Right Front Bent Gregorian Focal Station Commissioning Plan with Adaptive Secondary

Prerequisites DONE

  • Initial guess at pointing model - will use same as IRTC @ LFBG (John - done)
  • Initial guess at RIGHTZEROPOINT. This will be near zero, as AGW2 should be mounted differently than AGW3. (John+Doug - done)
  • Initial guess at primary mirror collimation model. This will be LBC plus Andrew's offsets at zenith. (John - done)
  • Initial guess at AGw2 transformation in oacontrol.conf (Jesper/Thomas - done)
    • Note new location: /lbt/oacontrol/etc/oacontrol.conf
  • Right GCS configuration files in AO3 (Torsten - done)
  • Align Gregorian adaptive secondary and tertiary to Right Front Bent Gregorian rotator axis (Andrew - done twice)
    • Use Laser tracker input to update collimation LUTs for M1, M2, M3. (John+Andrew - done)
  • Day time commissioning of AGW2. Able to position AGw on-axis, wfs apert. coincident w/rotator center (Jesper - done)
  • AGW2 installed on telescope @ RFBG according to RfbgMountAgw (done)
  • IRTC installed on telescope @ RFBG according to RfbgMountAgw (done)
  • Flattened adaptive secondary (Armando and friends - done 16-MAR-2010)
    • Shell cover removed and hexapod power on. (Marco - done 19-MAR-2010)

TCS Software Off-Sky and On-Sky Verification Tests DONE

Test new features in Build AO3 at LFBG DONE (completed off-sky, and LFBG,RFBG on-sky; missing LBC on-sky)

March 19th, Day 1, 9 hours, 00:00 UT to 09:00 UT (10 hours)
  • Test Build AO3 - See detailed instructions in SWTestReports and see detailed new features in SWReleaseNotes2010.
  • Perform all tests that require no starlight and all test that require starlight. These tests require a moving telescope and all hardware.
  • Activate & Test AO3 using all Telescope hardware, and LBC and LFBG AGw#3.
  • This is done initially with AGW3 at LFBG so that we can separate software issues from hardware and configuration issues at RFBG.
  • Continued software testing at RFBG will be included in later steps below.

March 20, Day 2, 3 hours, 02:00 UT to 05:00 UT (3 hours as needed if Day 1 tests were not completed in full)
  • Test Build AO3 - See detailed instructions in SWTestReports and see detailed new features in SWReleaseNotes2010.
  • Perform all tests that require no starlight and all test that require starlight. These tests require a moving telescope and all hardware.
  • Activate & Test AO3 using all Telescope hardware, and LBC and LFBG AGw#3.
  • Finish uncompleted starlight required tests from prior night.
  • Continued software testing at RFBG will be included in later steps below.

Initial Pointing and Collimation of RFBG

Initial Pointing with IRTC DONE

  • Switch PCS to be Right-sided on TCSGUI.
  • Determine initial pointing model zero points
    • Reset AZ and EL encoders
    • Start PCS pointing logging (and verify that it works right-sided)
    • Point to very bright source, e.g.:
      • Vega at 18 36 56.3364 +38 47 01.291
      • Pollux at 07 45 18.9503 +28 01 34.315
      • Regulus at 10 08 22.3107 +11 58 01.945
      • Arcturus at 14 15 39.6720 +19 10 56.677 (watch out for high proper motion)
      • Note: these 4 stars are now in the default catalog used by "pointto".
    • takepic an image with IRTC, or put IRTC into continuous readout mode
    • collimate (by eye) to correct focus and coma. [Andrew says move only M2 RX/RY for initial collimation.]
    • Offset dAZ = CA, dEL = IE to center star on detector
    • Repeat at low elevation to adjust IA
    • Add zero point offsets to initial pointing model in /home/telescope/TCS/Configuration/PCS (will need to give it a new name).
    • Load updated pointing model
    • Test that right-sided preset now gets you to that star
    • Pointing errors should now be dominated by tube flexure (mostly elevation).
    • Note star position on MAT camera data (helps with future pointing)

Build Initial Collimation Model with IRTC (Only done for 45-80 degrees so far)

  • Adjust initial collimation at high elevation DONE
    • Point to an M5 star at high elevation (> 80 degrees)
    • Adjust collimation with M2 RX/RY as above
    • Adjust IE/CA again if needed.
  • Establish initial (ON-AXIS) collimation lookup table
    • Point to bright stars at a range of elevations
    • MAT may be useful to help point, else use spiral search ptspiral
    • Adjust Zglobal to get an extrafocal image.
    • Send Z7/Z8 in arbitrator "primary" mode for manual collimation.
    • Implement initial collimation lookup table using CollimationModel instructions.

