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Re: TEN lunars stars?
From: Frank Reed CT
Date: 2003 Dec 17, 21:01 EST
From: Frank Reed CT
Date: 2003 Dec 17, 21:01 EST
Herbert Prinz wrote:
"One cannot blame Maskelyne for trying alternatives to Altair, but why
not Sigma Sag. (Nunki)? With an ecliptic longitude of 282 deg, it is as
far from Antares as Beta Cap. is from Fomalhaut, but it is a whole
magnitude brighter than Beta Cap."
Interesting question. As your table shows, it's brighter than Markab, and it would be a good choice especially for observers in southern latitudes. In order to be useful for lunars, the ecliptic longitudes and latitudes and the proper motion of the star have to be known accurately. Possibly there was some problem with the astrometry on Nunki in the late 18th century when the list was first compiled.
Incidentally, I counted up the days. There are lunars for Beta Cap on a grand total of 18 days in 1778 --some in March and April and a few more in June and July.
And you wrote:
"Some relief came in 1823 when Schumacher started publishing the
distances to the four navigational planets. Does anybody know the exact
year when these distances were included in the French and English
almanacs?"
I've got 1834 in my notes (which would apply to the British Nautical Almanac). I'm not aware of any other changes in the list of objects intended for observation until the end of lunars.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
"One cannot blame Maskelyne for trying alternatives to Altair, but why
not Sigma Sag. (Nunki)? With an ecliptic longitude of 282 deg, it is as
far from Antares as Beta Cap. is from Fomalhaut, but it is a whole
magnitude brighter than Beta Cap."
Interesting question. As your table shows, it's brighter than Markab, and it would be a good choice especially for observers in southern latitudes. In order to be useful for lunars, the ecliptic longitudes and latitudes and the proper motion of the star have to be known accurately. Possibly there was some problem with the astrometry on Nunki in the late 18th century when the list was first compiled.
Incidentally, I counted up the days. There are lunars for Beta Cap on a grand total of 18 days in 1778 --some in March and April and a few more in June and July.
And you wrote:
"Some relief came in 1823 when Schumacher started publishing the
distances to the four navigational planets. Does anybody know the exact
year when these distances were included in the French and English
almanacs?"
I've got 1834 in my notes (which would apply to the British Nautical Almanac). I'm not aware of any other changes in the list of objects intended for observation until the end of lunars.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
