Bent Gregorian Technical Observing with IRTC: UT 2009 September 23

Observer: D.Thompson, MPedani (@LBT), DMiller (Tucson)
Telescope Operator: David Gonzalez-Huerta
SW support: NCushing, MDeLaPena, TLeibold (Tucson)


  • Clear, but cold front came through with 3 arcsec seeing
  • Presets with proper motions works correctly: SW:B30t1 passed
  • updatePointingOrigin for RADEC offsets: SW:B31t2 failed
    • Patch to PCS appears to have fixed it!
  • Presets even far off AGw_Y axis work
  • A dice5 on IRTC shows rms positioning errors of 50.6 mas in X and 32.7 mas in Y
  • Collected some blank-sky WFS data to investigate improving centroiding

  • LUCIFER will be mounted for tomorrow night

  • Torsten:
    • There appears to be many corrupt guide images displayed in GUI
    • Will need to work on exposure time scaling algorithm
    • Recommend removing adjustable flip parameters for LFBG (after discussion)
    • FWHM_X and FWHM_Y are identical in guide image headers
  • Michele
    • Recommend removing adjustable flips for LFBG (after discussion)
  • Norm
    • Would be interesting to derive offset times during dice5 between 04:32:51 and 05:45:38


  • Verify PCS flips for LUCIFER and IRTC are identical, appropriate
    • 20090917 JMH: in PCSInstrument.conf for LUCFIER: set LEFTXYFLIP = false false
    • 20090917 JMH: in PCSInstrument.conf for IRTC: already LEFTXYFLIP = false false
    • PCS restarted as part of B32B installation
  • Verify GCS xflip set as appropriate
    • 20090917 JMH: in AIP_L.cfg (for B32A)
      • WFS_pupil_shift_x = -1.0
      • pointingCorr_flip_x = -1.0
      • guidingCorr_flip_x = -1.0
    • 20090917 JMH: in AIP_IRTC_L.cfg (for B32A)
      • WFS_pupil_shift_x = -1.0
      • pointingCorr_flip_x = -1.0
      • guidingCorr_flip_x = -1.0
  • Verify AGw transform pcsmx set appropriately
    • 20090917 JMH: in oacontrol.conf pcsmx = -1
    • TLeibold restarted oacserver
  • Verify AGw transform updated with new rotation matrix
    • JStorm provided new file: /etc/oacontrol/oacontrol.conf.20090918rev1
    • TL restarted oacontrol.
  • Review GCS exposure time scaling algorithm
    • Done by DThompson and TLeibold
    • Threshold for scaling guider images reduced from 500 to 100
    • Behavior of wfs needs to be tested with 120s exposures
  • Make additional Stone fields for astrometric calibrations
    • StoneAagw and LongOff5A included in
    • LongOff5A script prepared


00:47 IRTC powered up, interface started OK, appears to be cooling chip.
01:15 Verified we can take images through iraf interface and they appear in /Repository
01:30 IRTC TEC down to 247K.

01:30 Sunset. Tair=6.3C RH=38% DewPt=-7C Wind=3.6m/s max. Some layered haze very low on horizon, but otherwise no clouds.

01:36 Tried starting TCSGUI from LBTO account on lbtmu41 but this failed. Norm will add LBTO to the "lbt" group so this is possible for the time being. For future use, it would be a good idea to allow observers (from LBTO, INAF, LBTB, OSURC, and AZ) to launch readonly versions of the GCS, PCS, and IIF GUIs if they want to (to see guiding and telescope status).

01:43 did "su telescope" on lbtmu42 and launched IIF and GCS GUIs.
01:54 authorize as LUCIFER in IIF. IRTC registered as LUCIFER.
01:56 Mirror ventilation in fault, not starting. DGH to investigate. Reset "pressure blower" but it faulted again, cleared in SW.

02:01 pointto M5_1469 in TRACK mode. Failed because M2 would go outside SW limits. Paul is resetting this for B32B.

