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Re: Lewis and Clark lunars: more 1803 Almanac data
From: Frank Reed CT
Date: 2004 Apr 21, 17:33 EDT
From: Frank Reed CT
Date: 2004 Apr 21, 17:33 EDT
Ken M you wrote:
"I had another look at a star chart over lunch and found a small, dim, red star at the bottom of Orion's bow (PI 6 Orion) with an 1803 right ascension of 4h 48m 23.5s, dec 1° 24' 5.7". I stuck that into my spreadsheet where I was comparing the cleared distance with the true distance for various stars (in my post of this morning) and it appears to be our mystery star. "
Though this is possible, I'm skeptical for a couple of reasons. First, this is a very faint star. That bright gibbous moon would make it extremely difficult to see. What worries me more is that this may have become a case of a solution that fits the data by mere chance. Your standard of solution was to seek a star that would fit the distance and rate of change of the observations to within a few minutes of arc. There are two patches of sky that would do this, as a matter of mathematical necessity. How large are those patches? What is the probability that you will find a star brighter than magnitude 5.0 (or some other limit) merely by chance in one of those patches? Indeed, is there a star in the patch on the opposite side of the ecliptic that is as bright as Pi 6 Ori?
All that said, I think it's still a possibility. Is there some methodological error that would have led to this star instead of Aldebaran? Do any of the stars near Pi 6 Ori make a pattern that might be mistaken for the Hyades (possibly inverted) by an inexperienced observer? Aldebaran is one of the easiest lunars stars to identify because of the distinctive pattern around it, and that pattern is well-described in Moore/Bowditch etc.
Frank E. Reed
[ ] Mystic, Connecticut
[X] Chicago, Illinois
"I had another look at a star chart over lunch and found a small, dim, red star at the bottom of Orion's bow (PI 6 Orion) with an 1803 right ascension of 4h 48m 23.5s, dec 1° 24' 5.7". I stuck that into my spreadsheet where I was comparing the cleared distance with the true distance for various stars (in my post of this morning) and it appears to be our mystery star. "
Though this is possible, I'm skeptical for a couple of reasons. First, this is a very faint star. That bright gibbous moon would make it extremely difficult to see. What worries me more is that this may have become a case of a solution that fits the data by mere chance. Your standard of solution was to seek a star that would fit the distance and rate of change of the observations to within a few minutes of arc. There are two patches of sky that would do this, as a matter of mathematical necessity. How large are those patches? What is the probability that you will find a star brighter than magnitude 5.0 (or some other limit) merely by chance in one of those patches? Indeed, is there a star in the patch on the opposite side of the ecliptic that is as bright as Pi 6 Ori?
All that said, I think it's still a possibility. Is there some methodological error that would have led to this star instead of Aldebaran? Do any of the stars near Pi 6 Ori make a pattern that might be mistaken for the Hyades (possibly inverted) by an inexperienced observer? Aldebaran is one of the easiest lunars stars to identify because of the distinctive pattern around it, and that pattern is well-described in Moore/Bowditch etc.
Frank E. Reed
[ ] Mystic, Connecticut
[X] Chicago, Illinois
