A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2016 Feb 27, 21:08 -0800
Dave, you wrote: "If I'm following this, N=87 should have tag=bet?"
If there's an entry in the "tag" column, then you can display the star's data with the common name immediately to its right in that row. I should have added that I filled in common names for some of the bright stars, like Deneb, even though there is no way to display them that way. You can try out the options. Just go to the modified entry form I posted here: http://www.fer3.com/arc/USNO-data-NavList.html. Try object name "87". You'll get data for "bet peg" or beta Pegasi in the output page.
There is also an aspect of the software that adds nothing to the list but shows us how it searches for the names. If you enter just "bet" or "be" or even just "b", the output page will return data for "bet cet" or beta Ceti. This is the first "bet" in the bayer list. I don't include the "bet" tag in the table because it's not really an independent tag. It's merely evidence of the lookup algorithm. It produces the same output page as entering "4" for the object name. That star, in fact, has another traditional name, Diphda, and that name has the three-character tag "dip" so that's what's in the table. Entering "dip" as a body ID yields the same numerical data (same GHA, Dec, etc.) but labeled with "Diphda". You could just ignore the tag column completely if you don't care about seeing the traditional names. They don't generate any new numerical data.
Maybe I should describe it another way. You can enter any of the numbers in the N column as a body ID. You can enter any of the three-letter codes in the tag column as a body ID. Those produce all of the possible unique output pages. There are other codes that "accidentally" repeat some of the output pages. And of course there are the body ID codes I listed earlier for today for the planets (plus non-planet Pluto). Shortened to three letters, they are sun, moo, mer, ven, ear, mar, jup, sat, ura, nep, plu. And there are two group codes all and ss which I also described earlier. And that's all the three-character codes that produce independent, unique output pages. That's all there is.
I'm not suggesting there's anything important in this. It's just fun to see what data you can get from the "official" USNO celestial navigation data web tool. It's mostly what you would expect with some oddball exceptions, like G Sco and N Vel and Pluto. They're hidden because they are officially and quite reasonably not important.