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list of 173 'navigational' stars?
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 |
list of 173 'navigational' stars?
"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. |
list of 173 'navigational' stars?
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. |
list of 173 'navigational' stars?
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. |
list of 173 'navigational' stars?
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 |
list of 173 '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. |
list of 173 'navigational' stars?
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/ |
list of 173 'navigational' stars?
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 |
list of 173 'navigational' stars?
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 |
list of 173 'navigational' stars?
"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. |
list of 173 'navigational' stars?
On Apr 4, 2:57 pm, Sam Wormley wrote:
wrote: 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 Or read it athttp://www.irbs.com/bowditch/ For a student working on a class project I agree. For a sailor it's not the same, any sailor worth his salt has a copy of bowditch aboard. Joe |
list of 173 'navigational' stars?
wrote in message oups.com... On Apr 4, 2:57 pm, Sam Wormley wrote: wrote: 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 Or read it athttp://www.irbs.com/bowditch/ For a student working on a class project I agree. For a sailor it's not the same, any sailor worth his salt has a copy of bowditch aboard. Joe Even if they don't carry, or know how to use, a sextant. Right? ;-) |
list of 173 'navigational' stars?
On Wed, 4 Apr 2007 18:15:34 -0500, "KLC Lewis"
wrote: Even if they don't carry, or know how to use, a sextant. Right? ;-) There's a lot in there other than celestial. |
list of 173 'navigational' stars?
On Apr 4, 6:54 pm, Wayne.B wrote:
On Wed, 4 Apr 2007 18:15:34 -0500, "KLC Lewis" wrote: Even if they don't carry, or know how to use, a sextant. Right? ;-) There's a lot in there other than celestial. Indeed Wayne, it's one of my treasured items passed down in the family. And if you want to learn celestial, you will not find a better publication. As I said, and KLC shows, any sailor worth his salt has a copy of bowditch aboard. Joe |
list of 173 'navigational' stars?
wrote in message oups.com... On Apr 4, 6:54 pm, Wayne.B wrote: On Wed, 4 Apr 2007 18:15:34 -0500, "KLC Lewis" wrote: Even if they don't carry, or know how to use, a sextant. Right? ;-) There's a lot in there other than celestial. Indeed Wayne, it's one of my treasured items passed down in the family. And if you want to learn celestial, you will not find a better publication. As I said, and KLC shows, any sailor worth his salt has a copy of bowditch aboard. Joe Ain't much salt in the Great Lakes. But I also didn't say that I didn't have a copy, did I? Cute dig, though. |
list of 173 'navigational' stars?
|
list of 173 'navigational' stars?
On Apr 4, 8:12 pm, "KLC Lewis" wrote:
wrote in message oups.com... On Apr 4, 6:54 pm, Wayne.B wrote: On Wed, 4 Apr 2007 18:15:34 -0500, "KLC Lewis" wrote: Even if they don't carry, or know how to use, a sextant. Right? ;-) There's a lot in there other than celestial. Indeed Wayne, it's one of my treasured items passed down in the family. And if you want to learn celestial, you will not find a better publication. As I said, and KLC shows, any sailor worth his salt has a copy of bowditch aboard. Joe Ain't much salt in the Great Lakes. Not much sailing either since you are frozen in half the year...sorry to hear it. But the saying " Worth his salt" refers to the amount of salt in your body, not the amount of salt in your local lake. But I also didn't say that I didn't have a copy, did I? If you did have a copy... you would have known of all the other great subjects Bowditch covers besides celestial navigation. Unless you never read it, you would see it value beyond using a sextant. Joe Cute dig, though.- Hide quoted text - - Show quoted text - |
list of 173 'navigational' stars?
"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. |
list of 173 'navigational' stars?
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 |
list of 173 'navigational' stars?
"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 |
list of 173 'navigational' stars?
But the saying " Worth his salt" refers to the amount of salt in your body, not the amount of salt in your local lake. That's incorrect. It refers to whether you are worth being paid, your salt being your salary in the Roman legion. Of course, if you're an old salt, that's another matter. :) |
list of 173 'navigational' stars?
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/ |
list of 173 'navigational' stars?
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/ |
list of 173 'navigational' stars?
"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. |
list of 173 'navigational' stars?
"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. Eugene L Griessel We do precision guesswork. |
list of 173 'navigational' stars?
|
list of 173 'navigational' stars?
On Apr 6, 9:38 am, "John Nagelson" wrote:
On Apr 6, 6:19 pm, (Eugene Griessel) wrote: "JohnNagelson" 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. Eugene L Griessel Thank you very much, Eugene. (I hadn't read the above post before I replied to your other one). Unfortunately even this doesn't work, though!! I downloaded and searched for '150', '159', and '171' (chosen at random), and nothing came up - so some of the 173 must be missing. Aarghh! And some of the numbers appear multiple times, like 44. There doesn't appear to be any online list of the 173. Given that Bowditch is online (several places) I'm surprised the Nautical Almanac is not. Since the list is readily available in the Almanac, buy the almanac from the USGPO. |
list of 173 'navigational' stars?
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". It indicates which stars in the table ARE navigational stars by giving their number. All 57 of them are there with their average SHA and Dec for each of the 12 months of the year. These particular stars were chosen as "navigational stars" based on their brightness and the fact that their distribution on the celestial sphere made them useful for establishing one's position. That's why you'll find them listed on every one of the daily pages in the almanac. These are the ones that navigators will normally use to determine their position at sea - or in the air. 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). If a navigator was to bring down a star, in all likelihood it would be in this range and thus in this table. When might one be called on to use the other 116 stars? Well, at sea the sky is not always cloudless. If, through a break in the clouds you find a star that would be great for getting a fix, you bring it down and record the time of observation and the star's sextant altitude. At this point, you then have the task of figuring out which star it was so that, with it's SHA and Dec, you can determine the corresponding LOP. This is how you do that: You work out your corrected altitude for the star and then determine your DR position at the time of the sight. With this information, you can then use a sight reduction table (or your calculator/computer program) to determine the "calculated/estimated" SHA and Dec of that star. Entering the Stars table, you can, with the calculated SHA, narrow down the list of possible candidates for the star sighted and, with the calculated Dec, determine the actual star that was brought down. If it was one of the navigational stars, you go back to your daily page and perform the usual ritual. If not, you simply extract the SHA and Dec listed in the table for the actual star that you brought down and go from there. Now you know what that table is all about. Lots of luck with your project. ron |
list of 173 'navigational' stars?
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. John |
list of 173 'navigational' stars?
"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 |
list of 173 'navigational' stars?
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list of 173 'navigational' stars?
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 |
list of 173 'navigational' stars?
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list of 173 'navigational' stars?
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list of 173 'navigational' stars?
"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. |
list of 173 'navigational' stars?
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 |
list of 173 'navigational' stars?
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 |
list of 173 'navigational' stars?
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list of 173 'navigational' stars?
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 |
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