(IAAC) Visual confirmation of a Gamma-Ray Burst "Optical Transient"

I thought this might make an extremely intriguing visual deep-
sky observing project for some of our more patient readers!

Clear skies,
Lew Gramer

-----Original Message-----
Subject: [AAVSO-DIS] GRB 030329: visual observations
Date: Sun, 30 Mar 2003 13:39:58 +0300
From: Arto.Oksanen@tietoenator.com
CC: aavso-discussion@informer2.cis.McMaster.CA,vsnet-chat@kusastro.kyoto-u.ac.jp

Dear All,

Please find my GCN GRB observation report bellow. This is very probably the
first ever visual observation of a gamma-ray burst optical afterglow!

When I received the first reports of this very bright (R=12.4) and well
positioned (in Leo) optical transient (OT) it was late afternoon in Finland.
But, of course, our sky was completely clouded and the weather forecast
promised even more clouds with possible rain or snow for the night. There
was still some possibility that southern and western Finland would have
better conditions, so I alerted as many variable star and Deep Sky observers
as possible to observe this very rare event.

Two very experienced DS-observers, Markus Tuukkanen and Riku Henriksson,
took their large mobile telescopes and went looking for clear sky. Both
reported live on their mobile phones soon after dark, around 20 UT, that
they were seeing the OT as a 14.3 magnitude stellar object on their
eyepieces! The quickly worsening weather at both sites did not allow long
observations so neither was able to see the OT fading. Also no obvious fast
flickering or color was seen.

Both observers made sketches of the GRB030329 field and the drawings are or
will be posted to the Deep Sky Archive http://archive.ermiksson.net/.

I would be very interested to know if anyone else has seen this (or any
other) GRB afterglows visually. It should have been easy target in
especially in the Far East when it was blazing at 13 magnitudes during the
first hours.

Personally I was trying to observe the OT with a CCD at Nyrola Observatory
from 19 to 24 UT. From the total of 148 images only about 50 taken during
the periods of thinner clouds show the afterglow. Image analysis is in
progress. And yes, it was snowing when I closed the observatory!

best regards,

Arto Oksanen                       mailto:arto.oksanen@jklsirius.fi
Jyvaskylan Sirius ry, Kyllikinkatu 1, FIN-40100 Jyväskylä,  Finland
Tel. +358-14-4157852, Mobile: +358-40-5659438, Fax: +358-14-4157803
Nyrola Observatory    http://www.ursa.fi/sirius/nytt/nytt_info.html

-----Original Message-----
NUMBER:  2010
SUBJECT: GRB 030329: visual observations
DATE:    03/03/30 00:33:03 GMT
FROM:    Arto Oksanen at Nyrola Obs., Finland <oksanen@nyrola.jklsirius.fi>

A. Oksanen (Nyrola Observatory), R. Henriksson and M. Tuukkanen (the Finnish
Deep Sky section of Astronomical Association Ursa) report:

We observed the optical afterglow of GRB030329 reported by Peterson and
Price (GCN 1985) visually about 8 hours after the burst.

M. Tuukkanen observed the OT In Pornainen, Finland with a 0.63 m Newton
telescope for about one hour starting March 29, 2003 19:30 UT.
He reported it as a faint starlike object seen easily with direct vision. He
did not see any flickering or distinct color.

R. Henriksson was observing in Orivesi, Finland with his 0.30 m Newton
telescope using 200x magnification at 20:05 UT. He reported the object
stellar and faint, visible only with averted vision. His scanned sketch
with notes is available on web:


Both observers estimated the visual magnitude as 14.3 by using the 14.2
magnitude GSC 1434:322 star North of OT as reference.

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