UIST Engineering

	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).

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

**Apertures (in arcseconds)**
(Last update of this table - 11 February '06)
All apertures to be measured on QA night, please
Mode	to 20040622	to 20040820	to 20050628	to 20060210	current
Imaging 0.12	-5.77,-1.07	-6.37,+2.39	-6.83,-3.29	-7.43, -1.59	-3.03, -2.49
Imaging 0.06	-2.59,+0.75	-3.31,+4.31	-3.56,-1.24	-4.28, 0.02	+0.32, -0.61
Spectroscopy	+6.65,-0.75	+6.73,+5.03	+6.37,-0.69	5.77, 1.11	+10.22, +0.30
IFU	+0.69,-1.07	+0.83,+4.67	+0.67,-1.29	0.07, 0.41	+3.65, +2.11
Polarimetry	+24.43,+1.08	+24.69,+6.21	+24.37,+0.41	23.77, 2.11	+17.93, -1.11
Coronograph	-	-	-	-	+5.20,+23.87

Notes:
1. 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 2 arcsecs off; pick-off at the scope will fix this, moving the target onto the slit..
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

Reference Pixel on array
Use these numbers for imaging acquisition AND aperture measurements
(Last updated/checked - 17 March '06)
Apertures highlighted in red to be measured on QA night, please
Mode	Reference Pixel on array, (x,y)
Spectroscopy, 1 pix slit	508.0	590
Spectroscopy, 2 pix slit	506.5	590
Spectroscopy, 4 pix slit	504.0	590
Spectroscopy, 5 pix slit	503.5	590
Spectroscopy, 7 pix slit	506.0	590
Spectroscopy, 2 pix slit with spacer	506.0	590
Spectroscopy, 4 pix slit with spacer	503.5	590
Coronographic occultor (wire)	689.0	550.5
Spec-Pol, 2 pix slit	512.5	735^*
Spect-Pol, 5 pix slit	512.5	735^*
IFU	499	540
Imaging, 1024x1024 (0.12")	480	480
Imaging, 1024x1024 (0.06")	480	480
Imaging, 512x512	224	224
Imaging Polarimetry	490	735 ^*
Notes: ^* The reference pixel used for imaging-pol and spec-pol are NO LONGER THE SAME. However, we use the same APERTURE for both imaging and spec-pol. The aperture is defined by moving a star (without the wollaston in the beam) onto the imaging pol reference pixel. When slewing to targets, with imaging pol this aperture should put the star just to the left of the central column on the array; with spec-pol this posn doesn't coincide with the slit. However, its only 2 arcsec from the slit, and UPICK will then move the star onto the slit. NB. With the prism in the beam, the dispersed E-beam image/spectrum of the star should be close to y-axis pixel 818; the o-beam data will be on 640 [for H-band]).

**Additional offsets during source acquisition**
(Last update/check - 11 February '06)
Grism	Filter used	Additional offset by TSS at telescope
IJ	J-spec	right 0.60 arcsec
JH	J-spec	right 0.60 arcsec
Short_K	B2	right 0.2 arcsec
Long_K	B2	left 0.90 arcsec
KL	B2	left 0.90 arcsec
Short_L	3.4cont	left 0.10 arcsec
Long_L	BrA	right 0.17 arcsec
M	BrA	left 0.15 arcsec
PLEASE NOTE: UPICK automatically applies the above offsets. TSSs do not have to adjust the source position after imaging acquisition in the thermal (this is why upick puts the star on a slightly different pixel than is listed earlier on this page).

The acquisition pixels and additional offsets listed above are read by the telescope from: /jac_sw/itsroot/src/oracda_wfcam/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

**Telescope FF Currently In Use**
(Last update of this table - 11 February '06)
Mode	Focus, mm
Imaging, 0.12" (& Spec)	0.80
Imaging, 0.06"JHK	1.0
Imaging, 0.06"LM	0.65
IFU	1.1
Pol	0.70
Notes: The 0.12" imaging and spectroscopy foci should be about the same. The 0.06"JHK focus should be MORE than the 0.12" focus by about 0.19mm. The 0.06"LM focus should be LESS than the 0.12" focus by about 0.03mm. The IFU focus should be MORE than the 0.12" focus by about 0.21mm The Pol focus should be MORE than the 0.12" focus by about 0.03mm

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

Previous: Grism Wheels | Up: UIST Engineering | Next: UIST Engineering

Instrument Apertures and Foci