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Observing

2.3m Telescope (CASPIR) DIY manual

Prepared by: John Shobbrook
Amendments by: Peter Wood

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Microsoft Word version of this document is available here

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TELESCOPE AND OBSERVATORY

[OM = 2.3m Observers Manual; CM = CASPIR Manual; Both manuals are in the console room.]

• Check that the MANUAL DUST COVER at the top of the Instrument Mounting Box at the Cassegrain focus is open.
• Whilst at the Cassegrain focus check that the rotator locking pin has been withdrawn.
• Back in the console room, check that General Power and Isolated Power are available (Control Panel).
• Press the TELESCOPE SYSTEMS ON button (Control Panel).
• Press the Break key on the MAIA Control VDU keyboard.
• Type telescope and then enter the password (the password is written in the back of the CCD temperatures log book in the Console Room).
• Enter the Observers Identification/Account Name e.g. WOOD
• At the $ prompt type startup. [For details refer to OM p. 6.2]
• Reply to the list of on-screen prompts. N.B. Rotator = Position Angle, default 179.4°
• Type enlist ir (for CASPIR) and enlist tt (for Tip Tilt) if in use [Refer CM p. 10]
• At TEL$ prompt type display
• At TEL$ type track/file=[peter.observe]stand (no spaces - to load list of standard stars).
• (At TEL$ (if necessary) type switch flat off)
• Open the building shutter (Control Panel / Building Shutter button).
• Switch the ventilation fans on (Control Panel / Mechanical Services).
• When shutter if fully open - Open the primary mirror cover (Control Panel/Primary Mirror Cover button).
• At TEL$ type config windscreen_control vertical_only_tracking

INITIATING CASPIR (AT MOPRA CONSOLE ...) (Mopra uses VMS/DCL commands)

• At Mopra> type startnewnight (Start New Night - as one word with no spaces - this creates a new data directory e.g. DATADISK:[INFRARED.25AUG02]) [CM p.10]
• At Mopra> type set default [INFRARED.WOOD] (alternatively, create your own directory and go there).
• At Mopra> type define/job ir_do datadisk: [INFRARED.WOOD] (Identifies where the observers various DO files are kept) [CM p.14]
• At Mopra> type izauto (sets the Idle Display grey scaling) [CM p.66 5.2.33]
• At Mopra> type zauto (sets the Run Display grey scaling) [CM p.66 5.2.38]
• At Mopra> type im 2 (sets the Idle Readout Method to 2 - Absolute [CM pp. 50-53, 61]
• At Mopra> type iti 0.3 (sets the Idle Time to 0.3 seconds) OR (caspir/itime=0.3)
• At Mopra> type icy 10 (sets the Idle Cycles to 10) OR (caspir/icycles=10)
• At Mopra> type ti 0.3 (sets the Time to 0.3 seconds) OR (caspir/itime=0.3)
• At Mopra> type cy 100 (sets the Cycles to 100) OR (caspir/icycles=10)
• At Mopra> type rep 1 (sets the number of Repeat Integrations to 1)
• At Mopra> type fast (sets 0.5 arcsec pixels; alternatively, type slow for 0.25 arcsec pixels).
• At Mopra> type dark (creates a dark frame with time 0.3 sec and cycles 100)
• At Mopra> type isub ir001 (subtracts the dark from each idle frame: the dark frame should be ir001 if the dark was taken immediately after startnewnight: otherwise, the next run number is shown on the CASPIR display, the run just taken was one less. Without dark frame subtraction, the displayed image will be dominated by instrumental structure and no imaging information will be apparent.)
• At Mopra> type sub ir001 (subtracts a dark from each image taken)
• At Mopra> type fi k (this sets the filter to K; you can choose any filter from the list in the CM; note that many of the filters longward of K will saturate the array in the shortest possible exposure time; in particular the L filter can no be used - use the narrow band Cont3.6 filter for L-band imaging.)

** NOTE ** : The Technical Staff should have carried out the steps below when CASPIR was set up for observing. You will normally only need to shut down and restart if you have problems on MOPRA (e.g. a window crashes).

