TITLE: GCN CIRCULAR NUMBER: 10137 SUBJECT: GRB 091029: Observations from Stardome Observatory DATE: 09/11/05 08:44:38 GMT FROM: Antonio Deugarte at IAA-CSIC G. W. Christie (Stardome Obs., New Zealand), S. Dong (IAS, Princeton), A. de Ugarte Postigo (INAF-OAB, Italy) and T. Natusch (Stardome Obs., New Zealand) report: We observed the field of GRB 091029 (Swift trigger 372210, Grupe et al. GCN 10097) with the Stardome 0.4m telescope located in Auckland (New Zealand) starting at 07:55UT, 3.90 hours after BAT trigger. We used a SG530 filter that transmits wavelengths above 5300 Angstroms and a SBIG ST-L-6303E CCD (KAF-6303E detector). A nearly continuous series of 300s images was taken until 16:30UT under mostly clear conditions (seeing: 1.6-2.5"). These were co-added making 15 stacks of 6 images (1800s exposure each). The fading afterglow (Filgas et al., GCN 10098; LaCluyze et al., GCN 10099; de Ugarte Postigo et al., GCN 10104; Marshall et al. GCN 10108) was clearly detected in all images over the observing period, yielding the following psf photometry(DOPHOT): UT (mid) delT R1 Err (statistical) 29.32713 3.901 19.34 0.09 29.34906 4.428 19.32 0.08 29.37120 4.959 19.43 0.08 29.39311 5.485 19.46 0.08 29.41503 6.011 19.67 0.08 29.43360 6.456 19.57 0.08 29.45862 7.057 19.73 0.08 29.50946 8.277 19.93 0.12 29.53164 8.809 19.94 0.09 29.56044 9.501 20.16 0.09 29.59390 10.304 20.21 0.11 29.61620 10.839 20.21 0.13 29.63853 11.375 20.36 0.16 29.66081 11.910 20.41 0.17 where delT is the mid-exposure time in hours since trigger. Photometric calibration was done against USNOB1 0340-0030262 RA (J2000.0): 04h 00m 38.61s, DEC( J2000.0): -55d 55' 37.3" assuming R1=16.40. The mean power-law index over this interval was -0.94 (+/-0.05). Astrometry of the images gave the afterglow position (UCAC2) as: RA (J2000.0) = 04h 00m 42.62s DEC (J2000.0) = -55d 57' 20.2" with an uncertainty of 0.18" This position is in agreement with Marshall et al. (GCN 10108) and Grupe et al. (GCN 10097).