The infrared system must be started in the order listed below.

If you have not yet done so, start up  the telescope control software from the telescope console. You need to configure the telescope for Cassegrain operation by issuing the following commands or including their equivalents in your startup procedure:

CONFIGURE SECONDARY IR_CASSEGRAIN 
CONFIGURE INSTRUMENT_IDENT CASPIR 
CONFIGURE FOCAL_STATION CASSEGRAIN 
CONFIGURE EFFECTIVE_WAVELENGTH 2000.0
CONFIGURE GUIDE_WAVELENGTH 700.0
CONFIGURE ROTATOR_CW_LIMIT +110
CONFIGURE ROTATOR_CCW_LIMIT -270

ROTATOR/REFERENCE POSITION_ANGLE
ROTATOR  180

Now enable control of the telescope from MOPRA by typing:

ENLIST IR

into the telescope console terminal.

If you plan to use the Tip-Tilt secondary mirror enable telescope control from the Tip-Tilt system by typing:

ENLIST TT

into the telescope console terminal.

If you have previously saved a telescope configuration file (as described below) load it now and set the telescope aperture definition by typing:

CFILE/LOAD TEMP.CFILE
APERTURE A

To start the infrared instrument control software on MOPRA, first log  on to the MOPRA workstation as user INFRARED (no password required so type a carriage return). This places you in the CASPIR data directory  DATADISK:[INFRARED].

It is not normally necessary to down-load  the LSI-11/23 software unless you are starting the system for the first time or recovering from a power failure. Refer to the Users Guide if you have to do this.

Start up  the infrared control software by typing:

IR_STARTUP

Answer ``N'' to the question about down-loading the LSI software - you should have already done that. Starting the system takes quite a while because it has many subprocesses to spawn. Be patient. When it has finished you will have a Status Display  window and two image display windows (the Run Display  and the Idle Display ) on the workstation screen, and the Status Display will be showing the status of the DECnet links to the LSI-11/23. Wait until `CASPIR : Relinquishing ownership' is printed in the lower part of the Status Display before proceeding.

You should leave the infrared system running for the duration of your run. All that is then required at the beginning of a night is to create a new data sub-directory (IR_DATA:) and reset the run number by typing:

STARTNEWNIGHT

Type:

_CASPIR

to bring up the CASPIR Status Display window and define the abbreviated control commands listed in the command procedure in IR_CASPIR:CASPIR.COM (see the Software Commands for the display ). This selects CASPIR as the active dewar and starts data taking in idle mode.

You should now be seeing an image of the array in the Idle Display window.

The CASPIR dewar uses a closed-cycle helium refrigerator  to cool the camera and detector array - it does not need liquid nitrogen. Check that the array and camera body have reached their operating temperatures  by looking for ``Temperature Out-Of-Range'' error reports in the CASPIR Status Display. To be doubly sure type:

TEMPERATURE/DISPLAY

The camera temperature should be about 60 K and the array temperature should be 32 K with a tolerance of 0.1 K.

Check that the IMB is configured correctly by typing:

IMB/DISPLAY

The dichroic mirror turret should be at position `A' and the IMB X-Y stage at its `home' position (X = 0.0 mm, Y = 0.0 mm).

Now return to the CASPIR display by typing:

CASPIR/DISPLAY

Configure the instrument for the type of measurement you want by typing one of the following:

FAST     - Direct imaging with the fast camera (0.5"/pixel).
SLOW     - Direct imaging with the slow camera (0.25"/pixel).
JGRISM   - Long slit J grism.
HGRISM   - Long slit H grism.
KGRISM   - Long slit K grism.
IJGRISM  - Short slit cross-dispersed IJ grism.
JHGRISM  - Short slit cross-dispersed JH grism.
HKGRISM  - Short slit cross-dispersed HK grism.
GRIDPOL  - Polarimetry with the wire grid.
PRISMPOL - Polarimetry with the Wollaston prism.
CORONA   - Coronograph imaging (0.5"/pixel).

If you are using one of the imaging modes, select the desired filter by typing f followed by a filter name from the following list:

J,          H,          K,          KP,         KN,         M,        
HELIUM,     PGAMMA,     PBETA,      CONT1.6,    FEII,       AAOFEII,    
H2O,        H2_1_0,     BRGAMMA,    CONT2.22,   H2_2_1,     CO,         
ICE,        DUST3.28,   DUST3.4,    CONT3.6,    CONT4.0,    BRALPHA

For example:

F KN

Set the idle method, idle time, and idle cycles to typical values (for imaging in the JHK region) and repeats to one by typing:

IM 2
IT 0.3
IC 10
REP 1

Other values may be better suited to the particular measurement you are making. Refer to the Software Commands for instrument control to see how to set these parameters.