02:0 pointto M5_1469 in TRACK mode to adjust pointing and initial focus.

pointto BS9170 gs=0 ACTIVE to collimate

pointto BS9170 gs=40 ACTIVE (r=40 arcsec)

Wiki does not like ^X, darn it. To summarize what was lost over the last hour - we were guiding on a R=15.2 guide star in 1.8 arcsec seeing with only ~23 counts above background (2.1 second exposure). In good seeing we should be able to guide on 18mag but a longer exposure may be necessary. Transform appears to work, will test later. The mirror is 3 degrees warmer than outside, so we have some local seeing.

3:04 Seeing is fluctuating between 1.6 and 2.2 arcsec.

03:10 pointto Vega in TRACK mode. Will compare coords that PCS puts into syslog vs. pmpt2. entry for Vega 18:36:56.336 +38:47:01.29 +.2868 +.287 2000.0
proper motions are in sec/yr and asec/yr.

PCS finds:
pointto = 18:36:56.503300 +38:47:04.082000
pmpt2 = 18:36:56.466416197 +38:47:04.081540926
So RAs agree to 0.43 arcsec, DECs agree to 0.5 mas.

03:50 pointto Barnards (Barnard's Star) in TRACK mode
pointto sends: 17:57:47.9786 +04:43:16.807
PCS uses: 17:57:47.9786 +04:43:16.807
for pmpt2: 17:57:47.9803 +04:43:16.804

Presets with proper motions test [SW:B30t1]: passed

03:56 pointto WT10_219 to re-point. IE now -67. CA now -55.
04:01 pointto BS9183 gs=48 in ACTIVE mode to collimate.
takepic 2.0 (image #040744)
offset 5.0 5.0 type="REL" coord="DETXY"
takepic 2.0 (image #040917)
zerobase DETXY side="left"

04:11 pointto BS9183 gs=48 in ACTIVE mode to collimate. (20:52:47.3000 6:40:05.000)
takepic 2.0 (image #041315)
offset 5.0 5.0 type="REL" coord="RADEC"
takepic 2.0 (image #041429)
zerobase RADEC side="left"

RADEC offsets "absorb" [SW:B31t2] test: failed
When the updatePointingOrigin command is issued, the RA and DEC coords plus offsets in DD do what they are supposed to do, but guiding still fails. Michele will note the MJD when I send an updatePointingOrigin command to look for a discontinuity in the trajectories.

04:25 pointto BS9183 gs=48 ACTIVE (PA=30.82 on AGw_Y axis)

04:25 pointto BS9183 gs=48 ACTIVE PA=75
offset 0.0 -2.0 type="REL" coord="DETXY" to recenter
zerobase DETXY side="left"

04:32 dice5 off1=7.0 off2=7.0 coord="DETXY" nloop=10 (04:32:51 at start, 05:45:38)
Telescope AZ 198, EL 62 at start of sequence.
043313/cube0001 at start, 054428/cube0050 at end
During this sequence we had a moister and colder mass of air come over. As of 05:27 Tair=2.9 RH=60% Wind gusting between 4 and 15 m/s. Tmirror=5.4, seeing is about 2.5 arcsec.

dice5 results:
de-rotate the pattern by -1.1 degrees and de-shift by 7.0 arcsec gives 50.6 mas rms in X and 32.7 mas rms in Y for the 49 points collected. This is consistent with the results from May and June. The individual sets of 9-10 points at each position in the dice5 pattern show similar numbers to the ensemble average. Guider images taken during the dice5 script (guiderimages 1123 to 2241) show and rms in X of and in Y of pixels ( mas).

Note that the R=14.1 guide star gave 550 counts peak in the 2.1s guide exposures in 1.1 arcsec FWHM seeing. This means that a 17.3 mag star should guide with 30 counts peak. It also means that the exposure time scaling algorithm still needs tuning as this source should have guided with 1 second integrations.

