TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4139 SUBJECT: IPN triangulation of GRB051022 (=H3950) DATE: 05/10/22 18:59:28 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses and Mars Odyssey GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara, and R. Starr, on behalf of the GRS-Odyssey GRB team, and E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, report: Mars Odyssey and Konus-Wind observed GRB051022 (=H3950, GCN 4131 and 4137). We have triangulated it to an annulus centered at RA, Decl(J2000)=47.9138, +16.5422 degrees, whose radius is 46.4533 +/- 0.0684 degrees (3 sigma). The center line of this annulus passes 0.004 degrees from the HETE SXC position, and the annulus just encompasses the SXC error circle, without substantially reducing its area. We also confirm that this burst was exceptionally bright, and that its duration, as observed by HEND (>~50 keV), was about 200 s. More details will follow.