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Date: Tue, 13 Apr 93 21:53:47 JST
From: Hitoshi Yamaoka <g78261a@kyu-cc.cc.kyushu-u.ac.jp>
Subject: visual obs.
>From kratz@aquila.larc.nasa.gov Tue Apr 13 21:37 JST 1993
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id AA09065; Tue, 13 Apr 93 07:48:00 EDT
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Date: Tue, 13 Apr 93 07:48:00 EDT
From: David Kratz <kratz@aquila.larc.nasa.gov>
To: g78261a@kyu-cc.cc.kyushu-u.ac.jp
Status: R
Hitoshi:
Here are my running observations of SN1993J. I was very surprised by
how bright the supernova appeared last night; SN1993J was as bright as I have
ever had a chance to observe it.
Dave
Previously unreported observation is marked by a star (*).
Date Time (UT) Telescope Eyepiece comparison *'s mag estimate
------------------------------------------------------------------------------
4/2 1:00 8"/f3.5 TVP 10.5+paracorr a = d > b > c > SN > e 10.6
4/4 2:00 8"/f3.5 TVP 10.5+paracorr a = d > b > c > e > SN 10.8
4/8 0:45 8"/f3.5 TVP 10.5+paracorr a > e > SN > f > h 11.5
4/13* 1:00 8"/f3.5 TVP 10.5+paracorr a = d > b > c > SN > e 10.6
------------------------------------------------------------------------------
Additional comments:
The 8"/f3.5 in combination with the 10.5 millimeter TeleVue Plossl & the
paracorr coma corrector yields 79 power.
4/2: SN1993J is fainter than comparison stars (a), (d), (b), (c), and brighter
than comparison star (e).
Strong interference from moonlight (magnitude limit 13.0--13.5).
AAVSO magnitude designation: 1c/SN/1e or 3a/SN/1e <---This means that
the difference in magnitude between comparison star (c) and SN1993J, and
the between SN1993J and comparison star (e) are equal; and that the
difference in magnitude between comparison star (a) and SN1993J is 3
times the difference between SN1993J and comparison star (e).
Observation made from the Yorktown Battlefield, Virginia, U.S.A.
4/4: SN1993J appears to be fainter than comparison star (e) by the same
magnitude that comparison star (g) is fainter than comparison star (f).
Very strong interference from moonlight (mag limit about 13.0).
AAVSO magnitude designation: 4a/1e/SN
Observation made from the Yorktown Battlefield, Virginia, U.S.A.
4/8: SN1993J appears to be brighter than comparison star (f) by half the
magnitude that comparison star (f) is brighter than comparison star (h).
AAVSO magnitude designation: SN/1f/2h
SN1993J also appears to be fainter than comparison star (e) by twice the
magnitude that comparison star (e) is fainter than comparison star (a).
AAVSO magnitude designation: 1a/2e/SN
Both of these comparisons lead to a magnitude estimate of 11.5.
Limiting magnitude 14.0 (magnitude 14.0 foreground star 30" SW of SN1993J
is just visible).
Observation made from the Yorktown Battlefield, Virginia, U.S.A.
4/13: SN1993J has brightened significantly since 4/8. SN1993J is fainter than
comparison stars (a), (d), (b), (c), and slightly brighter than comparison
star (e).
AAVSO magnitude designation: 1c/SN/1e or 3a/SN/1e
Observation made from the Yorktown Battlefield, Virginia, U.S.A.
Comparison stars:
star mag. position from center of M81 on supernova chart by Thompson & Bryan
------------------------------------------------------------------------------
a) 10.3 11.8' West 0.3' South
b) 10.4 3.3' West 7.2' South
c) 10.5 3.7' West 7.2' South
d) 10.3 12.4' East 7.5' South
e) 10.7 4.5' West 9.7' North
f) 11.8 4.2' West 2.0' North
g) 11.9 0.3' East 3.5' South
h) 12.4 5.5' West 2.1' South
-----------------------------------------------------------------------------
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