Instrument Apertures and Foci

ENG History:

• March 03: UIST off scope to replace grisms and filters
• December 03: UIST off scope (cryogenic/vacuum problems) from Dec '03 until 2 April '04.
• August 04: Heavy engineering (rewiring) and computer upgrades in control room, though UIST remained cold and on telescope.
• August 04: UIST warmed up when chiller failed. Back to nominal operating temp after being down for two days (31 Aug/1 Sep).
• Oct-Nov 04: UIST off during WFCAM commissioning. Back on mid-Dec (wasn't opened).
• February 05: Grism wheel 2 failure
• June 05: UIST back on after telescope after WFCAM run. But bad connection to DAQ 2 giving 4-bad/4-good columns in the top-left quadrant. Also, problems with filter wheel 2 stuck, and focus a bit flakey towards end of 2 month run on scope.
• January 06: UIST back on after 6 months off for WFCAM. New slits with spacers installed for IJ and JH, plus prototype coronographic mask. Slits don't seem to help though, and coron pol mask orientated 90 deg w.r.t. normal pol imaging mask (so dispersion will be along aperture).
• August 06: UIST back on after summer WFCAM block. UIST removed for possible shipping to ATC (didn't happen); spacers adjusted on new 2pix and 4pix slits for IJ.JH spec (slightly better); new coronographic mask installed. OT updated to accomodate posn angles with "imaging" (for coron only), and to make the new slits available.

NOTE: Details on how to measure the UIST apertures and Focii are given on the main QA-night web page.

Notes:
1. POLARIMETRY: Using the same aperture for imaging-polarimetry and spectro-polarimetry; the former is measured and entered in the system. This means that with spec-pol acquisition the star in imaging mode will always be slightly off (posn angles of more than -90 will make things progressively worse!); pick-off at the scope will fix this, moving the target onto the slit..
2. CORONOGRAPH: Again, using the same aperture for pol and non-pol. Aperture should measured (with all the other apertures), using the non-pol reference pixel lsited below.
2. The arcsec values are simply the mm values x -1.524
3. The first value is E-W, the second N-S, so in the rotated UIST frame the first value is along the slit (up and down, or in Y in pixels - see below)
4.The difference between apertures should be fixed (so strictly speaking we only need to measure two apertures - imaging at the two camera plate scales). Approximate relative offsets are:

 - Spectroscopy = Imaging(0.12arcsec) + 13.2, Imaging(0.12arcsec) + 2.6 
 - IFU          = Imaging(0.12arcsec) +  7.5, Imaging(0.12arcsec) + 2.0
 - Polarimetry  = Imaging(0.12arcsec) +   21, Imaging(0.12arcsec) + 1.5 
 - Coronograph  = Imaging(0.12arcsec) -   20, Imaging(0.12arcsec) + 32.5 

The acquisition pixels and additional offsets listed above are read by the telescope from: /jac_sw/itsroot/src/oracda_new/uist/uocs.cfg (file at the summit, not in Hilo - updated/maintained by Russell). This file also includes the plate scale,

UIST Focii

The plot below shows fine-focus measurements taken on QA nights. Note that not all focii are measured on a given day (so some values are missing). The dates marked "UIST off scope" indicate when the instrument was physically taken off the telescope for a period of time. Thus, after one of these periods values might be expected to change...

 

Pink - 0.12 imaging focii; Blue - Spectroscopy focii; Yellow - 0.06JHK focii; Light Blue - 0.06LM focii; Purple - IFU focii; Brown - Pol focii.
NOTE: 0.12" imaging and spectroscopy focii should be the same.

Values being used at the telescope (i.e. NOT necessarily the last value measured) are given in the table below

Earlier apertures and focii are available on previous versions of this web page. The date corresponds to when an update was made:
20060808 20060210
20050628
20040622 | 20040522 | 20040402
20031220 | 20031124 | 20031003 | 20030903 | 20030731 | 20030424 | 20030403 | 20030131 | 20030106