TITLE: GCN CIRCULAR NUMBER: 16228 SUBJECT: GRB 140508A: SAO RAS and MASTER photometric and spectroscopic observations DATE: 14/05/09 01:15:15 GMT FROM: Vladimir Sokolov at SAO RAS A. S. Moskvitin, D. I. Makarov, A. F. Valeev, V. V. Sokolov (SAO-RAS, Russia), A. J. Castro-Tirado, J. Gorosabel (IAA-CSIC, Spain), E. S. Gorbovskoy, D. V. Denisenko, V. M.Lipunov (MASTER-team, Russia), on behalf of a larger collaboration, report: "Following the detection of GRB 140508A by Fermi (Yu et al. GCNC 16224) and the IPN (Hurley et al. GCNC 16225), we have conducted BVRc imaging and spectroscopy of the iPTF optical candidate (Singer et al. GCNC 16226) with the 6m BTA telescope in Zelenchukskaia, starting at 19:47:56 UT (i.e. 16.7 hr after the trigger). The 20 minutes (noisy) spectrum, covering the range 3800-7200 A, displays no clear absorption features, i.e. a conservative upper limit of z < 2.1 is derived. The GRB OT magnitude was measured to have R = 18.7 +/- 0.05 during the BTA observations spanning more than 1 hr. OT magnitudes calibrated against the USNO-B1 star 1367-0290781 with R2 = 16.48. MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk also pointed to the GRB140508A (Yu et. al GCNC 16224, Hurley et. al. GCN 16224) ~17.5 h after trigger time at 2014-05-08 20:31:01.484 UT directly after sunset and weather conditions became satisfactory. On the first (180s exposure) unfiltred image the iPTF optical transient preliminary photometry is given below: T_start T-T_trig FILTER Mag Err.Mag Exptime 2014-05-08 20:31:01 17h 28m C 18.7 0.3 180 s 2014-05-08 20:48:33 17h 45m R 18.7 0.3 180 s 2014-05-08 20:48:33 17h 45m V <19.0 0.3 180 s upper limit 2014-05-08 21:20:36 18h 17m R 18.9 0.3 540 s 2014-05-08 21:20:36 18h 17m V 19.9 0.4 540 s "C" is unfiltred 0.8R+0.2B magnitude. This message can be quoted."