{
  "bibcode": "2009GCN..9907....1O",
  "body": "Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports to the AAVSO \nInternational High Energy Network the following optical observations of \nthe field of GRB090912 (GCN Circ. #9905, Ukwatta et al.):\n\nA. Oksanen reports an upper limit on the optical afterglow of CR=21.6, \nmeasured relative to USNO-A2.0 1500-05568008 (R=15.7).  The X-ray \nafterglow position (Beardmore et al., GCN #9906) was observed using the \n0.4-m Hankasalmi Observatory RC telescope with an SBIG STL-1001E CCD \ncamera and clear filter.  A total of 57 one-minute exposures were \nobtained, with the mid-point of the exposures at 2009 Sept 12 19:33 UT, \napproximately 3.7 hours post-burst.  Two faint stars near the burst \nlocation are present in DSS2 images, but there is no transient source at \nthe burst location to a limit of CR=21.6.\n\nA detailed report of these observations may be found at the following URL:\nftp://ftp.aavso.org/grb/ArtoOksanen_GRB090912_2455087.38910_.txt\n\nA fits image is also available at\nftp://ftp.aavso.org/grb/ArtoOksanen_GRB090912_2455087.38910_.fits\n\nThe AAVSO thanks the Curry Foundation for its support of the\nAAVSO International High Energy Network.",
  "circularId": 9907,
  "createdOn": 1252837071000,
  "email": "matthewt@aavso.org",
  "subject": "GRB 090912 optical upper limit",
  "submitter": "AAVSO GRB Network at AAVSO  <matthewt@aavso.org>",
  "eventId": "GRB 090912"
}