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ALFOSC Sequencer Command Documentation

Go to the SEQUENCER Reference Manual Main Page.

Instrument : ALFOSC
Observing Mode: ANY IMA SPEC POL
Command Type: ANY DATA DET DISP INST TEL
Usage: BASIC GENERAL STAFF
Description: SHORT LONG

SystemCommandArgumentsDescriptionType
alfosc allopen [-e] Will move all ALFOSC/FASU optical wheels to the OPEN position. Only wheels that according to the ALFOSC status are not already OPEN will be commanded to move. FASU wheels will always be commanded to move. INST
alfosc aperture [-d] [id] [name] [pos] [ready] [step][orient] <n> Moves aperture wheel to slot number <n>. [id] returns the NOT ID of the element in the light path. [name] returns the name of the element in the light path. [pos] eturns the position [0-7] of the element in the light path. [ready] returns '0' if the element is moving, '1' if it is ready. [step] returns the step position [0-320000] of the element in the light path. [orient] returns the optical orientation of the element in the light path. INST
alfosc callamptimes [-s ] [-xbin N] [-ybin M] <lampID> <grism> Returns the exposure time for a calibration lamp exposure for ALFOSC spectroscopy.

Accounts for grism and lamp type using the Overheads Table. Optionally accounts for binning. Optionally accounts for slit width, but only for Halogen exposures.

If the Table has a '0' entry for the requested grism/lamp combination, then the script will bomb giving the 'Unsupported setup' error. This script does not do any instrument setup. This script does not check any instrument setup. The output of the script solely depends on the command line arguments, regardless of the current setup.