• At Mopra> type IR_SHUTDOWN (Note: IR_SHUTDOWN should not log you out of MOPRA. However, if you are logged out, log onto the Mopra workstation as user INFRARED [CM p. 71] - no password is required.)
• At Mopra> type IR_STARTUP [CM p.10]
• Answer No 'N' to the question about LSI software.
• Wait until "RELINQUISHING OWNERSHIP" message comes up in the top window before continuing - this can take several minutes.
• At Mopra> type caspir/display (This brings up the Caspir Status Display and starts taking data in Idle Mode).
• At Mopra> type _caspir (This resets the Caspir Commands syntax - most times!!!).
• Check that the setup on the console display is as required. Use the commands above under INITIATING CASPIR if changes are required.

CALIBRATING THE APERTURE AND TELESCOPE POINTING

• Choose a (mag 6-8) star from the '2.3 Metre Pointing Catalogue Coord File' (located in the console drawer) with a Zenith Distance of greater than 20° (to minimise field rotation during the calibration).
• On MAIA at TEL$ type track/coord R.A.  Dec Epoch (e.g. track/coord 06 45 12  -16 42 20 J2000)
• "Push" the star into the centre of the Idle Display Window (pixels 128,128) using the main console N-S-E-W offset buttons. Ensure that the Coordinate Selection buttons are set to 'RA/DEC' and that the Control Mode is set to 'Offset'.
• On MAIA at TEL$ type cali poi (short for calibrate pointing)
  The amount of offset can be set at TEL$ using the "offset/stepsize X" command, where X is a unit in arcseconds. Each push of a 'Slow' button moves the telescope by 1 offset unit, the 'Fast' buttons move the telescope by four units.
• N.B. FOR THE FIRST NIGHT OF THE RUN At TEL$ type cali aper a (this sets the spot on the CCD as the hub for field rotation) [CM p.13]
• Follow the on-screen prompts - the telescope will re-position the rotator 120 degrees [CM p.13]
• Use the N-S-E-W buttons to re-centre the star, once the field rotates the buttons may not "push".
• Now, and regularly during your observing, with your star centred, at TEL$ type calibrate pointing [CM p.12]

FOCUSING THE TELESCOPE

Using the IRIS Photometric Standards on page 147 of the CASPIR Manual, choose a star with a Zenith Distance of between 20 and 45 degrees [CM p. 12]

• At TEL$ type track HDxxxxx (insert the chosen star's HD number or type track/coord "starname" R.A.  Dec Epoch)

FOCUSING MASK METHOD [CM p. 17]

• At Mopra> type ,i>casp/fast (to select the Fast Camera).
• At Mopra> type casp/util 5 (to insert the focusing mask into the light path).
• Two star images will appear in the Idle Display Window. Use the Focus 'In' and 'Out' buttons until the minimum separation of the images is obtained (i.e. the two images lie in the same image row). The 'IN' button decreases the 'Focus position' readout - the focus number is given on the console display. For good images, the focus should be set to with 3 units of optimum.
  (Note: If using the Slow Camera (casp/slow), insert the focus mask in position 16 of the Upper Filter Wheel using casp/uf 16).
  (An alternative to manual focussing is to use auto focussing:
  At TEL$ type configure focus_control auto, then type focus 495, or whatever value is appropriate for the current temperature. The focus value decreases about 5 units per degree C.)

BEST IMAGE FOCUS METHOD

Watch the star image in the Idle Display Window. Use the Focus 'In' and 'Out' buttons until the finest star image is obtained, changing the Focus Position readout in the Display VDU by 3 units at a time.
If no star is visible in the Idle Display then (1) the star could be completely out-of-focus, or (2) the pointing could be off. If (2) then acquire a very bright star from the Almanac, place it near the array centre, and on MAIA at TEL$ type cali poi (Calibrate Pointing).

Note the outside temperature on the analogue dial - add the 'Temp Diff' as shown in the Display VDU. (This supplies the Temperature Inside).

Check the focus position against the Temperature - Focus Position Scale at the end of this document or in the CM. These numbers are approximate only. Manipulate the image in the Idle and Run Displays with the Function Keys [CM p. 71]

F2	- Zoom in.
F3	- Reset to normal zoom factors.
F4	- Zoom out.
F6	- Toggle cursor display.
F7	- Re-center image.
F19	- Toggle display of centroid/FWHM window for star near cursor.

SEEING ESTIMATION

• Place the Mopra cursor on the star in the Idle Display.
• At the Mopra keyboard press the F19 function key (this will calculate the FWHM of the star).
• Divide the FWHM value by 4 for the 0.25" Slow Camera or divide by 2 for the 0.5" Fast Camera to calculate the seeing in arc seconds.

