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Date: Fri, 2 Apr 93 17:04:34 PST
From: hgcjr@ipac.caltech.edu
Subject: M81 photometric sequence
Dear Nova folks,
Gerard de Vaucouleurs has suggested that I send you a copy of
my UBVRI sequence for the M81 field. Please feel free to distribute
it to other observers who might find it of use. Best wishes,
Harold Corwin
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Star V B-V U-B V-R V-I n RA (B1950.0) Dec Chart ID
1 12.45 0.63 0.11 0.39 0.76 3 09 50 25.6 +69 15 38 12.4 overline
2 11.78 0.69 0.16 0.40 0.80 3 09 50 35.9 +69 20 04 11.8 overline
3 11.62 0.53 -0.04 0.33 0.69 3 09 51 21.2 +69 05 34 11.6 (near 14.1)
4 11.90 0.50 -0.08 0.30 0.60 2 09 51 36.1 +69 14 44 11.9 overline
5 13.65 0.57 -0.09: 0.34 0.69 3 09 52 11.1 +69 09 41 13.6 overline
6 11.85 1.30 1.29 0.68 1.29 3 09 52 39.7 +69 24 18 11.8 underline
7 14.73 0.46 0.12: 0.36 0.60: 3 09 53 17.7 +69 24 54 14.7 overline
The V-R and V-I are on Cousins's system. All the observations
were made in 1982 Nov, 1983 Feb, and 1983 Apr, with the 76-cm
reflector at McDonald Obs. There is no evidence of variability
for any of the stars. The three values marked with a colon have
each had a discordant measure rejected (the means with no
rejections are -0.04, 0.09, and 0.66, respectively). The mean
internal standard deviations for these seven stars only are
V: +-0.015
B-V: +-0.011
U-B: +-0.032 (no rejections)
+-0.014 (two rejections)
V-R: +-0.019
R-I: +-0.029 (no rejections)
+-0.018 (one rejection)
These are about the values that I expected based on error analyses
of other subsets of my McDonald photometry.
The positions are from the GSC (mean errors about 1 arcsec), and
the "Chart ID" refers to the label on the Thompson/Bryan N3031
chart.
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