UIST Engineering

	Instrument Apertures and Foci

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

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 - 20 Aug 2004)
All apertures to be measured on QA night, please
Mode	to 20040622	to 20040820	current
Imaging 0.12	-5.77,-1.07	-6.37,+2.39	-6.83,-3.29
Imaging 0.06	-2.59,+0.75	-3.31,+4.31	-3.56,-1.24
Spectroscopy	+6.65,-0.75	+6.73,+5.03	+6.37,-0.69
IFU	+0.69,-1.07	+0.83,+4.67	+0.67,-1.29
Polarimetry	+24.43,+1.08	+24.69,+6.21	+24.37,+0.41

Notes:
1. Use the same aperture for imaging-polarimetry and spectro-polarimetry.
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) + 31.2, Imaging(0.12arcsec) + 3.7

Location on array
Use these numbers for imaging acquisition AND aperture measurements
(Last update of this table - 4 April '03)
Apertures highlighted in red to be measured on QA night, please
Mode	Location on array, (x,y)
Spectroscopy, 1 pix slit	506.4	590
Spectroscopy, 2 pix slit	505.2	590
Spectroscopy, 4 pix slit	502.2	590
Spectroscopy, 5 pix slit	501.5	590
Spectroscopy, 7 pix slit	507.7	590
X-disp Spectros, 3 pix slit	503.5	541
X-disp Spectros, 5 pix slit	503.4	541
X-disp Spectros, 7 pix slit	504.0	541
Spec-Pol, 2 pix slit	510.6	740^*
Spect-Pol, 5 pix slit	511.6	740^*
IFU	499	540
Imaging, 1024x1024 (0.12")	480	480
Imaging, 1024x1024 (0.06")	480	480
Imaging, 512x512	224	224
Imaging Polarimetry	511	740 ^*
Notes: ^* The aperture for imaging-pol and spec-pol is the same; this should be measured WITHOUT the prism in the beam. This aperture puts the star; (1) in the centre of the top aperture in the imaging-pol-mask, or (2) in the centre of the top slit in the 5-pixel spec-pol-mask. The E-beam image/spectrum of the star will then be on pixel 510,823; the o-beam data will be on 510,655 [for H-band]).

**Additional offsets during source acquisition**
(Last update of this table - 4 April '03)
Grism	Filter used	Additional offset by TSS at telescope
IJ	J-spec	right 0.67 arcsec
Short_K	B2	left 0.05 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).

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 - 22 June '04)
Mode	Focus, mm
Imaging, 0.12" (& Spec)	0.70
Imaging, 0.06"JHK	0.95
Imaging, 0.06"LM	0.70
IFU	1.0
Pol	0.74
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:
20040622 | 20040522 | 20040402
20031220 | 20031124 | 20031003
20030903 | 20030731 | 20030424
20030403 | 20030131 | 20030106

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Instrument Apertures and Foci