  • What if M1 does not have the range to achieve collimation? (we are slightly close to the M1 Y limit at mid-elevations)
    • Offset both M1 and M2 as needed to being them back on range. See CollimationLimits although this procedure may require more optical insight than those instructions provide.

  • What if adaptive M2 does not have the range to achieve collimation?
    • Call Andrew

Need also to Map Low-order Shell Zernikes as a function of elevation. DONE (Done for Z6 which dominates)

Initial Rotator Zeropoint with IRTC DONE

  • PCS/MCSPU: Check Position Angle and Rotator Motion with IRTC
    • Old plan: point to clusters with known asterisms or double stars at several parallactic angles
    • New plan: It was hard to find asterisms, so we made the first cut by offsetting the telescope in known directions.
      • Preset in TRACK mode and center the star with IE/CA.
      • Offset the telescope and observe which way the star moves on IRTC.
      • Be certain that you are sending your offsets in RADEC space and not DETXY space.
    • take IRTC images/cubes with takeseq at several position angles (Remember that IRTC is rotated 90-degrees from nominal PA=0. This makes this procedure difficult, so the suggestion is to rough align with the Guider [below] and then come back for a refinement with IRTC.)
    • verify sign (parity) and zeropoint of the position angle for IRTC
    • Adjust RIGHTZEROPOINT in PCSInstrument.conf
    • verify direction of the rotator

GCSR Functionality Tests DONE

  • GCSR (These are interwoven with AGw activities below so nothing to do here.)
    • acquire images (off-sky)
    • move stages (off-sky)
    • guide telescope
    • offset star onto wfs
    • acquire wfs images
    • process wfs images and send Zernike corrections for active optics

AGw Commissioning for AGW2

AGw Guider Camera Initial Calibration DONE

  • Acquire on-axis star on Guider camera
    • Point telescope so star is on the center of rotation on IRTC (Preset in ACQUIRE mode)
    • Verify that AGw guider probe is at nominal on-axis position
    • If star not present, use ptspiral routine to search for star
    • Once star is found then slowly walk star/guide probe to IRTC on-axis position (Do we really want to do this? It is really done as part of the following section.)
    • Note the new nominal probe position

Measure Rotator Center and establish the position of the optical axis DONE

  • Determine rotator center in AGw space
    • Start up the AGW unit
    • Move AGw to nominal on axis position
    • point to a cluster of stars
    • take two images 180deg rotation apart and determine rotcen
    • alternately - rotate the rotator while taking a 70 sec exposure
    • Reposition AGw stage to align with center (Jesper)
    • Repeat as needed to position rotator center on WFS aperture
    • Note stage positions, we will need them again!

Measure Fixed Angular Offset DONE

This was subsumed into the initial measurement of the transformation.

  • Determine fixed angular offset for rotator based on guider. This is only a sanity check of what we did with IRTC previously.
    • Point to wide double stars with known PAs
    • Determine PA offset for that camera
  • New plan: It was hard to find asterisms, so we made the first cut by offsetting the telescope in known directions.
    • Preset in ACQUIRE mode with on-axis guide star
    • Center the star with IE/CA.
    • Offset the telescope and observe which way the star moves on Guider.
      • Be certain that you are sending your offsets in RADEC space and not DETXY space.
    • take Guider images at several position angles.
    • verify sign (parity) and zeropoint of the position angle for Guider
    • Adjust RIGHTZEROPOINT in PCSInstrument.conf

Guiding Tests DONE

  • Test closed loop guiding on-axis with GCS
    • Did the acquisition offset center the star in the guide box
    • Is the guiding stable to perturbations, or does the star drift off in the wrong direction?
  • Sort out required parameter changes to make guiding stable.
  • Guide off-axis to verify rotator rates

AGw WFS Camera Initial Calibration

Warning: AGW2 WFS camera is upside down compared to AGW3 and AGW4. This is because of clearance issues for the new flexible cables.

Find Hotspot on Guider to put star in center of WFSC pinhole DONE
  • Send a GUIDE preset
  • Acquire star on WFSC
    • Option A
      • Place star on nominal "Center of WFSC Pin Hole" position (guiding is doing this)
      • If no S-H spots then move guide probe small amounts in spiral pattern till spots found
      • Move guide probe in +x,-x, and +y,-y till spots are vignetted
    • Option B
      • Stop guiding
      • Move telescope around with IE/CA to search for spots
    • Note guider (x,y) image position of "Center of WFSC Pin Hole" and guide probe position of "Center of WFSC Pin Hole". Adjust the configuration file as needed.

Initial Check of Active Optics Corrections DONE
  • Option A - GCSR
    • Send preset to on-axis star in ACTIVE mode with sending corrections to PSF blocked
    • Calculate Zernike aberrations, send them manually with PSF starting with focus, then coma, then astigmatism, trefoil
    • Calibrate orientation of Z's, single mode, and adjust rotation of zernikes as needed.
  • Option B - IDL DONE
  • Use Z9, Z10 to refine the Doug's angle offset
  • Verify that both IDL and GCS agree on the angles and flips.