INST
alfosc carriage [-d] [pos] [ready] [action] Moves FAPOL carriage in or out with the [action] keyword. [action] can be 'in', 'IN', 'out' or 'OUT'. [pos] returns '1' if the carriage is in the lightpath, '0' if it is out. [ready] returns '0' if the element is moving, '1' if it is ready. INST
alfosc fasua [-d] [id] [name] [pos] [ready] <n> Moves FASU wheel A to position <n>. [id] returns the NOT ID of the element in the light path. [name] returns the name of the element in the light path. [pos] returns the position [0-6] of the element in the light path. [ready] returns '0' if the element is moving, '1' if it is ready. INST
alfosc fasub [-d] [id] [name] [pos] [ready] <n> Moves FASU wheel B to position <n>. [id] returns the NOT ID of the element in the light path. [name] returns the name of the element in the light path. [pos] returns the position [0-6] of the element in the light path. [ready] returns '0' if the element is moving, '1' if it is ready. INST
alfosc filter [-d] [id] [name] [pos] [ready] [step][orient] <n> Moves filter wheel to position <n>. [id] returns the NOT ID of the element in the light path. [name] returns the name of the element in the light path. [pos] returns the position [0-6] of the element in the light path. [ready] returns '0' if the element is moving, '1' if it is ready. [step] returns the step position [0-320000] of the element in the light path. [orient] returns the optical orientation of the element in the light path. INST
alfosc focuspyr-setup [-e] [-filter] Script to setup ALFOSC for focussing.
  • moves the FocusPyramid in.
  • puts the aperture wheel to open position.
  • moves mirror and retarder out of the beam if they are in.
  • turns off all ALFOSC calibration lamps.
  • windows the read-out using alfosc.focuswindow.
  • by default puts all filter wheels (FASU A,B and ALFOSC) to open position.
  • if optional argument -filter is used, the filter wheels will be left as they are. NB: this mode will not touch the filter wheels even if there is filters in all 3 wheels!
INST
alfosc grism [-d] [id] [name] [pos] [ready] [step][orient] <n> Moves the grism wheel to position <n>. [id] returns the NOT ID of the element in the light path. [name] returns the name of the element in the light path. [pos] returns the position [0-6] of the element in the light path. [ready] returns '0' if the element is moving, '1' if it is ready. [step] returns the step position [0-320000] of the element in the light path. [orient] returns the optical orientation of the element in the light path. INST
alfosc lamp [-d] [position] <n> <m> Turn on/off lamp no. <n>, where <n> is [1-4] and <m>='1' to turn on and <m>='0' to turn off. Current (29/10-2007) lamp setup: Lamp 1 is "He" Lamp 2 is "Ne" Lamp 3 is "Halogen" Lamp 4 is "ThAr Hollow Cathode". A timer will turn off any lamp after 1200 sec. Subsequent commands to turn on a lamp will result in the timer being reset to 1200 seconds. [position] returns a 4 bit pattern corresponding to the state of the 4 lamps: If bit no. 1 is set, lamp no. 1 is on, else off If bit no. 2 is set, lamp no. 2 is on, else off If bit no. 3 is set, lamp no. 3 is on, else off If bit no. 4 is set, lamp no. 4 is on, else off INST
alfosc mirror [-d] [pos] [ready] <n> Moves calibration mirror in or out, <n>=1 for in and <n>=0 for out. [pos] returns the position of the calibration mirror. '1' is in, '0' is out. [ready] returns '0' if the element is moving, '1' if it is ready. INST
alfosc optics [-e] [-s <slit>] [-g <grism>] [-f <filterID>] [-d <wheel>] [-m] [-a] [-p] [-o] [-h] Searches ALFOSC and FASU wheels for optical elements. Returns the wheel (fi, fa, fb, ap, gr), the position (integer number) and the optical element. Optional output (with flag -a) returns also the alignment tag (Y/N). Optional output (with flag -p) returns the slit position (x and y). This script can also be used to turn the corresponding wheel(s) to searched position(s) with optional flag -m. Note that this moves only the corresponding wheels, leaving other wheels as they were. Flag options:
  • -g <grism>
    Searches the grism and the filter wheel with given <grism> e.g. "#4"
  • -s <sslit>
    Searches the aperture wheel with given <slit> e.g. 0.75
  • -f <filterID>
    Searches the filter, FASUa and FASUb wheels with filter <filterID> e.g. 76
  • -m
    Turns the wheel(s) so that the searched optical element(s) is in the light beam
  • -d <wheel>
    Displays the content of the wheel, <wheel> is the name of the wheel: filter/fasua/fasub/grism/slit (Cannot be used with flags -s/-g/-f)
  • -a
    Prints out the alignment tag (Y/N) in the output
  • -p
    Prints out the the slit position (x, y) in the output
  • -o
    Prints out the 'Open' positions for every wheel. (Cannot be used with flags -s/-g/-f)
  • -h
    Prints out help
Usage example:
  alfosc.optics -f 76 -g "#4" -s 0.75 -a -p
Returns:
  fi 4 "R_Bes 650_130"
  gr 1 Y "Grism_#4"
  ap 0 Y 1050 1008.79 "Slit_0.75""
INST
alfosc polarizer [-d] [pos] [ready] <n> Moves the polarizer to angle <n>, where <n> is any multiple of 22.5 between '0' and '337.5'. [pos] returns the current polarizer position. [ready] returns '0' if the element is moving, '1' if it is ready. INST
alfosc snapshot [store|restore] Snapshot facility for ALFOSC. Uses the store and restore commands on the systems ALFOSC,FASU & CCD8. This command is useful to conveniently save the current state of the instrument and detector for later restoring, for instance after executing scripts that alter the setup. Note that this will only work as expected as long as the wheel contents are not changed! INST
alfosc wait-camera-state [idle|integrating|readout|not-integrating] The sequencer prompt will not be returned until the state of the ALFOSC camera matches the state given as an argument. This is useful in scripts, for instance to execute commands when the camera is reading out. For multiple exposures, the command will wait until the state of the last exposure is matched. Caution: Do not use this command to catch camera states that is expected to last only a short time (less than around 1 second). The state change may not be detected by the command, and the sequencer prompt may never be returned. Please note that waiting for the state to be 'readout' before an exposure is started will result in the command waiting forever. INST
alfosc wait_alfosc_ready [-d] Waits until all the following items are ready (not moving): FASU A and B, aperture, filter, grism, ALFOSC focus, FAPOL carriage and FAPOL polarizer. INST
alfosc wheels [-e] [-s <slit>] [-g <grism>] [-c <crossdisp>] [-f <filterID>] [-d <diffuserID>][-nowait] [-forceFASU] Script to setup all 5 ALFOSC wheels, in quickest possible way. Possible arguments are:
  • -s <slit>   aperture-wheel item string
  • -g <grism>   grism string
  • -c <crossdisperser>   crossdisp grism string
  • -f <filterID>   filter ID number
  • -d <diffuserID>   diffuser ID number
  • -nowait   exit while wheels are moving
  • -forceFASU   force the FASU wheels to move even when at required position
Each wheel defaults to the OPEN position, unless it needs to be put to a different position as requested through the command-line arguments. Consequently, without any arguments alfosc.wheels puts all wheels to open. The script uses alfosc.optics to check the feasibility of the requested setup. If feasible, the wheels will be moved to put the requested items in the beam. If wheels are already in the correct position they will not be exercised, except for the FASU wheels when flag -forceFASU is given. If a requested setup is not possible, an error will result, and no wheels will be moved. Note: grism/slit strings should be unique. A list of optical items can be found here. Note: filter ID numbers can be found here. Note: the Focus_Pyr is considered a grism!! Note: for spectroscopy the horizontal/vertical requirements for the optical elements are tested.
Usage examples:
  • alfosc.wheels -f 74   sets up for imaging with filter #74
  • alfosc.wheels -g Focus_Pyr   sets up for focusing without filters
  • alfosc.wheels -s Slit_1.0 -g "#4"   sets up for spectroscopy with slit 1.0" and Gr#4
  • alfosc.wheels -s Slit_1.0 -g "#4" -f 93   sets up for spectroscopy with slit 1.0" and Gr#4 and blocking filter #93
  • alfosc.wheels -s Ech_0.8 -g "#9" -c "#10"   sets up for Echelle spectroscopy with slit 0.8" and Echelle Gr#9 and cross disperser Gr#10
INST

In scripts, the syntax alfosc.<command> should be used.
If a part of a command is written in <angle brackets>, this is an argument that should be replaced with a value.
If a part of a command is written in [square brackets], this is an optional argument or flag.
When available, the optional flag -d will write extended debugging information to the log.
When available, the optional flag -e will show the script on standard output instead of executing the commands.
When available, the optional flag -t will only make a simulated exposure. Useful for testing scripts.

Type definitions:
DATA: All commands related to handling/modifying data (editing fits-headers, post-processing etc.).
DET: Commands related to operations with the detector.
DISP: Commands related to displaying images on the instrument computer.
INST: Commands related to operations with the instrument.
TEL: Commands related to operations with the telescope.

Back to top Last modified: January 26 2023