If you are using the Tip-Tilt system, log into MISTY as yourself or ``user23'' (password in the CCD temperature book), start OpenWindows, and start the Tip-Tilt software by typing:

tiptilt &

After the initialization has completed, go from idle mode to acquire mode by clicking on the ``operate'' button. Enable Tip-Tilt control and IMB X-Y stage motions from CASPIR DO files and in NOD mode by typing:

CASPIR/TIPTILT/STAGE

into the CASPIR command terminal.

If you are not using the Tip-Tilt system, disable Tip-Tilt control and IMB X-Y stage motions from CASPIR DO files by typing:

CASPIR/NOTIPTILT

into the CASPIR command terminal.

• Make sure the IMB dust slide is open. This must be done manually using the small grey handle on the IMB mounting flange adjacent to where CASPIR mounts on the IMB. The open and closed positions are clearly marked on the IMB mounting flange.

Now that the instrument is fully configured you are ready to acquire an object. Slew the telescope to a bright star at a zenith distance of at least 20 degrees and perform the following alignments:

• The dewar should be tipped to point at the secondary mirror. Check the dewar alignment  by driving the telescope out of focus and checking that the image of the primary mirror in the Idle Display is unvignetted. This can be done using either the normal direct imaging cold stop in position 2 of the Utility Wheel, or the alignment mask in position 1 of the Utility Wheel (see Table ). Using the former, you see the full primary mirror aperture and must gauge whether the image is circular. Using the latter, you see the image through four small holes located at the periphery of the pupil mask and must gauge whether the four images have equal brightness. Either image display can be zoomed  in by clicking on the window title, moving the cursor onto the image and repeatedly pressing the F2 key (see the Software Commands for the display). Remember to reset the zoom by pressing the F3 key in the image part of the window, and then click on the command input window again to reconnect the keyboard to this window. Normally it will not be necessary to adjust the dewar alignment, but refer to the Users Guide if you are forced to do this.
• Focus  the star in the Idle Display, and center it in the middle of the array. This should also be done with a zoomed image display. Either use the F19 key in the Idle Display window to report the FWHM of the stellar image in pixels, or with the fast camera (0.5'' pixels) use the focussing mask in position 5 of the Utility Wheel (see Table ) to form two images of the star and focus to minimise their separation (i.e., gauge by eye that the two images lie in the same image row). The Figdisp image displays deal only in scaled data, so set the Idle Display greyscale (CASPIR/IZMAX=...) so that the star image you measure is not saturated. Increments of 5 focus numbers usually produce satisfactory results. Activate the title bar cursor position readout using the F6 key in the Idle Display window. Use the cursor to locate the center of the array (pixel [128,128]) and position the star on the cursor.
• Calibrate the telescope coordinates at this position by typing:

  CALIBRATE POINTING

  into the telescope console terminal. The X and Y pointing coefficients should be approximately -30 and -11, respectively.

• The detector array should be aligned with its rows running E-W. Check that the instrument rotator is at the correct position angle by slewing the star in RA to the left and right of the array and noting the row numbers. Alter the nominal instrument rotator position angle by typing, e.g.:

  ROTATOR 179.5

  into the telescope console terminal.

• Calibrate the telescope aperture definition by typing:

  CALIBRATE APERTURE A

  into the telescope console terminal. You are required to drive the telescope to center the star on the central pixel. The telescope computer then rotates the Cassegrain instrument rotator by 120 and you recenter the star at the same pixel position. This locates the array center with respect to the instrument rotator axis, which is the optical axis of the telescope. You are then asked if you wish to define a slit orientation. Answer YES to this question and position the star at each end of the central array row. This is the grism slit direction. The instrument rotator will be returned to the original position at the end of this procedure.

• Recenter the star and calibrate the telescope coordinates again at this position by typing:

  CALIBRATE POINTING

  into the telescope console terminal.

• If you are using the grisms in Nod mode, select the grism slit by typing, e.g.:

  A LSLIT1

  into the CASPIR command terminal. Adjust the Idle Display to see the slit image and note the pixel coordinates of the slit center and the two nod positions you require. Remove the slit by typing:

  A FASTCLR

  and center the star on the slit-center pixel and redefine aperture A to this position by typing:

  APERTURE/HERE A

  into the telescope console terminal. Either move the star to the first nod position manually, or offset the telescope E-W by typing, e.g.:

  OFFSET/SCALE 10 0

  into the telescope console terminal. Define aperture N1 at this position by typing:

  APERTURE/HERE N1

  into the telescope console terminal. Manually move the star or offset the telescope to the second nod position and define aperture N2 at this position in a similar way. Reposition the star at slit-center again by typing:

  APERTURE A

  into the telescope console terminal.

