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[vsnet-chat 2185] SN1999cp field photometry
- Date: Tue, 27 Jul 1999 09:10:18 +0200
- To: vsnet-chat@kusastro.kyoto-u.ac.jp
- From: Berto Monard <lagmonar@csir.co.za>
- Subject: [vsnet-chat 2185] SN1999cp field photometry
- Cc: kevin@astro.washington.edu, aah@nofs.navy.mil
- Disclaimer: The CSIR exercises no editorial control over E-mail messages originating in the organisation and the views in this message are therefore not necessarily those of the CSIR and/or its employees.
- Sender: owner-vsnet-chat@kusastro.kyoto-u.ac.jp
Hi Arne,
Your efforts are again greatly appreciated.
The magnitudes derived by yourself and Kevin are identical as far a
visual sequence (at 0.1 mag resolution) is concerned...and they prove
indeed that the VSNET sequence is about 0.3 to 0.4 magn too faint as I
expected. What are we going to do about it, Taichi?
Tonight I'll prepare and send a comparison table, that is if Bruce
Sumner doesn't beat me to it, which I hope he does!
I take this opportunity to state that the method of calibrating
USNO-A2.0 measures to nearby GSPC or other calibrated starfields has
worked very well for a number of sequences. But for other sequences
this wasn't the case. Perhaps the GSPC field was too remote or the
USNO measures didn't belong to the same 'plate' or were derived from
the edge of the plate or whatever. Fact is that such sequences didn't
stand the penultimate test, ie the look from behind the eyepiece which
I consider reliable to far better than 0.5 magnitude (in absolute
terms ...). This could be argued but I am convinced of it.
However there is no substitute for properly conducted CCD measurements
vs a standard.
With my very best regards,
Berto Monard
Pretoria
>>> <aah@nofs.navy.mil> 07/26 11:45 PM >>>
skip...
Note, however, that the visual sequence is in agreement between
the datasets and can be considered reliable. I haven't checked
its value with respect to the VSNET sequence; someone (Berto?) should
do so to see if there is an offset in the VSNET sequence. Only
CCD observers should be concerned about the (B-V) dilemna.
Sorry about the length of this posting, but Brian started it!
Arne
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