Initial Closing of Active Optics Loop DONE
  • Option A - GCSR
    • Send preset to on-axis star in ACTIVE mode with sending corrections to PSF enabled
    • Calculate Zernike aberrations, send them manually with PSF starting with focus, then coma, then astigmatism, trefoil
  • Option B - IDL DONE
  • Verify that both IDL and GCS agree on the convergence

Off-axis Active Optics DONE (done for IDL; done for GCSR)
  • Verify the pupil positioning for off-axis stars is going in the right direction.
    • First on the Y-axis
    • Then over the whole field
  • Verify the range of pupil motion available on the WFS camera.
  • Verify active optics convergence at extreme field positions
  • Calculate Zernike aberrations, send them manually with PSF starting with focus, then coma, then astigmatism, trefoil
  • Verify that both IDL and GCS agree on the angles and flips.

Focus the Guider relative to IRTC (Is approximately correct, took data on 20100403)

This procedure needs good seeing. 0.6 arcsec or better in order to achieve sufficient precision.

  • This is the fast procedure which does NOT run Active Optics while stepping the secondary mirror.
    • Preset in ACTIVE mode
    • Allow a few minutes for active optics to collimate.
    • Record the nominal focus offset and the present off-axis position.
    • Press StopWFS button on GCSGUI
    • cl < home$focus_seq.cl which will take a series of IRTC cubes while offsetting focus.
  • Repeat the procedure several times until you've converged on a value for the focus offset.

  • The slow procedure would make steps in the nominal probe focus offsets and run active optics at each step. This turns out to be vulnerable to changes in the seeing
over the tens of minutes that the procedure.

Check X-Y position of probe relative to focus position DONE (Done - 20100331)

This procedure does not care so much about the seeing.

See BGTechProcedures for the procedure.

Initial Calibration of AGw coordinate transform DONE

See document 481g221c "AGW Coordinate Transformations and their Calibration".

Preset to one of the Stone fields close to the meridian listed in StarCharts. Only these Stone fields with good astrometry and proper motions are useful.

Use the IRAF transtar script described in JohnSpecial. Doug should also have a new IDL command to test.

Note: ImportantParameters for RFBG in LBTtools

Be sure that you are taking IRTC data in H-band. If you want to use J-band, it will be necessary to change RIGHTWAVELENGTH in the appropriate place in /home/telescope/TCS/Configuration/PCS/PCSInstruments.conf.

Please record the current value of LEFTZEROPOINT/RIGHTZEROPOINT.

Collecting Transform Data

The initial transform needs about 25 stars. Seeing should be no worse than 0.8 arcsec.

See the detailed instructions in TransformationData

Collect Data for Refinement of AGw coordinate transform DONE

As above, but we want ~50 stars on a single field over a range of position angles.

Initial adjusting Field Aberrations with M2 collimation table DONE

See the detailed setup in AOwithIDL, and see the more general description in FieldAberrationMeasurementDetails .

Give Simone et al. the 1-week warning for W-on-sky Tests DONE

At this point, the AGW and related software should be able to reliably able to position a star at a consistent location in GUIDE mode or ACTIVE mode. This means that we should give the W-people the indication that they are able to do W-unit testing on sky in ~1 week (or sooner as they prefer). Simone seems to be thinking(16-March-2010) that they may be able to do this test remotely from Arcetri.

Sent the invitation on 23-March-2010. With window to schedule the test between 25-March and 5-April. Simone prefers the second halves of 31-March and 1-April MST which are 1 April UT and 2 April UT.

AGw On-Sky Commissioning

Calibrate WFS corrections

    • Take Intra/Extra-focal Image Pairs adjusting focus with M2
      • optimize size of the extrafocal pupils
      • take multi-extension image cubes for averaging the atmosphere (40 sec)
      • verify sign and rotation of EF corrections by applying known wavefront distortions to M1

Photometric Performance of Guider

Astrometric Performance of Guider

Flexure During Guiding

See section 6.5 of Jesper's AGW Commissioning Plan. Measure flexure as AGw rotates crossing meridian at several elevations.

Refining Field Aberrations with M1/M2 collimation table

This procedure needs good seeing.

Measure two deliberately induced offset vectors (4-6 hours) DONE
Apply the corrections DONE
Measure the final result (3 hours) DONE (1st iteration completed 20100404, 2nd iteration 20100405)
Check Field Aberrations at Two Elevations (6 hours)

Tertiary Mirror Tests DONE

Check M3 position repeatability DONE

(from Paolo)

  • Home the system
  • Point the system to the AGW2 focal station (RFBG)
  • Verify alignment (Andrew ?? Optically with AGW ??)
  • Move the M3 mirror (only) to a completely different attitude in tip/tilt (so that we can approach to the limits with the mirror cell sloped differently)
  • Repeat the full homing procedure for mirror (only, not selector)
  • Re-point the RFBG (AGW2) and check the alignment in the same way.

