COS SMOV Morning Update
11 June 2009
Agenda
• COS FUV HV Turn-on Visits 7 and 8 (of 13)
– Ramp-up status
– Dark and PtNe wavecal lamp exposures
• COS-to-FGS Alignment / Coarse Focus : 11468: Visit 1 of 2
(COS08)
• Upcoming COS SMOV Timeline
.
COS FUV HV Turn-on:
Visit 7 and 8 (of 13) HVLOW to third ramp level
•
On Wed 10 June:
– HV successfully taken from HVLOW (-4069 v) to third intermediate ramp-up
level (A/B HV command levels of 166/163 (188V below HVNOM))
– The data collected during the latest FUV detector HV ramp step was nominal;
All diagnostics remain nominal on both segments
• HV current histograms dumped immediately after the HV ramp (visit 7) and just before the
drop back to HVLOW (visit 8) were nominal; QE grid and rear field talk backs all nominal; no
indications of transient behavior;
• PHDs nominal : photon PHD modal gain increases and FWHM as percent of mean decreases as expected.
– Background rates consistent with previous visits.
• There is a significant modal gain contribution to the background PHD
– Expected to be exponential fall as function of gain.
– Likely source of near modal gain peak is ion gauge.
– If so, backgrounds will drop significantly when gauge is off.
– Wavecal spectra normal: position of spectra fell directly on top of one of
previous visits.
Visit
HV A/B
Bkg A/B
Lamp A/B
PHD A/B
•
3
154/151
19.4/29.6
198.9/619.1
7.0/7.0
5
160/157
17.7/26.1
200.5/611.6
9.3/9.6
7
166/163
18.5/26.9
199.5/614.0
11.5/12.1
TV06
178/175
9.50/17.6
245/724
14/14
Recommend ops request to clear event flag 3, continue with next step in
FUV HV turn-on procedure (on Fri afternoon)
COS FUV HV Turn-on:
Visit 7: full active area PHDs for background exposure
COS FUV HV Turn-on:
Visit 7: full active area PHDs for wavecal exposure
COS-to-FGS Alignment / Coarse Focus :
Visit 1 (of 2)
• Visit executed over night; completed at 7:57 AM EDT
• Status:
– Downlink for fastrack at 9:30 A.M. EDT this morning; CCS telemetry
observed for much of first 5x5 search pattern
– First 5x5 pattern completed nominally; appears to be external light in at last
one tile of pattern
– Optical Alignment team will begin working on data immediately to determine
pointing offset from nominal blind-pointing and focus mechanism updates to
facilitate continuing focus measurement in visit 1 of 11469
• Following analysis, prepare ops request to update to execute
during 11468 visit 2 on Sat morning;
– will update nominal focus mechanism position;
– uplink position offset for use in future visits with same target and GS;
– possibly update additional mechanism positions
Upcoming COS SMOV Timeline
• Day 162: Thurs 11 June
– 11468 visit 1 of 2 (COS08) COS-to-FGS Alignment / Coarse Focus
• “First-Light” : First observation of an external source with COS
(astrometric F type MS star in cluster NGC-188)
• After blind pointing perform 5x5 POS-TARG search pattern via
MIRRORA images at each point; perform pattern for 3 separate coarsely
separated focus settings (-500, 0, +500)
• Perform ACQ/SEARCH and ACQ/IMAGE tests; perform several
TAGFLASH image mode exposures to determine WCA-to-PSA offsets
for future target acquisition parameter updates
• 1146801 162:03:47:17 - 162:11:57:32
• Analysis of imagery will yield pointing update and may yield focus and
mechanism updates all to be uplinked via real-time contact in visit 2 on
Sat 13 June
Upcoming COS SMOV Timeline
• Day 163: Fri 12 June
– 11356 visit 9 of 13 (COS23) FUV HV Turn-on
• ramp from HVLOW to fourth specified ramp value (seg A/B: -5105??/5057?? v), dump DCE, wave , dark exp
• OPS request required: clear NSSC-1 COS event flag 3 set in 1135608
• 1135609 163:17:25:00 - 163:18:02:28
• No event flag set; leave SI at HV level for 4 hours; then execute 1135609
– Contingency OPS request in place to place FUV in INHIBIT if anomaly
• science data
– 11356 visit 10 of 13 (COS23) FUV HV Turn-on
• After 4-hour wait at first specified ramp value, dump DCE RAM, return
to HVLOW
• sets event flag 3
• 1135610 163:21:40:00 - 163:21:41:36
• clear NSSC-1 COS event flag 3 prior to visit 11
Upcoming COS SMOV Timeline
• Day 164: Sat 13 June
– 11468 visit 2 of 2 (COS08) COS-to-FGS Alignment / Coarse Focus
• s/c visit to facilitate real-time uplink of offset pointing information to be
used in as OFFSET 11469A in 1146901 (which follows within ~1 hour);
uplink nominal focus position update based on analysis of 1146801;
possibly uplink additional mechanism position updates based on analysis
of 1146801
• 1146802 164:12:54:25 - 164:13:17:58
– 11469 visit 1 of 12 (COS09) COS Fine Optical Alignment
• Use same astrometric target as 11468 visit 1
• Apply uplinked offset (from 1146802) to blind pointing position to
approximately center target in PSA; use same orient and same astrometric
guide stars (GS) as 1146801; no target acquisition
• Obtain MIRRORA images at each of 15 moderately-spaced focus
positions (from +525 to -525 in steps of 75 units)
• 1146901 164:14:00:24 - 164:15:02:44
• After analysis of imagery uplink refined nominal focus value, offset
pointing , and possible mechanism position updates via real-time contact
in 11469 visit 2 on Mon