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Date: Thu, 20 May 1993 13:49:13 +0200
From: granslo@argo.uio.no
Subject: SN 1993J - Spanish observations and photometric update
Blindern, Oslo, 1993 May 20
Guy Hurst
Taichi Kato
Gerard de Vaucouleurs
Ralph Wijers
I have received the following fax report from Jose Ripero:
>Dear Bjorn Granslo,
>
>With this letter I enclose our last observations of SN 1993J. I also send
>you an updated version of our official list of observations. There are
>several corrections:
>
>1. Observations by Diego Rodriguez: D. Rodriguez has, in accordance with
>Dr. Vaucouleurs' recommendation, used several comparison stars. For this
>reason some of his magnitudes have been revised.
>
>2. Your photometric list of observations, report #7: Three observations
>by F. Garcia are listed for March 28. Only two of them are real, on
>21.45 U.T. (discovery observation) and 23.35 U.T. The observation at
>20.45 U.T. (March 28.86 U.T.) is not correct. I hope you can excuse me for
>this error. You can use the enclosed list to check the facts. There are
>also another minor changes for the other observations as we have used new
>sequence stars.
>
>I would like to remark that the enclosed list is our last and updated
>official list of observations. It includes all relevant parameters,
>such as date, time, brightness, comparison stars etc. This list cancel any
>previous lists of observations. I will also send the updated list to our
>other contacts such as AAVSO, Dr. Vaucouleurs etc.
>
>We also send you a preliminary light curve with our observations.
>
> Sincerely,
> Jose Ripero
> (sign.)
> M 1 SN Search Group MAA
>COMMENTS ABOUT THE LIST OF OBSERVATIONS OF SN 1993J MADE BY MEMBERS OF THE
>M 1 GROUP
>
> - We have always used Argelander's step method for the brightness estimates
> and the average magnitude is listed.
>
> - Magnitudes of sequence stars are taken from the AAVSO SN search chart for
> 0947+69 NGC 3031. This chart was enclosed with AAVSO Alert Notice #171.
>
> - The observations by D. Rodriguez are unfiltered CCD magnitudes. Following
> the recommendation by Dr. Vaucouleurs he has used three comparison stars
> to obtain the magnitude of the SN and the average magnitude is listed.
>
> - List of telescopes:
> FRAN GARCIA. Newtonian 25-cm, f/3.9, Nagler 9/13 mms.
> DIEGO RODRIGUEZ. Newtonian 20-cm, f/4, CCD Camera.
> FRANCISCO PUJOL. Newtonian, 31-cm, f/5, Koenig 16 mm.
> JOSE RIPERO. Dobsonian 33.5-cm, f/4.5, Nagler 9/12 mms.
> JOSE CARVAJAL. Dobsonian 31-cm, f/4.5, Nagler 9/12 mms.
> DOLORES GARCIA. Newtonian 25-cm, f/3.9, Nagler 9/13 mms.
>
> - List of comparison stars:
> *A = 9.4; *B = 10.4; *B1 = 10.3; *C = 10.8; *D = 11.7;
> *D1 = 11.8; *E = 11.4; *D = 11.7; *D1 = 11.8; *H = 12.4;
> *I = 12.9; *I1 = 12.9; *J = 13.0; *K = 13.6; *L = 13.7;
> *M = 13.8; *N = 13.9; *O = 14.0; *P = 14.6; *Q = 14.8;
> *R = 14.9; *S = 15.0; *S1 = 15.0; *T = 15.3.
I am now preparing to distribute version #9 of my list of SN 1993J
observations. It will also include the revised observations by the
Spanish group. Their magnitudes are taken from their last list, but
the times have been calculated to three decimal places for sorting
purposes.
A copy of this letter will be sent to Jose Ripero.
Kind regards,
Bjorn H. Granslo
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