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(IAAC) Supernova observations April27/28



Subject: Supernova observations, April27/28 1998
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I have managed to make another set of observations of the Ursa Major
supernovae last night April27/28 both at about 02.00UT. once again the
objects were virtually at the zenith so no extinction corrections should be
needed. I gave the dates in the AAVSO format which requested Julian dates.
Observations on SN 1998aq, SN 1998S 20" F4.4 Newtonian on Dobsonian mount,
Sky clear limiting magnitude 6.2
Object   name   Julian date      Magn.            Compstars       Chart
SN 1998aq   -  2,450,932.5800    11.8             10.7 12.1 12.2 12.4  AAVSO  
SN 1998S       2,450,932.5800    13.4             12.5 12.6 13.2 13.8  AAVSO
1998S has decreased noticeably in brightness over the 3 day period and is
distinctly dimmer than the neighbouring 13.2 magnitude star on the AAVSO
provisional comparison chart.
1998aq has brightened by 0.4 magnitude at least by my estimate, this was
based on an estimation of how much brighter the supernova was than the
magnitude of the 12.1 comparison star on the AAVSO chart compared with the
brightness step between this 12.1 star and a 12.4 star on the AAVSO chart.
The SN was roughly equal in brightness to the brighter of a group of four
stars which include the magnitude 12.2 and 12.4 comparison stars.
Unfortunately no figure is given on the chart for this star.
Nick