Download SPACE TELESCOPE SCIENCE INSTITUTE Bright Object Alerts

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SPACE TELESCOPE SCIENCE INSTITUTE
15 March 2005
Denise Taylor
Bright Object Alerts
Which instruments do we check?
1. WFPC2: No health and safety issues with bright objects, but alerts will be
generated if the target is brighter than v=0mag (Sirius).
2. NICMOS: Same as WFPC2.
3. FGS: Bright objects may saturate the PMTs, leaving an after-image that could
endanger an upcoming guide star acquisition. Clearing the alerts usually
requires the use of FOV, and are handled by Denise or Tricia.
4. ACS: CCDs (WFC, HRC) have no health and safety issues with bright
objects. Bright object alerts on MAMA (SBC) must be cleared by the Instrument Scientist (IS).
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SPACE TELESCOPE SCIENCE INSTITUTE
15 March 2005
Denise Taylor
Procedures for Dealing With Bright Object Alerts
Alerts are generated by NGSS when guide stars are found for an obset. If there are no
guide stars, no alerts will be generated, even if there are bright objects! Observations
that are designed to execute with gyro guiding have a special guide star request file
used only for finding bright objects (only in 3-gyro operations).
The Toolbox Flight-Ready button is tied to the bright object alerts. A visit can not be
set to Flight-Ready unless outstanding bright object alerts have been waived.
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SPACE TELESCOPE SCIENCE INSTITUTE
15 March 2005
Denise Taylor
Generating Bright Object Alert Waivers
ACS/SBC MAMA
Bright object alerts are reviewed by the Instrument Scientist during the normal proposal review. The submission of an approved review triggers flags in ASSIST to
change the status of an alert from Pending to Waived. New alerts are generated every
time NGSS is run. All alerts are stored in ASSIST until manually purged, and are
time-stamped. The newest alerts for an obset must have a status of Waived in order to
execute the observation.
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SPACE TELESCOPE SCIENCE INSTITUTE
15 March 2005
Denise Taylor
When the newest alerts are still Pending and you need to make a visit flight-ready,
what do you do?
♦ Ask the IS for a review if there isn’t one.
♦ Ask the IS for a new review if there were changes to the visit or target that
would affect the guide star coverage or bright object protections.
♦ Use the UPDATE tool to reset the IS review date if there were no changes to
the visit or target which would affect the guide star coverage or bright object
protections. This will trigger the status to change to Waived.
FGS
Waivers are generated manually by the PCs. The IS review does NOT trigger a bright
object waiver for FGS alerts. The FGS IS does not have access to FOV to investigate
these alerts. See Denise or Tricia if FGS bright object alerts need investigating.
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SPACE TELESCOPE SCIENCE INSTITUTE
15 March 2005
Denise Taylor
Changes Which Affect Guide Star Coverage or Bright Object Protections
1. Any changes to the target: Coordinates, equinox, epoch, proper motion, flux,
plate id.
2. Changes to instrument configuration: Aperture, spectral element, exposure
time.
3. Pointing changes: ORIENT, POS TARG, SAME POS AS.
4. Timing changes if target is variable: BETWEEN, AFTER, BEFORE,
PHASE.