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Date: Mon, 5 Apr 93 09:46:54 EDT
From: David Kratz <kratz@aquila.larc.nasa.gov>
Hitoshi:
You are very welcome to use my visual measurements of the SN1993J for
whatever purpose you deem suitable. I have included with this message both
observations made to date (I'll keep you posted on all further observations)
along with some information which you might find useful. Good luck in your
endeavor.
Sincerely,
Dave Kratz
Date Time (UT) Telescope Eyepiece comparison *'s mag estimate
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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
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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.
Comparison stars:
star mag. position from center of M81 on supernova chart by Thompson & Bryan
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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
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