[vsnet-obs 24476] Sequence for SN 1999em

["Berto Monard" <lagmonar@csir.co.za>]

Hi, 

thanks to the efforts of Arne Henden, we can now use an accurate sequence for monitoring the SN 1999em photometric evolution. 
I assume the values are better than 0.1 magnitude. The measured value of the SN was 13.7 V (much fainter than the visual observations) and its blue colour is given as B-V = 0.1.
 
From Arne's data I derived the following sequence around galaxy NGC 1637. Notice the good agreement of these measures with those shown on the AAVSO chart. Unfortunately those two stars are red and not very good comparaison stars for the blue supernova, but they are nearby.

(2000) RA , DE, V, B-V

044132-024942, 12.35 (1.22)    
044117-024747, 12.80 (0.17)
044117-025530, 12.85 (0.78)
044130-024808, 12.97 (1.17)
044124-024552, 13.57 (0.88)
044117-024650, 13.75 (0.85)
044122-024536, 13.87 (0.72)
044119-024803, 14.19 (0.71)
044120-024806, 14.28 (0.67)
044140-024939, 14.83 (0.80)
044125-025036, 15.06 (0.62)

I hope you'll use them in your observations so that we have an accurate and coherent set of measurements.

I hereby wish to retract my previously reported observation estimates based on the VSNET sequence:

SN1999em   991101.994   131   MLF
SN1999em   991102.90    131   MLF
SN1999em   991104.03    130   MLF    

and replace them with : 

SN1999em   991101.994   134   MLF
SN1999em   991102.90    134   MLF
SN1999em   991104.03    133   MLF    

Best regards,

Berto Monard
Pretoria

Perhaps I am copying the effort of someone else in sending this e-mail, but since I did not receive any mail since yesterday morning I do not know about it...

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