We are also regularly getting partial/corrupt frames from the guider, displayed on the GUI, are these correlated with the offsets?

05:47 pointto BS9183 gs=0 ACTIVE. Seeing very bad, can't guide.

05:51 pointto WT10_206 gs=0 ACQUIRE. IE=-76 CA=-79. Seeing still 2.5 arcsec.

Stop and restart PCS so Michele can delete the trajectory file to force a new one to start.

06:09 pointto StoneAagw gs=0 ACQUIRE offset 5.0 5.0 type="REL" coord="RADEC"
zerobase RADEC side="left"

Stop PCS so Michele can copy the file elsewhere. Patch applied to PCS and restarted.

06:19 pointto StoneAagw gs=0 ACQUIRE offset -5.0 -5.0 type="REL" coord="RADEC"
zerobase RADEC side="left"

Seems to work! Also checked coordinate behavior in DD, also looks good.

Doug takes over to get long exposures of blank sky

pointto StoneAagw gs=0 ACQUIRE PAM- PA=0, then adjust IE to move star off wfs. Doug to take "blank sky" images with wfs at 30, 60, 90, and 120s exposures to investigate better pedestal removal and/or flatfielding on wfs data to improve centroiding algorithm over current center-of-weight method.

Data in /Repository/AGW_Data/090923w

06:54 Finally get readWFSCam executable to work as telescope on lbtmu43

06:54 wfsc000001.fits (1 sec exposure)

06:56 wfsc000002.fits (30 sec exposure)

06:58 wfsc000003.fits (60 sec exposure) Never returned.

07:07 Stopped and started GCS

07:10 Still no wfsc image. Guide image OK. Stopped and Started AGw to cycle power on AZCam

07:18 Now get wfsc image. Tried 60 sec again, and no return. I realized that I was using short integers math and result was for exp>32768 ms I was requesting a negative exposure time. I fixed my IDL routine and now work.

07:33 wfsc000004.fits (60 sec exposure)

07:33 wfsc000005.fits (90 sec exposure)

07:33 wfsc000006.fits (120 sec exposure)

07:49 IE now -71. CA now -59.
pointto StoneAagw gs=0 ACTIVE mode to recollimate. Seeing still jumping around, 2.5-3.0 arcsec. Tair=1.6 Tmirror=3.0

07:56 Slew to zenith to restart DIMM electronics.

08:09 pointto StoneAagw gs=0 ACTIVE. Seeing variable from 2.3 to 3.2 arcsec FWHM

09:00 Continuing poor seeing obviates remaining tests (field aberrations, pointing, guide to 18mag). Tair=1.6, Tmirror=2.4. Temps and humidity have been relatively stable for the last two hours.
JMH: Note that tempertures of glass and telescope steel decreased from 9.5 degC to 1.5 degC during this night. See the attached plot. Because of the cold front, the rate of temperature change was 3-4 times larger than on a typical night. So it isn't surprising that the seeing was poor.

10:15 poinrto StoneAagw TRACK mode to check pointing...drifted
10:20 pointto WT10_210 TRACK. IE now -70, CA now -67.

10:29 pointto BS9108 gs=0
stop guiding and WFS, turn over to Doug.

WFSC background

10:30 Dave pointed to a star and then send an offset

10:35 wfsc 07, exp=30, no dd because and error in IDL. Fixed

10:37 wfcs 08, exp= 30

wfsc image exp Probe x,y
08 30 0,612.
09 60 0,612.
10 120 0,612.
11 90 0,612.
12 30 120,600
13 60 120,600
14 90 120,600
15 120 120,600
16 30 -120,600
17 60 -120,600
18 90 -120,600
19 120 -120,600
20 30 -80,540
21 60 -80,540
22 90 -80,540
23 120 -80,540
24 30 -80,540
25 60 -80,540
26 90 -80,540
27 120 -80,540
28 30 0,490
29 60 0,490
30 90 0,490
31 120 0,490


