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Date: Mon, 10 May 93 01:21:55 -0400
From: mcdavid@aip.org (david_mcdavid)
Subject: SN phot
Hello Taichi Kato -
Here is some CCD photometry data on SN 1993J that I am sending for your
compilation on the advice of Craig Wheeler of the University of Texas
at Austin. I have a B.S. in Physics from Stanford University (1972)
and an M.A. in Astronomy from the University of Virginia (1977), was a
faculty member at the University of Texas at San Antonio for 15 years,
and have now retired to my private home observatory in the country,
which I named in honor of D. Nelson Limber (one of my teachers at
Virginia).
I have a 16-inch Cassegrain telescope with a thermoelectrically cooled
Photometrics CCD camera based on a coated Thompson 512x512 chip
(TH7895). I'm using the so-called "Harris filter set" (KPNO Newsletter
No. 12), with extinction and transformation coeeficients determined by
matching to Schild's M67 standard sequence (PASP 95, 1021). The rms
error of the fit to 11 stars is 0.02 mag in both V and B-V. The data
reduction was done using the IRAF software package.
As a comparison star for the supernova, I have used GSC 4383.0928, with
Corwin's values of V=11.90 and B-V=0.50 (IAUC 5742). Each measurement
in the table is derived from the means of at least 3 repeated B and V
frames, and the "err" value is the square root of the sum of the
squares of the standard deviations in the raw B and V magnitudes. As a
check star, I measured GSC 4383.0565 for every supernova set, with
results of V=11.40+/-0.01 and B-V=0.56+/-0.01 for the means and
standard deviations of the 18 matching data points.
- David McDavid
Limber Observatory
Pipe Creek, Texas, USA
UT Date V B-V err B
----------- ----- ---- ---- -----
April 01.40 11.11 0.25 0.02 11.36
02.13 11.33 0.31 0.02 11.64
02.32 11.40 0.31 0.02 11.71
02.40 11.43 0.34 0.02 11.77
05.12 11.86 0.38 0.03 12.24
05.26 11.86 0.41 0.02 12.27
05.37 11.85 0.41 0.03 12.26
06.11 11.82 0.41 0.04 12.23
06.24 11.81 0.40 0.04 12.21
08.11 11.61 0.43 0.01 12.04
09.28 11.46 0.47 0.01 11.93
10.28 11.34 0.46 0.02 11.80
11.13 11.23 0.48 0.02 11.71
11.29 11.22 0.46 0.01 11.68
15.18 10.91 0.48 0.02 11.39
16.31 10.85 0.53 0.01 11.38
18.12 10.82 0.58 0.01 11.40
21.12 10.91 0.72 0.02 11.63
* * * * *
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