UIST: Engineering: Checkout

UIST: Engineering: Checkout

Below are listed checks for when UIST is put back onto the telescope (after a period of engineering or WFCAM block). Can all be done on Ohi , logged on as observer

1. Daywork

There are MSBs for most of these tests in U/EC/5 (under Permanent Daytime tests).

  • Datum mechanisms – followed by the Readnoise and Long Dark (dark current) calibration observations.
  • Check all modes In U/EC/5 run “UIST Daytime Tests – all modes”. This will take darks, flats, arcs and observations in imaging (thermal and non-thermal), spectroscopy and IFU. All wheels (including focus and image rotator) will be exercised. The “sub” version has just very basic checks [Maren – good for you, perhaps?] NB: To get these to come up in the QT, you may have to disable constraints.
  • Polarimetry The “UIST Daytime Tests – IRPOL” programme will exercise IRPOL, in imaging and spec-pol modes. BEWARE – is IRPOL bagged? Moving it may not be a good idea!
  • Reading waveforms: Thermal and non-thermal/full and sub-arrays. Can these be loaded without error (should be checked when you run the above sequences).
  • New Grism or filter? If so, then need to establish internal focus and step value.
    • For FOCUS: view arc lamp through grism, appropriate blocking filter and the 2-pix slit. Can run from engineering epics screens (see below). Load and run “do_focus_run” exec, or set focii manually in uistCCS_control.dl and simply run “observe” exec (can edit/create own execs in /jac_sw/itsroot/install/engineering/data/). Note: range of travel for focus is 0.5-5mm. Can analyse data with this script: calib_focus.prg.
    • For STEPS: View BB lamp “continuum spectrum” through the grism, appropriate blocking filter and the 4-pix slit. Check spectrum runs along rows. Again, tweak steps from engineering epics screens. Can analyse data with this script: calib_grism.prg.
  • New Slit, mask or aperture? Check that the slits are orientated along columns. Can use this script: calib_slit.prg
  • Imaging Acquisition: Location of slits on array. Numbers on the instrument-apertures-and-foci page used for imaging-acquisition. Done from eng. epics windows by looking through slit and a filter (do PK50 and B2 [used with IJH and HK grisms) – check the same!) at the BB lamp with 2sec expos. Do this if the slit wheel has been removed (or if hasn’t been done for a while).

2. Nighttime at the summit

There are MSBs for most of these tests in U/EC/5 (under Permanent Nighttime tests).

  • Port and tilt – the sequence for this is in u/ec/1. Can do this in day/twilight with the dome closed and the lights on. Either keep the mirror covers closed and minimise the signal as per https://about.ifa.hawaii.edu/ukirt/instruments/ukirt-fast-track-imager/ufti-engineering/ircam-and-ufti-realignment-procedure-on-telescope/ or put UIST in pupil imaging mode with the covers open. (link to page of sample pupil images…)
  • Foci and apertures – there are sequences in ec/1, and the guidelines in the QA notes.
  • Angle of array on sky – use a simple 0.12″/pixel imaging MSB, with offsets set to 0:0, -50:0, +50:0 and then 0:0, 0:-50, 0:50.
  • Imaging acquisition I – load a normal standard star MSB. Acquire the star in the normal way, continue past “Break for Movie” and set object. However, at second break, rather than continue, run Movie again and nudge star left and right by 0.5 arcsec. Is the slit peaked up on the star? Repeat for 2pix, 4pix and 5pix slits with HK grism.
  • Imaging acquisition II – as above, but repeat with different grisms. Check in particular the longer-wavelength grisms (short-K, long-K, etc.) where an additional offset is applied by UPICK (as listed in uocs.cfg and on UIST-eng “apertures and focii” web page).
  • Sliding along slit – use a simple point-source MSB, but with a long slide. Are the beams balanced? If not, stop the MSB and slide up and down the slit by hand; work out left/right offset needed in each beam. Repeat for at least two slits. (Related to centre of rotation – see below)
  • Dichroic vignetting – probably only necessary if a new dichroic has been installed.
  • Center of rotation, flexure? – these are both described in the QA Guide (half-way down the page). The centre of rotation probably affects how well stars are slid up and down the slit. The flexture model affect accuracy of apertures, though is probably less essential.
  • New filter/grism – check spectral resolution, imaging acquisition on a star with a standard flat/arc/star MSB. Does the imaging acquisition need an additional offset (is acquisition and imaging done through different filters)?

3. Array – Running UIST from the engineering interface

UIST can be run with UCLIENT. Described in detail on the WFCAM page on the staff wiki.

4. CCS – Using the Individual Mechanisms control windows.

uistMenu gives the full list of UIST windows that are potentially useful for engineering; from this menu, the small CCS Engineering DM screen (uistCCS_eng.dl) allows you to open screens for individual mechanisms; filters, grisms, focus, etc. The slit wheel mechanism is shown here. From these windows you can move wheels a fixed number of steps, e.g.:

   - Power (top left) set to ON
   - Select slit from Menu pull-down
   - Click Start (notice the step changing bottom-left)
   - Datum Force to TRUE 
   - Click Start again (this time, the wheel will go to the
     slit via the datum switch)

Note that the Read Back Value (RBV) is relative, i.e. it sets to zero from where the wheel currently is, then steps until finds it datum. Sets to zero again at the datum switch; now it knows where it is, and can find grisms or filter by moving the appropriate number of steps given in .data file.

To move a wheel manually, a few steps say, change the DVAL (demand value – bottom left corner) by a few hundred steps and hit return. The RBV should update to the new value.