• Drive the IMB X-Y stage to center the star in the Tip-Tilt sensor acquire field using the IMB/XY_INCREMENT command and the keypad arrow keys to move the stage. When the star is centered, exit from this by typing a Q, and zero the X-Y stage relative coordinates at that location by typing:

  IMB/XY_ZERO

  If necessary, focus the Tip-Tilt sensor image using the IMB/FOCUS command and the keypad up/down arrow keys. Exit from this by typing a Q.

• Define the IMB X-Y stage center to the telescope system by typing:

  CALIBRATE STAGE

  into the telescope console terminal. This asks you to define a guide box on the Tip-Tilt image display. To do this, place the cursor on the star and simultaneously press the keyboard ``Shift'' key and click the left mouse button. Respond to the question on the telescope console terminal by pressing ``Return''.

• Record the telescope setup by typing:

  CFILE/SAVE=ALL TEMP.CFILE

You are now ready to record data.

The orientation on the sky in each of the image displays should be as shown in Figure. .
Fig. Orientation on the sky in the image displays (rotator P.A.=180 degrees)

Standard  stars are normally recorded in two frames offset by about 30'' asymmetrically placed about the center of the array. The shortest possible exposure times should be used for standard stars to avoid saturation. These are 0.2 sec in readout method 1, 0.3 sec in readout method 2, and 0.4 sec in readout method 3. The exposure time is set by typing:

CASPIR/TIME=time

The duration of the measurement, and hence signal-to-noise ratio, is defined by the number of coadd cycles which is set by typing:

CASPIR/CYCLES=cycle_count

A measurement is begun by typing:

CASPIR/RUN

Object measurements are normally mosaics  including either separate sky frames or jittered object frames. The observation sequence is defined by entries in a DO  file (see Software Commands ). A DO file for a typical observation can be found in IR_CASPIR:EXAMPLE.DO and has the following form:

!
! Example DO file for acquiring multiple CASPIR data frames.
!
DARK method=2 time=5 cycles=12 repeats=1
RUN ra=+120 dec=+120
RUN ra=   0 dec=+120 
RUN ra=-120 dec=+120
RUN ra=+120 dec=   0
RUN ra=   0 dec=   0
RUN ra=-120 dec=   0
RUN ra=+120 dec=-120
RUN ra=   0 dec=-120
RUN ra=-120 dec=-120
DARK

Do files are read from the directory with logical name IR_DO. On startup, this is set to the default directory DATADISK:[INFRARED]. This can be changed to a private subdirectory by typing, e.g.:

DEFINE/JOB IR_DO DATADISK:[INFRARED.WOOD]

A DO file is executed by typing:

CASPIR/DO=filespec

A given set of coadd cycles can be repeated without moving the telescope by specifying a non-zero REPEATS:

CASPIR/REPEATS=repeat_count

Each coadd cycle is then written to disk as a separate file and displayed in the Run Display.

The data frames are stored as FITS files  in the data directory  with logical name IR_DATA which points to a sub-directory of DATADISK:[INFRARED]. The files are named irnnn.fits where nnn is the run number. These files can also be accessed from MISTY in the directory /data/mopra/... The data values are normalised to the equivalent number of counts obtained in one integration time, i.e., one coadd cycle.

Once you are recording data you may wish to perform on-line processing  on the displayed image.

Subtract a recorded sky frame from the Idle Display image by typing:

CASPIR/ISUBTRACT=filespec

Subtract a recorded sky frame from the Run Display image by typing:

CASPIR/SUBTRACT=filespec

Form a normalised flatfield frame in FITS format off-line using IRAF or FIGARO and divide the Idle Display image by this frame by typing:

CASPIR/IDIVIDE=filespec

Divide the Run Display image by a flatfield frame by typing:

CASPIR/DIVIDE=filespec

To see the mean coadded image of a set of repeats in the Run Display type:

CASPIR/SHOW=MEAN

To return to displaying the current frame in the Run Display type:

CASPIR/SHOW=CURRENT

To remove on-line processing type:

CASPIR/ISUBTRACT=NONE/IDIVIDE=NONE
CASPIR/SUBTRACT=NONE/DIVIDE=NONE

Dark frames  use the exposure time specified by the TIME parameter and the cycles specified by the CYCLES parameter. These can be recorded by typing:

CASPIR/DARK

Bias frames  use the minimum exposure time possible for the selected readout method and the cycles specified by the CYCLES parameter. These can be recorded by typing:

CASPIR/BIAS