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Date: Fri, 16 Apr 93 12:20:00 JST
From: Hitoshi Yamaoka <g78261a@kyu-cc.cc.kyushu-u.ac.jp>
Subject: visual estimate 14 Apr.
From: sheaffer@netcom.com (Robert Sheaffer)
Newsgroups: sci.astro
Subject: Re: Observations of SN 1993J
Date: 14 Apr 93 23:00:40 GMT
Organization: Netcom - Online Communication Services (408 241-9760 guest)
I observed SN 1993J the past two nights (approx. April 13.2 and April 14.15)
using a 12.5" reflector under less-than-pristine suburban skies. It is
noticeably brighter than either of the two nearby stars, whose magnitudes
were given in a recent post as 12.3 and either 11.4 or 11.9 (the catalogs
disagree, so call it 11.75). If these numbers are accurate, and if
we estimate the SN as about a half-magnitude brighter, then it still is
not brighter than mag. 11. If, however, the SN is closer to a full
magnitude brighter (hard to estimate!), it may be as bright as 10.8.
The GIF that Mr. Richmond has made of M81
and made available via FTP looks beautiful on my SVGA. The only possible
improvement might to be to have an arrow or something indicate the
supernova for those who don't have any charts to refer to. Incidentally,
the Webb Society Deep-Sky Observer's Handbook (Vol. 4, p. 172) has a
drawing of NGC 3031 (M81) made using a 6" telescope at approx. 100 power.
It shows the two nearby stars mentioned above; if you look tonight,
you'll see three stars!
--
Robert Sheaffer - Scepticus Maximus - sheaffer@netcom.com
Past Chairman, The Bay Area Skeptics - for whom I speak only when authorized!
"Marxism and feminism are one and that one is Marxism"
- Heidi Hartmann and Amy Bridges,
quoted by Catharine MacKinnon above the first chapter
of her "Toward a Feminist Theory of the State"
--- 8< --- 8< --- 8< --- 8< --- 8< ---
From: sheaffer@netcom.com (Robert Sheaffer)
Message-ID: <vsnet-history738@hoge.baba.hajime.jp>
Subject: Re: Observations of SN 1993J
To: g78261a@kyu-cc.cc.kyushu-u.ac.jp (Hitoshi Yamaoka)
Date: Thu, 15 Apr 93 10:37:51 PDT
In-Reply-To: <9304150945.AA15085@kyu-cc.cc.kyushu-u.ac.jp>; from "Hitoshi Yamaoka" at Apr 15, 93 6:45 pm
X-Mailer: ELM [version 2.3 PL11]
Status: R
Hitoshi Yamaoka
>
> The refined photometry by T. Kato, Kyoto Univ. (private communication)
> says that the nearby stars of SN 1993J are about 11.40 and 11.90 in V band.
> So, your observation says that SN on that day would be 10.9 - 10.4 mag.
> Oh, bright! It is comparable with the first maximum at 31-March.
>
> By the way, T. Kato and I are making light curves with numerous observations
> from whole world. Can we add your observation to our list? If you agree,
> please notice me about your observation times and magnitudes (are they same
> for April 13.2 and 14.15? Are these in UT?). If you do not agree, please
> notice it also. Our table will be circulated to all over the world for
> professionaly use.
Yes, the times I gave are in UT (approximate), i.e. .15 (actually .167)
would be 1/6 of a day, or 4 hours UT. I did not make a careful observation
on Apr. 13; use only the Apr 14, 04:00 UT. The SN is definitely brightening
since it started to fade. It may have even been brighter on Apr 14 than the
previous night, although I am not certain of that. The difference in
brightness between the SN and the 11.4 star was greater than the difference
between the 11.4 and 11.9, so yes, it must have been somewhere around
10.8-10.5.
Last night it was cloudy here. Now ( Thurs. morning) it is clear again.
If it is clear tonight, I will observe again, and post the result.
You are welcome to use my observations (however inaccurate they may
be!) in any way you choose.
--
Robert Sheaffer - Scepticus Maximus - sheaffer@netcom.com
Past Chairman, The Bay Area Skeptics - for whom I speak only when authorized!
"Marxism and feminism are one and that one is Marxism"
- Heidi Hartmann and Amy Bridges,
quoted by Catharine MacKinnon above the first chapter
of her "Toward a Feminist Theory of the State"
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