DARK FRAMES AND BIAS FRAMES AND FLAT FIELDS

DARK FRAMES

• At Mopra> type casp/dark , or just dark (this command blanks the filter and aperture wheels and takes a dark frame using the currently set values of cycles and time).
  N.B. (Make a note of the file name of the Dark Frame e.g. ir001 for later Idle Display subtraction).

BIAS FRAMES

• At Mopra> type casp/bias , or just bias (this command sets the integration time, blanks the filter and aperture wheels and takes a bias frame using the shortest possible value of time and the current value of cycles).

FLAT FIELDS [Refer pp. 20, 21, 82, 83 CM]

• Close the primary mirror cover (Control Panel / Primary Mirror Cover button).
• Move the telescope to the zenith by typing at TEL$ zenith
• With the mirror cover CLOSED, move the upper windscreen over the telescope by typing ... TEL$ configure windscreen_control closed
• Open the primary mirror cover (Control Panel/Primary Mirror Cover button).
• At TEL$ type... switch flat on
• Set the Rotary Flat Field Illumination Control knob (below Lighting Control Panel) as detailed on page 21 of the Caspir Manual. An approx value of 30 is a good starting point. With an exposure of 30 seconds (Time=0.3 Cycles=100) you are aiming for a 'Lights On' count of about 3000 and a 'Lights Off' count of between 5 and 500, depending on the filter.
• At Mopra> casp/obj = flatk_on or casp/obj = flatj_off, as appropriate (This sets the object name for the next integration i.e Flat Field - Filter K - Lights On etc).
• Take Flat Fields with the Mopra> casp/run command in 'Lights On' and 'Lights Off' pairs for each filter and image scale required as detailed in the Caspir Manual pages 20-21 and 82-83.
• Upon completion of the Flat Fields switch the illumination off at TEL$ with switch flat off
• Close the mirror cover (Control Panel/Primary Mirror Cover button).
• Withdraw the upper shutter with TEL$ config windscreen_control vertical_only
• Close the mirror cover (Control Panel/Primary Mirror Cover button).

DATA TAKING

• A single integration is taken with the Mopra> casp/run command.
• Or a scripted Do file can be executed by typing at Mopra> do file_name (e.g. do stdk or whatever .DO files the observer is using: this is the only sensible way to use CASPIR)
• Move to the next star and repeat the casp/run command or execute the next DO file.

N.B. The 'Idle Display' window is only updated when Caspir is not actually taking data. Run data displays in the 'Run Display' window.

SHUTDOWN

CASPIR ...

Generally, the infrared system should be left running at the end of a night. The dewar should be left blanked off with an lfi blank command to avoid prolonged exposure to saturated light levels.

• At Mopra> type lfi blank (lower filter position = light path blocked).

CLOSING THE TELESCOPE

• At TEL$ type park
• When the telescope stops moving ... at TEL$ type shutdown
• Check that the mirror cover and building cover have closed.
• At the end of an observing run, close the MANUAL DUST COVER at the top of the IMB at the Cassegrain level.

DATA ARCHIVING [CM p.44]

CASPIR data files are written to the MOPRA data disk as FITS files. These files are accessible from Unix machines in dated subdirectories of the directory /data/mopra/. Data files can be copied from MOPRA to a Unix machine by typing the following into the console of one of the Unix machines (ex. MOULDY):

Change into your data directory e.g.
cd /data/moist2/sbrook (your directory name)
mkdir 17oct00 (use the observing date)
cd 17oct00
cp /data/mopra/17oct00/ir*.fits .
(if you experience problems, send email to sysman explaining the problem - sometimes the required daemon is not running.)
chmod -x * (unsets executable status)

Data are archived to DAT or Exabyte tapes on drive ex0 on MUDSLIDE. It is the responsibility of observers to provide their own tapes.

Typically ~100 Mbytes of data are produced in a single night of direct imaging, so data from several nights can fit on one tape.

Log into mudslide from one of the Unix machines and save the data:
rlogin mudslide (or telnet mudslide)
allocate ex0 (the list of possible allocate addresses is on the front of mudslide)
cd /data/mopra
tar cv dir_name (E.G. 17oct00 archive data in subdirectory 17oct00)
The command etar writes a tar file at the end of existing data on a tar tape, and is useful for writing successive nights to the one tape.
mt offline (Take tape offline)
deallocate ex0 (Deallocate tape drive so it can be used by others.)
Remove the tape.