  • Repeat the procedure homing the selector rather than the mirror.

Verify angular offsets on sky DONE

Need to think about which coordinate system to make these tests in. At minimum we should verify the expected scale of motion.

M3 range of motion DONE

See Paul Grenz. It was suggested to do this while pointing at a star (not guiding), so the alignment can be recovered if something goes wrong. Could be done in bad seeing conditions. 20100406: Paul reports that he did this test previously in closed-dome, so there is nothing additional to do on-sky.

Further Improvements

Recheck Rotator Center on AGw

  • (Optional, sanity check) Re-determine rotator center
    • Position AGw at the rotator center as above
    • point to a cluster of stars
    • take two images 180deg rotaton apart
    • Determine rotcen as mean of average coords of matched sources
    • Reposition AGw stage
    • Repeat as needed to position rotator center on WFS aperture
    • Note stage positions, we will need this again!

Improve Pointing Model (50 stars collected)

  • Improve pointing model - precise instructions for the pointing model are found in PointingModel (bullets below are only a summary).
    • Turn on mount pointing logging on PCS
    • Point to ~100 W&T pointing stars well-distributed across sky
    • spiral search to find if needed (hopefully not!)
    • position accurately on the WFS/rotcen
    • take an image, note time reasonably accurately (+/- 5s)
    • match source RA/DEC and mount pointing for tpoint
    • run tpoint
    • install improved pointing model
    • Hope that this gets us below ~5" rms (what we see at other focal stations)

Improve Collimation Model

  • Improve collimation model - precise instructions for the collimation model are found in CollimationModel (bullets below are only a summary).
    • Point to bright stars at a range of elevations
    • MAT may be useful to help point, else use spiral search ptspiral
    • Take Intra/Extra-focal Image Pairs adjusting focus with M2
      • optimize size of the extrafocal pupils
      • test multi-extension image cubes for averaging the atmosphere
      • verify sign and rotation of EF corrections by applying known wavefront distortions to M1
    • Collimate (using EF) [Move only M1 for initial collimation.]
    • Implement initial collimation lookup table using mkcoll.pro

Improve AGw Probe Transformation

Cross-Calibrate Zernike Coefficients between M1 and M2 (Done for Z4-Z11)

This can be done in 1 arcsec seeing.

* Apply low-order Zernikes to M2 (with AdSec interface), and measure the results with IDL or GCS. Z4-Z22 with both signs.

Sometime in the future we will want to do the converse, and use bigW to measure Zernikes applied to M1.

Other Activities

IRTC Camera On-Sky Verification

IRTC2 has already been tested at LFBG and LDG focal stations, so these are mostly sanity checks

  • Determine rotator center in IRTC space
    • point to a cluster of stars
    • collimate
    • take two IRTC images 180deg rotation apart and determine rotcen
    • you must change the rotator angle with an offset command and not with a preset which can also shift the telescope

  • IRTC Optical Tests (zoom scales, field aberrations, etc)

  • IRTC Detector Performance
    • 50 x 1 sec dark data (dome closed)
    • 50 x 1 sec blank sky data (3 dither positions)
    • Estimate point source and pupil SNR for stars of a known magnitude (choose a star cluster)

Pretty Pictures with IRTC

The Bologna guys and others would appreciate seeing some nice pictures taken with IRTC. The core of M3 or the center of M82 come to mind as possible targets. They will become extremely popular once the adaptive loop has been closed.

Adjust IAA for IRTC orientation

We've never really used the PCS IAA term, but it was designed to solve the problem where IRTC is rotatated compared to the nominal LUCIFER/AGw orientation. This is the situation we have here with how IRTC2 is mounted on AGW2. So the thought is to test this term on sky if we have the opportunity. Will it be needed for MODS?

From the 20100321 tranformation data, Jesper finds that the IRTC images have to be rotated 90-degrees CCW to match North-up at PA=0. Presently IRTC has North to the right at PA=0.

The tricky part of this test is that the preset needs to account for a different position of the guide star.

Completion of the DX Hardpoint Checkout

IRTC can be used insted of LBC-Red to complete the DX Hardpoint checkout. See Engineering.NewHardpointCellCheckout.

This document has a heritage in GregorianCommissioning which was used for LFBG and LDG. JMH has rearranged the order of some activities to match practical reality.

-- JohnHill - 02 Mar 2010
Topic revision: r27 - 07 Sep 2010, JohnHill
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