TITLE: GCN CIRCULAR NUMBER: 6873 SUBJECT: GRB 071010B possible optical transient DATE: 07/10/10 22:53:58 GMT FROM: AAVSO GRB Network at AAVSO A. Oksanen (Nyrola Observatory, Jyvaskyla, Finland) reports to the AAVSO International High Energy Network the following optical observations of GRB071010B (GCN #6871, Markwardt et al.): Arto Oksanen reports the detection of an optical transient located at RA 10:02:9.26, Dec +45:43:50.3 (J2000) at an initial unfiltered magnitude of 17.538 calibrated relative to USNOB R-band magnitudes. Midpoint of the exposures is 2007 Oct 10, 21:11:05 UTC, approximately 25 minutes after the trigger. There are no comparably bright stars within 0.5 arcminutes, and no minor planets in the area. Subsequent unfiltered images place the star fainter than 18th magnitude (unfiltered) indicating the object has faded since observations began. Analysis of additional unfiltered, Rc, Ic, and V images will be forthcoming. The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network.