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Date: Tue, 31 Aug 1993 08:35:02 -0700 (PDT)
From: ZHOUXU%BEPC2@SCS.SLAC.STANFORD.EDU
Subject: Re: VS observations
UBVRI photometric observation of supernova 1993J
Further observation of SN1993J were done with the camera attached to the
60/90cm Schmidt telescope in Xing-Long station of Beijing Astronomical
Observatory and a Ford CCD with 2048x2048 15um pixel as detector. The
field size of CCD image is about one square degree.
The UBVRI Photometric Landolt Standards (1983) were used to transform
our data into the Johnson system.
The data reduction was carry out by using IRAF and using photometry
for stars GSC 4383.n in the vicinity of the supernova as standards.
UBVRI values of these stars were provides by H. G. Corwin (1993,
IAUC.5742). Mean internal standard deviations are no more than
+/- 0.03 mag, and none of the stars shows evidence of variability.
Corwin's R and I value were in the Cousins system and before used for
calibrat SN1993J magnitude, these value was transformed into Johnson
system by using the formular given by Bessel (1979).
(V-R)c=0.73(V-R)j-0.03 for (V-R)j<1.0
and (V-I)c=0.778(V-I)j for 0<(V-I)j<2.0
date U err B V R I observer
Aug07.67 14.37 0.50 14.43 13.61 13.21 12.83 Yan,H.J., ZHOU Xu
Aug08.73 15.20 0.50 14.43 13.63 13.21 12.85 Yan,H.J., ZHOU Xu
Aug13.53 14.44 13.67 12.99 12.65 Wu,H., Li,Y.
Aug23.37 14.44 13.81 13.21 12.71 Fan,X.H.
Aug27.47 14.57 13.91 13.30 12.77 ZHOU Xu
Aug28.80 14.83 0.20 14.49 13.87 13.27 12.81 ZHOU Xu
Aug29.57 14.59 14.01 13.34 12.98 ZHOU Xu
The errors are less than +/- 0.03 except U band.
*** REPORT BY ZHOU XU ***
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