ron!

I got a list of the 173 brightest from:

http://www.atlasoftheuniverse.com/stars.html:

They are mostly under common names, but at least some of those that
aren't,
have got common names, e.g. Theta Aurigae is Bogardus, and Upsilon
Carinae
is Vathorz Prior.

====================

1. Sirius
2. Canopus
3. Rigil Kentaurus
4. Arcturus
5. Vega
6. Capella
7. Rigel
8. Procyon
9. Achernar
10. Betelgeuse
11. Hadar
12. Altair
13. Acrux
14. Aldebaran
15. Antares
16. Spica
17. Pollux
18. Fomalhaut
19. Deneb
20. Mimosa
21. Regulus
22. Adhara
23. Castor
24. Shaula
25. Gacrux
26. Bellatrix
27. Elnath
28. Miaplacidus
29. Alnilam
30. Alnair
31. Alnitak
32. Alioth
33. Mirfak
34. Dubhe
35. Regor
36. Wezen
37. Kaus Australis
38. Alkaid
39. Sargas
40. Avior
41. Menkalinan
42. Atria
43. Alhena
44. Peacock
45. Koo She
46. Mirzam
47. Alphard
48. Polaris
49. Algieba
50. Hamal
51. Diphda
52. Nunki
53. Menkent
54. Alpheratz
55. Mirach
56. Saiph
57. Kochab
58. Al Dhanab
59. Rasalhague
60. Algol
61. Almach
62. Denebola
63. Cih
64. Muhlifain
65. Naos
66. Aspidiske
67. Alphecca
68. Suhail
69. Mizar
70. Sadr
71. Schedar
72. Eltanin
73. Mintaka
74. Caph
75. Epsilon Centauri
76. Dschubba
77. Wei
78. Men
79. Eta Centauri
80. Merak
81. Izar
82. Enif
83. Girtab
84. Ankaa
85. Phecda
86. Sabik
87. Scheat
88. Aludra
89. Alderamin
90. Markeb
91. Gienah
92. Markab
93. Menkar
94. Han
95. Al Nair al Kent.
96. Zosma
97. Graffias
98. Arneb
99. Delta Centauri
100. Gienah Ghurab
101. Ascella
102. Zubeneschamali
103. Unukalhai
104. Sheratan
105. Zubenelgenubi
106. Phact
107. Theta Aurigae
108. Kraz
109. Ruchbah
110. Muphrid
111. Ke Kouan
112. Hassaleh
113. Mu Velorum
114. Alpha Muscae
115. Lesath
116. Pi Puppis
117. Kaus Meridionalis
118. Tarazed
119. Yed Prior
120. Aldhibain
121. Theta Carinae
122. Porrima
123. Hatysa
124. Iota Centauri
125. Cebalrai
126. Kursa
127. Kornephoros
128. Delta Crucis
129. Rastaban
130. Cor Caroli
131. Gamma Lupi
132. Nihal
133. Rutilicus
134. Beta Hydri
135. Tau Scorpii
136. Kaus Borealis
137. Algenib
138. Turais
139. Beta Trianguli Australis
140. Zeta Persei
141. Beta Arae
142. Choo
143. Alcyone
144. Vindemiatrix
145. Deneb Algedi
146. Head of Hydrus
147. Delta Cygni
148. Tejat
149. Gamma Trianguli Australis
150. Alpha Tucanae
151. Acamar
152. Albaldah
153. Gomeisa
154. Pi Scorpii
155. Epsilon Persei
156. Alniyat
157. Albireo
158. Sadalsuud
159. Gamma Persei
160. Upsilon Carinae
161. Matar
162. Tau Puppis
163. Algorel
164. Sadalmelik
165. Zaurak
166. Alheka
167. Ras Elased Australis
168. Alnasl
169. Gamma Hydrae
170. Iota Scorpii
171. Deneb el Okab
172. Beta Trianguli
173. Psi Ursae Majoris

====================

From what you say, a few of the above don't make it to the Nautical
Almanac list,
and a few that aren't above do!

Looking forward to delivery of my copy of the NA from Amazon :-)

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

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

On Apr 9, 4:10 pm, (Eugene Griessel) wrote:
"Jim" wrote:
On Apr 6, 11:26 am, (Eugene Griessel) wrote:
"John Nagelson" wrote:

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.

One needs three bright stars to get a position.

Interesting - makes me think of the definition of sunrise and sunset
in the Jewish religion: night begins when three stars are visible.

John

(Brian Tung) wrote:

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.

It is my understanding that the original Flamsteed numbers are the
ones used as the "navigational" stars? The brightest. May be
wrong....


Eugene L Griessel

I feel like I'm diagonally parked in a parallel universe.

Eugene Griessel wrote:
It is my understanding that the original Flamsteed numbers are the
ones used as the "navigational" stars? The brightest. May be
wrong....

I doubt it. The Flamsteed numbering extends to stars of about the fifth
magnitude (though there's a bit of inconsistency about this). Also, the
numbering is repeated per constellation. All told, there are something
more than 2,500 Flamsteed numbered stars.

--
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