It sounds like guiding on-axis is working fine, so if it's possible time-wise and TCS-wise I would like to have some WFSC data collected.

Thus, you will need to test if acquisition of WFSC image is possible while GSC is running. You will need to issue the % wfsc_image request from a directory that contains a Server-Pepsiwfsc.ini file. I would suggest

% cd /Repository/AGW_Data/080424
% wfsc_image

If an image is saved to this directory named wfsc000001.fits then you should be able to acquire the data I need.

WFSC Data

No Guiding:

The first step to determining the orientation of the WFSC relative to the primary is to determine the direction a star on the guide camera moves when the telescope North and West (this you did last night at 4:51 and 5:07 for West, with North up of PosAng = 0. Correct?) If you could record the RotAng or ParAng and:

  • Apply a tip and tilt to the primary and note the direction of the star image on the Guide Camera.
  • Add +5 arcsec to the RX value of the primary position and then a +5 arcsec to the RY value and note the direction of the star image on the Guide Camera.

This will allow me to correlate the zernike directions to RX and RY (I'm sure John knows this correlation). NOTE, the neither the guider nor wfsc image headers contain the Pos/Par/Rot angles. You could take an IRTC image at the same time, which has this info in its head (of course the image will be dark because the guide probe is blocking). BYW, I know the orientation of the WFSC wrt the guider camera from lab tests.

Guiding:

I would like to have several sets of WFSC images with and without specific aberrations applied to the primary to confirm the orientation of the WFSC wrt the primary and determine if there is a scaling between primary wavefront aberrations the those measured by the WFSC.

For a set of WFSC data there are two ways to get the seeing averaged data I need:
  • take a single 20 to 30 second exposure by editing the Server-Pepsiwfsc.ini file in the present directory, or send an exposure flag to wfsc_image (see Acquiring Guider and WFSC images section on the Commissioning Wiki). This will require a dim star. Has guiding been tested on a dim guide star?
  • take 20-one second exposures or 40-0.5 second exposures, etc. I can then average the images to make a seeing averaged image. To acquire multiple images the WFSC, add a parameter to the command wfsc_image (see Acquiring Guider and WFSC images section on the Commissioning Wiki). Currently the wfsc_image routine is set to take 1 milisec exposures, and a full frame. A full frame requires about 2.5 seconds to transfer and save. I will send you parameters for a sub-section of the WFSC image to be transfered and saved, which will run at 3 to 5 Hz. Note: for multiple images, the wfsc_image will create one fits file for each frame (ie for 10 frames you will get wfsc000001.fits to wfsc000010.fits). If you record the first filename, I can use the time the files were crated to determine the files that make a set.

Data Sets: (with a good by-eye collimation; take a few IRTC images=> header info)

  • no aberrations; IRTC frame for info
  • 500 nm z4 (focus)
  • 500 nm z5 (0 astigmatism)
  • 500 nm z6 (45 astigmatism)
  • no aberration; IRTC frame for info
  • 500 nm z7 (x coma)
  • 500 nm z8 (y coma)
  • 500 nm z11 (spherical)
  • no aberration; IRTC frame for info
  • 250 nm z5
  • 500 nm z5
  • no aberration; IRTC frame for info
  • 1000 nm z5
  • 2000 nm z5
  • no aberration; IRTC frame for info
  • guiding turned off, move star off WFSC, take background

Note
you can add a specified amount of aberration on the primary via the PSF:Primary GUI. Click next/prev till correct mode, click clear all (I think that is the name), type in nm value and press return (number changed from red to black), click "Send Modes" (??) and "Apply Modes" (??). Once you have taken data then click the "Clear CDO" (??) button near the top left of the GUI.

IRTC EF Data (similar position in sky so similar Rotator Angle)

No guiding:

EF Data Sets: (with a good by-eye collimation, M2 focus change +- 0.5 mm)

  • no aberrations
  • 500 nm z5 (0 astigmatism)
  • 500 nm z6 (45 astigmatism)
  • 500 nm z7 (x coma)
  • 500 nm z8 (y coma)
  • no aberration
  • 250 nm z5
  • 500 nm z5
  • 1000 nm z5
  • 2000 nm z5
  • no aberration

If time available, but not crucial

  • 500 nm z4 (focus)
  • 500 nm z11 (spherical)
  • no aberration

Off-Axis WFSC

If guiding off axis is working then acquire a 5-die pattern of WFSC images. That is one on-axis WFSC image and then a square pattern of off-axis WFSC images at RA offset = +- 2.5 arcmin and Dec offset = +- 2.5 arcmin.

At each of the five positions collect WFSC data with:
  • IRTC image for position and angle information
  • no aberrations
  • 500 nm z5
  • 500 nm z7
  • no aberrations
  • direction of primary by applying a delta RX and RY and watching which direction the star on the guider moves (or maybe from Guider loop output the direction the guider moved the telescope to compensate)
  • IRTC image for position and angle information

To get to the four off-axis positions start with the on-axis coordinates and then add +-150" to Ra and +- 150" to Dec for guide star position. For example, if the star is at Ra, Dec then:

  • preset (star = Ra,Dec) (guide_star - Ra,Dec or on-axis guide star flag set)
  • preset (star = Ra+150",Dec) (guide_star = Ra,Dec)
  • preset (star = Ra-150",Dec) (guide_star = Ra,Dec)
  • preset (star = Ra,Dec+150") (guide_star = Ra,Dec)
  • preset (star = Ra,Dec-150") (guide_star = Ra,Dec)

Be sure and take an IRTC image at each position for position and angle information.

If you see any changes to this data set acquisition or suggest...

-- DougMiller - 25 Apr 2008
Topic revision: r3 - 26 Apr 2008, DougMiller
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