From: elt@astro.Princeton.EDU

Submitted: Fri, 1 Jun 2001 15:13:26 -0400 (EDT)

Message number: 507 (previous: 506, next: 508 up: Index)

See attached.

The possibility of making optical follow-up observations of GRB's within
*minutes* of the gamma-ray event is clearly an enormous scientific 
opportunity and one which the APO 3.5m is particularly well suited to
exploit due to our rapid instrument change capability.

The program JH08 (PI Karl Glazebrook, will be considered
to be in operation as of tonight (6/1/01).  If a GRB alert occurs and passes
all of the filters which have been put in place by the science team, the
on-duty OS (who is a co-investigator) will take over the telescope, slew to
the reported position of the GRB, attempt to identify a bright optical
transient and, if successful take a series of Echelle spectra (after rotating
the tertiary as needed).  Fairly elaborate procedures have been worked out
and tested as best possible in simulated "dry runs".

Obviously, the science program in progress at the time of such an event
will be interupted with virtually no warning.  Equally obviously, this
unexpected interuption will be disconcerting to the observer(s) who is
(are) pre-empted.  Please understand that there is no other way to obtain
this perhaps very important type of data.

If you are the observer using the telescope when a GRB interupt occurs, an
effort will be made to let you close the shutter and read out the current
exposure before the telescope is moved.  Please be ready to do so promptly
and WITHOUT DISCUSSION OR DEBATE when informed by the on-duty OS.  (There
will be no time for talking about it since the GRB optical counterpart is
expected to be fading on a timescale of minutes or even seconds.)  Please
then stand-by until the OS has an opportunity to let you know what to expect
next.  It is possible that no bright optical counterpart will be located and
that the telescope will therefore soon be returned to your program; it is
also possible that the rest of your time for that night will be lost to
ongoing afterglow observations.

Any program which loses time to such a no warning GRB interupt will be
compensated with future time taken either from JHU's allocation or, in
some initial cases, from DD time.  Eventually, if this program is successful,
a detailed policy for this compensation will be adopted, but for the initial
instances, each will be worked out by the Director in consultation with the
affected PI and the JH08 PI on a case-by-case basis.  This will be done later,
not during the night of the interupt.

If you have comments or concerns about this project or procedure, please 
describe them in email sent to the JH08 PI (Karl Glazebrook,
with copies to your institutional Users Cmte member, Bruce Gillespie and me.

Ed Turner


------- Start of forwarded message -------
From: GCN Circulars <>
Subject: HETE Fully-Automated GCN Notices
Date: Thu, 31 May 2001 19:27:37 -0400 (EDT)
Affiliation: NASA-GSFC LHEA
Project:     GCN (GRB Coordinates Network), Circular Service
Phone:       301-286-3106 (S.Barthelmy's office,  -1684 fax)
Content-Type: text/plain; charset=US-ASCII

NUMBER:  1064
SUBJECT: HETE Fully-Automated GCN Notices
DATE:    01/05/31 23:09:24 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <>

During the past two weeks, the final testing of HETE-GCN rapid data 
interfaces was successfully completed.  Beginning today, HETE 
localization releases are fully automatic.  HETE Notices will now be 
promptly distributed through the GCN system.  The HETE positions
are calculated on-board, down-linked through the 12 Secondary ground
stations, forwarded to the HETE Ops computer at MIT, and then forwarded
to GCN for distribution to those GCN sites that have elected to receive
the GCN/HETE Notices (Alert, Update, Final, and/or GroundAnalysis subtypes).
This is the full automated process; there are no humans in the loop,
i.e. the minimum possible delay time.  The time delays range
from 10 sec to 30 sec for the Alert and Update Notices (Updates are
the first notice subtype that has position information.)

A detailed description of the HETE Notices is contained in:
and for the socket sites, the packets are defined in:

It should be stressed that because this is the fully automated, 
"hands off" processing procedure, there will inevitably be non-GRB 
triggers included in those sent to the ground and distributed.
In fact, during the June-July period, when the Galactic Bulge region
is passing through the HETE field-of-view, the majority of the triggers 
will be non-GRBs.  While this is probably not a problem for the 
automated instrument GCN sites, those sites that involve human effort 
and/or consumables must understand that many of the HETE Notices will 
be non-GRBs (eg x-ray bursters, soft gamma repeaters, flaring 
galactic sources, etc).

In general, there will also be follow-up GCN Circulars disseminated 
for HETE burst events which prove to be confirmed GRBs.  These 
follow-up Circulars will be based on detailed telemetry data which 
becomes available on the ground 1-2 orbits after the burst, so such 
HETE Circulars will lag the HETE Notices by a few hours.

All those sites who have requested the HETE Notices to be enabled 
need do nothing.  They will receive them.  If sites wish to change 
their configuration, then please send a request.
------- End of forwarded message -------

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