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Re: Lewis and Clark lunars: more 1803 Almanac data
From: Ken Muldrew
Date: 2004 Apr 19, 16:10 -0600
From: Ken Muldrew
Date: 2004 Apr 19, 16:10 -0600
On 18 Apr 2004 at 23:50, Paul Hirose wrote: > Right ascension of the star would be 4 h 50 m by my calculation. 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. Perhaps through a good telescope a magnitude 4.47 star can look like Aldebaran? Here are the results of my calculation for PI 6 Orion: GMT clr'd d true d 5.094 59.697 59.605 5.323 59.758 59.705 5.493 59.831 59.795 5.589 59.839 59.831 5.643 59.923 59.865 5.694 59.938 59.888 7.267 60.544 60.625 7.362 60.619 60.680 7.419 60.600 60.698 7.490 60.607 60.732 7.525 60.636 60.757 7.571 60.638 60.770 The error for the first run (series A) averages out to about a minute, well within the expected limit. The error for the second run (series C) is a bit larger, and increasing, so they may indeed have used another nearby star for this series as George has speculated, although the error is comparable to what they got for Regulus in series B. Ken Muldrew.
