[vsnet-grb-info 25467] GRB 200412B: Tautenburg observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27567
SUBJECT: GRB 200412B: Tautenburg observations 
DATE:    20/04/13 12:26:07 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose at tls-tautenburg.de>

B. Stecklum, S. Klose, S. Melnikov, and A. Nicuesa Guelbenzu (all 
Tautenburg) report:

We observed the field of GRB 200412B (Fermi GBM team, GCN 27547; Mailyan 
et al., GCN 27558; see also Burgess et al., GCN 27548; Longo et al., GCN 
27557; Page et al., GCN 27561; Gupta et al., GCN 27563; Zheng et al., GCN 
27565) with the Tautenburg 1.34m Schmidt telescope equipped with the 
TAUKAM 6k x 6k CCD camera and the wide V-band filter (VB). The 
transmission curve of this filter closely follows the Gaia GBP filter.

The fading optical transient detected by MASTER Global Robotic Net 
(Lipunov et al., GCN 27555, 27556) is clearly detected on our images (for 
other optical observations see also Kumar et al., GCN 27564; Belkin et 
al., GCN 27566). Using Gaia DR2 stars in the field, we measure the 
following preliminary magnitudes (Vega system):

Mean time: April 12, 21:29:48 UT, VB = 18.43 +/- 0.01
Mean time: April 13, 02:22:38 UT, VB = 19.00 +/- 0.01