11:50 pointo bs9116 gs=30 PA=0 => xy = -5.303, 513.331

12:05 offset 5 0 detxy => x,y = -2.32, 513.32

12:07 offset 0 5 detxy => x,y = -5.358, 510.341

12:08 offset 5 0 radec => x,y = -8.331, 510.351 (detxy 0 5 still in place)

12:11 offset 0 5 radec => x,y = -5.266, 513.335

12:14 offset 0 0 radec => x,y = -5.333, 510.342

12:18 offset 0 0 detxy => x,y = -5.303,513.337

12:20 offset 0 0 detxy => x,y = -5.27, 513.337

12:25 pointto bs9116 gs = 30, PA=0, ACQUIRE =>x,y -5

12:26 offset 10 0 detxy => move right on Guide (off chip)

12:29 offset 10 10 detxy => move down on Guide

12:30 offset 10 -10 radec => move up on Guider

12:33 offset -10 -2 radec => move left on Guider (to hotspot)

12:37 pointto M5_0258 TRACK PA=0

12:38 offset 10 0 detxy => move left on IRTC

12:39 offset 0 10 detxy => move down on IRTC

12:40 offset 10 0 radec => move right on IRTC

12:41 offset 0 10 radec => move up on IRTC

12:42 Closed

Observing Plan


Presets with proper motions [SW:B30t1]

  • "pointto" to source with high proper motions
  • "pmpt2" to same source
  • Check that the coordinates used in PCS are the same.
  • Can be done closed-dome

RADEC offsets "absorb" [SW:B31t2]

  • Preset to any source, ACTIVE mode
  • Do RADEC REL offset to move off
  • "zerobase" to absorb the offsets
    • Should remain guiding
    • RADEC coordinates in DD should now be the new (offset) position
    • Offsets in DD should be zero
  • Repeat with DETXY offsets (sanity check that nothing has changed)

Other SW tests
  • B30t2 verify tracking recovers from IDLE mode on rotator (do as LUCIFER?)
  • B28t1 new workstation astro SW all set up? (hushiraf)


Dither accuracy (one dice5, one longoff?)
  • Execute one dice5 with ~10 arcsec offsets, x10 repeats, any source
  • Execute one longoff pattern
    • Stone L is 3 hr W at 7:00pm (LongOff5L)
    • Stone M is 1hr W at 7:00pm (LongOff5M, PA=0)
    • Stone A transits at midnight (LongOff5A gs=13, PA=170.8)

guide rms
  • Use the dice5 or long offset data to determine rms
  • Do we need data to 20 minutes?

B22t11 verify achieved coords on offsets

Field aberration measurements (DMiller)

Lower priority:
  • Long exposure images with wfs on blank sky

  • guide to 18th mag (adjust autoscale algorithm?)
  • wfs on 18th mag (adjust autoscale algorithm?)

Pointing Model?
  • Not strictly necessary, but useful to compare with new LUCIFER pm
  • Use ARC method to measure AGw/Rotator center on IRTC
  • 24 points are sufficient

  • Test communication with TCS (should be doable off-telescope?)
  • Re-orient on sky (N accurately along columns at PA=0)
  • Re-calibrate AGw transform (short or long set?) [SW:B30t3]
  • Re-measure AGw/Rotator center with ARC method
  • Check DETXY offsets in X - everything flipped as needed? [SW:B32t1]
  • Make new collimation model, implement (optional if it looks good)
  • Make new pointing model, implement (if coll model good)
  • Test re-calibrated Instrument-AGw alignment
  • Discuss with Marcus dropping images onto archive
  • Discuss with team astronomical applications for "IDLE" mode on rotator

-- DavidThompson - 15 Sep 2009
I Attachment Action Size Date Who Comment
daq.20090923.gifgif daq.20090923.gif manage 50 K 23 Sep 2009 - 23:45 JohnHill Plot of Telescope and Mirror Temperatures
Topic revision: r19 - 27 Sep 2009, JohnHill
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