[vsnet-chat 3602] Re: Position of SN 1972L in NGC 735

[Hitoshi YAMAOKA <yamaoka@rc.kyushu-u.ac.jp>]

B. Skiff wrote (in ISN_chat):

>     I have compared the Kowal et al. image of SN 1972L with the DSS,
>and estimate the following position for this event:  1 56 40.6  +34
>10 14 (2000). The uncertainty is something like 3", perhaps  as much
>as 5".  Using the GSC-ACT position for the galaxy nucleus and the
>nominal offset for the object (28" east, 21" south), I get:  1 56
>40.2  +34 10 15. 

  G. Sostero has kindly show his image of SN 2000dj, with which I got
the coordinates of SN 2000dj as: R.A. = 1h56m40s.56, Decl. =
+34o10'12".4, based on 44 USNO-A2.0 stars around the galaxy.  The
uncertainty would be below 1".  The KAIT position is slightly (0".7)
east of mine, but the difference isn't so large.  The background light
from the host galaxy can bring the position of SN westward.

>     Since there is photometry for three stars in the immediate
>field, it is easy to estimate that the Kowal image shows the SN at 
>V=16.0, with uncertainty less than 0.1 mag.  If this is as bright as
>the object got, then its magnitude has been overestimated (assumed to
>be too bright).  The Palomar SN survey used yellow-sensitive IIa-D
>films, so the images are basically V-band pictures.

  I agree.  But, as you mentioned, it is not certain whether the plate
in Kowal et al.'s paper is the one at the discovery ;-).

Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
yamaoka@rc.kyushu-u.ac.jp

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