- Press Release
- Nov 26, 2022
NASA Hubble Space Telescope Daily Report #4860
HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science
DAILY REPORT #4860
PERIOD COVERED: 5am June 4 – 5am June 5, 2009 (DOY 155/0900z-156/0900z)
COS NUV Initial On-Orbit Turn-On and Recovery after Anomalous Shutdown
This proposal is designed for the initial turn-on of the COS NUV MAMA detector. The same procedure may later be used to recover the detector after an anomalous shutdown. Anomalous shutdowns can occur as a result of bright object violations which trigger the Bright Scene Detection or Software Global Monitor. Anomalous shutdowns can also occur as a result of MAMA hardware problems. The Initial MAMA turn-on consists of three tests: a signal processing electronics check; a slow high voltage ramp-up to an intermediate voltage; and a slow high voltage ramp-up to the full operating voltage. During each of the two high voltage ramp-ups, diagnostics are performed during a dark time-tag exposure. The turn-on is followed by a MAMA Fold Analysis Test. The complete sequence is contained in visits 1 through 4. If a second execution is required during cycle 17, visits 5 through 8 will be run and another proposal prepared for possible future occurrences.
Supports Activities COS-04 and COS-07
COS FUV Initial On-Orbit Turn-On
This proposal specifies the procedure for SMOV initial HV turn-on and ramp-up of the COS FUV detector. (The FUV will have been commanded to its Operate state to support execution of proposal 11353.) The procedure is detailed in the Observing Description, but in summary, the following is done: The initial transition from FUV Operate to HVLow is broken into two parts, with a gap of 4 hours between turning on the HV and ramping to the HVLow (SAA) voltage. This will be followed by 5 cycles of HV ramp-up and return to HVLow. Cycles will ramp up to successively higher (magnitude) voltage, with the fifth cycle going to the nominal operating values. There will be a gap of at least 4 hours between cycles. All HV ramp-up will be done at 10 sec per HV “step”. The step rate and cycle voltage values (for Segments A and B) must be patched in FSW in each cycle prior to the HV ramp commanding. Memory monitors will be set on the patched memory locations. Immediately after any HV commanding, and 4 hours after ramp-up commanding, the DCE memory will be dumped. Immediately after HV ramp-up commanding higher than HVLow, short DARK & WAVE exposures will be obtained. Visits 01 and 02, and all the subsequent even numbered visits (the ones 4 hours after HV ramp-ups), end with NSSC-1 COS event flag 3 being set. If the flag remains set, subsequent FUV commanding will be skipped. Thus, Operations Requests must be in place to clear the flag prior to those subsequent visits. Real-time monitoring of the telemetry will be used to guide the decisions whether or not to clear the flag. The final visit (13) provides a scheduled final opportunity to clear flag 3, and if the flag is cleared, initiates nominal FUV HV commanding and requests a DARK exposure.
An Astrometric Calibration of Population II Distance Indicators
In 2002 HST produced a highly precise parallax for RR Lyrae. That measurement resulted in an absolute magnitude, M(V)= 0.61+/-0.11, a useful result, judged by the over ten refereed citations each year since. It is, however, unsatisfactory to have the direct, parallax-based, distance scale of Population II variables based on a single star. We propose, therefore, to obtain the parallaxes of four additional RR Lyrae stars and two Population II Cepheids, or W Vir stars. The Population II Cepheids lie with the RR Lyrae stars on a common K-band Period-Luminosity relation. Using these parallaxes to inform that relationship, we anticipate a zero-point error of 0.04 magnitude. This result should greatly strengthen confidence in the Population II distance scale and increase our understanding of RR Lyrae star and Pop II Cepheid astrophysics.
CCD Dark and Bias Monitor for SMOV4/Cycle 17 Activity STIS-07
Monitor the darks for the STIS CCD. Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns.
STIS-11 External Focus Check
This proposal will check the STIS focus and alignment using two tests. In the first test, ACQ/PEAK exposures with the G230LB are used to dither the 0.1×0.09 aperture across a point source to sample the PSF. Relative counts at different wavelengths give a measure of PSF shape at different wavelengths. Full frame comparison exposures will also taken using the 0.1X0.09 and 52X2 apertures, and the relative aperture throughputs will give an estimate of the image quality at the STIS aperture plane. In the second test, the target is imaged onto the STIS CCD using the narrow-band F28x50OII filter. Comparison with previous OII images will be done to estimate the state of the focus.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
COMPLETED OPS REQUEST:
18475-0 – Clear COS Event Flag 2 after NUV initial turn on Part 3 completes @ 155/1342z
18467-1 – Clear STIS Event Flag 2 (MAMA1 Checkout Part 3) @ 155/1356z
18489-0 – Disable Sun/Aperture test @ 156/0117z
COMPLETED OPS NOTES: (None)
FGS GSAcq 5 5
FGS REAcq 3 3
OBAD with Maneuver 5 5
The COS NUV fold test was successfully completed at 155/18:43z. The FUV HV was enabled at 155/21:06z, but not ramped. The FUV detector is scheduled to be ramped to HVlow at 156/16:55:20z