TITLE: GCN CIRCULAR NUMBER: 907 SUBJECT: H band observation of GRB 001212 DATE: 00/12/22 17:59:41 GMT FROM: Jochen Greiner at Astrophys.Inst. Potsdam,Germany J. Greiner, G. Szokoly (both AIP, Potsdam), J. Eisloeffel, B. Stecklum, S. Klose (all TLS, Tautenburg), Th. Stanke (MPIfR, Bonn), N. Lodieu, M. McCaughrean (both AIP, Potsdam), A.J. Castro-Tirado (LAEFF-INTA, Madrid and IAA-CSIC, Granada), report: We have observed the error box of GRB 001212 (GCN #899) on Dec. 15, 2000 (2.5 days after the GRB) and Dec. 17, 2000 with the 3.5m telescope of the German-Spanish Calar Alto Observatory. The observations were done with the NIR-camera Omega-Prime in the H band. Two adjacent pointings were made with the 6.5 arcmin FOV camera, covering about 90% of the error box (see the image at http://www.aip.de/~jcg/grb001212.html). Conditions were non-photometric during the first night. Photometric calibration of the images was done based on the 2MASS magnitude of object 2MASS 0649178+362151 having H = (14.45+-0.06) mag (and a USNO R-band magnitude of 16.1 mag). A comparison of the two epochs of (summed) H-band images of GRB 001212 reveals no object in the GRB error box which faded by more than 0.2 mag down to H = 18.3 mag. ----------------------------------------------------- Date (UT) exposure (min) seeing limiting (Start) Poin1 Poin2 (arcsec) mag. ----------------------------------------------------- Dec. 15.1744 32 32 3.0 H = 18.3 Dec. 17.8188 6 7 1.3 H = 18.4 ----------------------------------------------------- The object mentioned by Mohan et al. (GCN #900) which was reported by Gizis (GCN #901) to have H = (14.603+-0.083) mag based on the April 1, 1998 2MASS scan, was measured with H = (14.45+-0.10) mag and H = (14.50+-0.10) mag at the two epochs, thus being constant within our measurement errors. We appreciate the availability of the 2MASS 2nd Incremental catalog at IPAC/Caltech.