GCN Circular 1689

J. Wren, W. T. Vestrand, K. Borozdin, S. Brumby, D. Casperson,
M. Galassi, K. McGowan, D. Starr, R. White, and P. Wozniak report:

One of our RAPTOR (RAPid Telescopes for Optical Response) wide-field
telescope arrays responded to the HETE-2 alerts for GRB 021112
(trigger #2448).  That array, located in Los Alamos, New Mexico, is
composed of four Canon 85 mm f1.2 telephoto lenses, which together
image approximately 1300 squares degrees, and a central "fovea"
telescope employing a 400 mm f2.8 Canon telephoto lens that images a
central 16 square degree field. An unfiltered Apogee AP-10 CCD camera
is located at the focal plane of each telescope.

Mosaic imaging of the HETE-2 field-of-view began at 3:29:01 UTC, just
45.4 s after the GRB trigger.  All of the images of the burst location
taken before the GRB position was released place the location of the
burst just 100 pixels from the edge of the imager where vignetting
causes a significant loss of sensitivity.  The image sensitivity was
further reduced by thin cirrus clouds which were apparent in all of
the early images.  No new objects were detected within the HETE-2
error circle after comparison with archival images.  The following
limits were obtained for the initial response images:

Exposure    Time since  Exposure    Limiting   Imager
start time  trigger     duration    Magnitude
(UTC)       (minutes)   (seconds)   (5 sigma)
---------------------------------------------------------------
3:29:56      1.67           5         11.4     wide-field
3:32:49	     4.55          30         11.7     wide-field
4:49:44     81.46          30         14.6     fovea

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