THE TELESCOPE PADDLE

A telescope paddle appears on the MOPRA workstation screen during system startup (if ENLIST IR has been typed). This paddle consists of a 3 x 3 grid with NSEW boxes labeled accordingly. The first mouse button (the left one for a right-handed setup) is used to offset the telescope by clicking on the appropriate box. All eight outer boxes respond in the obvious way. The first mouse button does not respond to clicks in the central square.
The default telescope offset is 1.0 arcsec. This offset can be increased in factors of two by clicking the second (middle) mouse button in the central square. Similarly, it is decreased by clicking the third mouse button in the central square. The second and third mouse buttons do not respond to clicks in any other squares.

WINTER/SPRING TEMPERATURE - APPROXIMATE FOCUS POSITIONS

Temp Outside	Temp Inside	Focus Position
16.0	16.7	490
15.5	15.9	489
14.2	14.8	487
12.5	13.7	476
10.5	11.6	474
6.1	8.5	467
6.0	7.7	461
5.2	7.4	459
5.2	7.2	459
5.6	6.4	456
5.2	6.0	453
5.2	6.6	453
5.2	5.8	451
5.1	6.2	450
4.5	5.0	449
4.8	5.3	448
4.8	5.9	447
4.6	5.5	447
3.9	4.5	444

COMMON CASPIR COMMANDS

casp/it n (Sets the Idle Time to n)
casp/ti n (Sets the Run integration time to n)
casp/ic n (Sets the number of coadd Idle Cycles to n)
casp/cy n (Sets the Run integration coadd cycles to n)
casp/obj=object name (Sets the object name for the next run)
casp/rep n (Sets the number of images (data files) to be obtained at the next run)
casp/run (Starts integration creating a data file named IRxxx, where xxx is the current Run No.)
casp/dark (Takes a Dark frame)
caspir/bias (Takes a Bias frame)
casp/do filename (Runs a DO file)
casp/izauto (Sets the Idle Display to auto grey scaling)
casp/zauto (Sets the Run Display to auto grey scaling)
casp/noizauto (Turns off the Idle Display auto grey scaling)
casp/nozauto (Turns off the Run Display auto grey scaling)
casp/izmin=value (Sets the lower bound for the scale of the Idle Display)
casp/izmax=value (Sets the upper bound for the scale of the Idle Display)
casp/zmin=value (Sets the lower bound for the scale of the Run Display)
casp/zmax=value (Sets the upper bound for the scale of the Run Display)
casp/abort (Aborts the current run and .DO sequence)
caspir/information (Displays the Main and Miscellaneous Display screens)
_caspir (Resets the predefined CASPIR commands - sometimes they can be accidently redefined by incorrect use, in particular by using a "=" when not required. See CM, p.57 for a list of the command shortcuts.)

IDLE AND RUN DISPLAY FUNCTION KEYS [CM p. 71]

F2	- Zoom in.
F3	- Reset to normal zoom factors.
F4	- Zoom out.
F6	- Toggle cursor display.
F7	- Re-center image.
F19	- Toggle display of centroid/FWHM window for star near cursor.

ONLINE SKY SUBTRACTION

At Mopra> type casp/sub=filename or casp/isub=filename (This subtracts the (filename) image from every Run or Idle Display image that is uploaded - data written to files does not have the subtraction performed. The resulting displayed image can be much improved. The saved image is not affected by this process.) [CM p. 15 & p.65-66]

FIELDS OF VIEW

Fast Camera 0.5" / pixel focal plane scale (2x2 arcmin image)
Slow Camera 0.25" / pixel focal plane scale (1x1 arcmin image)

ROTATING THE FIELD OF VIEW

The field of view can be rotated about the defined Aperture by changing the Position_Angle value as displayed on the Display Console. At TEL$> type... Position_Angle nnn (where nnn is the new angle). I.E. to rotate the field 15º clockwise from a former position angle of say 179.4, enter Position_Angle 194.4 A position angle of 164.4 would rotate the field 15º counter-clockwise.

APERTURE, FILTER, UTILITY AND LENS WHEEL CONTENTS AND POSITIONS

[Refer to pp. 144 & 145 of the Caspir Manual]

Rev 04/04/01