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Air and Nautical thenauticalalmanac.com. This link has both Nautical and Air almanacs. The latter is the official version, the former is one they have computed as the others online are as well. Includes related cel nav resources... in fact, tons of resources.
We recommend that all 3rd party almanac data be confirmed with official USNO data before depending upon them. |
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Celestial Navigation Data online USNO SITE DOWN TILL END OF APRIL. Quite simply the celestial navigator's dream page. Enter time, date, and DR position and it prints out all data for all objects in the sky. Not only provides almanac data for each body above the horizon, but also includes Hc, Zn, and the altitude corrections so you could correct backwards to get actual Ha and Hs (add your own dip and IC).
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Download almanac Nicely done with a lot of background info. see the Compiled Manuals section at the end.
We recommend that all 3rd party almanac data be confirmed with official USNO data before depending upon them. |
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Equation of Time A nice write up with good illustrations on the Equation of time. |
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Nautical Almanac pages online From Omar Reis at Tecepe Nav, an online resource that prints near facsimile of Nautical Almanac daily pages. As with any source of data we might rely upon, we should always spot check a few points to see that all is well. This is true when we are using any re-computations or even reproductions of government data, even printed documents.
The Starpath Perpetual Almanac will also print almanac data to printer or text files, but we do not use the same page layout as the Nautical Almanac. |
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Online almanac Very compact, fast, and easy to use almanac data, also very nicely setup for printing. Since it is from a Lunar Distance website, we might presume the data are precise since the lunars would not work otherwise.
We recommend that all 3rd party almanac data be confirmed with official USNO data before depending upon them. |
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Interactive Star Maps There are many such sites online, here we present the best ones we have seen and ones we use ourselves. The principle source also has a complete package that can be downloaded to run offline. |
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Live view of sun spots When taking sextant sights of the sun we often see prominent sun spots -- they show up as black marks on the sun's disk, especially when using a higher power scope. Here is a place you can coordinate what you see in the sextant scope with what the astronomers are monitoring at this time, and then watch how they evolve with time. So far we have not tested this. Just found it (Mar 24,05) so if you have a chance to test this and compare sextant sights with this, please let us know in the cel nav general discussion group. |
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Make your own star charts Wonderful open source program that creates beautiful star charts to your design. |
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Positional Astronomy HQ Want to know how celestial bodies move across the sky and how the almanac is computed, then the name of what you want is "positional astronomy," and this is a wonderful starting point on that quest... in fact, everything is here in the various links they provide. A wonderful resource with many interesting applets and equations for about everything. |
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Stars and Constellations The personal site of an astronomy professor, is a wonderful starting point to learn all about individual stars and constellations. Select a star or constellation, learn all about it, then view one of several star maps of the region. Many links to astronomy related sites. If you like the stars, you can spend hours here following links around the sky. |
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Celestial Navigation Net Decorative, philosophical, and, most important, comprehensive. The webmistress of this site has done an excellent job in gathering together and keeping updated a massive number of related links, not to mention the extensive original content she has posted. It is easy to tell that she loves the subject and has studied it extensively.
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Tecepe Nav An outstanding amount of navigation accomplishments from Omar Reis in Brazil, a multi-talented navigator, sailor, engineer, software developer, artist. Includes numerous shareware products and online services including charting program, cel nav program, star id, online almanac, lessons in cel nav, and even how to build a sextant. His site and resources have been developing over the past 10 years or more. Very good links and tips on computer based navigation in general. |
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Typos and errors Cotter's work on the History of Nautical Astronomy is the standard reference on the subject, but numerous errors and typos have been found and compiled by George Huxtable and Jan Kalivoda, which are itemized here. A good list to have at hand when reading the book in depth. |
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Lunars All about lunar distance measurements, including history, present predictions, and even analysis online. We also have articles on lunars in the Library/In-depth Articles section, and we of course also reduce lunars in the starpilot programs (see software and accessories catalogs). |
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cel nav in the space program Not many realize that celestial navigation plays a key role in satellite and space navigation in general. Here is one story about the use of cel nav in the Apollo program. |
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Foundation for the Promotion of the Art of Navigation A most worthwhile non-profit organization that does just what its title says. Plus they offer good discounts to members on all US charts and navigation publications. One voyage worth would save much more than the $35 membership fee. Unique and interesting newsletter is included. The organization covers all aspects of navigation, but most of the content is on celestial navigation and this is indeed a resource for celestial information that is not available elsewhere. See membership information and newsletter archive
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Pub 229 If you have our CD version of the Cel Nav course, then you have these files on your CD already and would not have to download them. FURTHERMORE, the ones we provide are indexed and bookmarked so they are much easier to use. As a rule, however, the paper versions of these are more convenient, so if you plan to use them as your main source, then the paperback versions at about $20 per volume would be worth it. You could not print these for that amount from the files. But the computer files might serve as a backup, or could be useful for comparing solutions from one set of tables to the other... although we discuss this in the course in some detail.
Pub 229 are more precise than Pub 249, data are given to 0.1', but they are rather bulkier and more expensive since more volumes are needed. Also some users find them a bit more complex to use. |
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Pub 249 If you have our CD version of the Cel Nav course, then you have these files on your CD already and would not have to download them. FURTHERMORE, the ones we provide are indexed and bookmarked so they are much easier to use. As a rule, however, the paper versions of these are more convenient, so if you plan to use them as your main source, then the paperback versions at about $20 per volume would be worth it. You could not print these for that amount from the files. But the computer files might serve as a backup, or could be useful for comparing solutions from one set of tables to the other... although we discuss this in the course in some detail.
The exception to this, is Pub 249, Vol 1 on selected Stars. You could download this one and just print the lat ranges you care about and use it for choosing star sights. |
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Correct time now A quick look at GMT as of the time you click the link, includes other standard US time zones as well. Plus a link that keeps the time ticking and displayed on the screen. |
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GMT HQ All you ever wanted to know about time... and more. Plus ways to have your computer reset to correct zone time of your choice with a keystroke (see Freeware and Shareware resources).
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Radio sources of GMT (UT) A good discussion of UTC sources. See also the article in the Library/Articles section on the distinctions between GMT, UTC. |
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