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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 abort [-d] Aborts an ongoing exposure (see also expose). DET
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 autoshow_off [-d] Turns off the automatic image display while reading out. If DS9 is running it will be terminated. DISP
alfosc autoshow_on [-d] Turns on the automatic image display while reading out. If no DS9 is running one will automatically be started. DISP
alfosc dark [-d] [-t] [-f] [-n]<tt> Makes a dark exposure of <tt> seconds. If <tt> is set to zero a BIAS exposure is made. If the exposure time is larger then 60 seconds, automatic remnant removal is done before the exposure starts. If the option [-f] (fast mode) is used, the prompt will be returned when the exposure time is over and before the readout begins. If the option [-n] is used, there will be no automatic remnant removal. DET
alfosc display [<file>] Loads an image into the ALFOSC DS9 display. If no <file> is specified, the last image obtained will be loaded. If no DS9 display exists, one will be started. DISP
alfosc dither [-e] [-t] [-nowakeup] <pattern> <offset_size> <tt> Takes single exposures at each pointing of a dither pattern. The pointings in a dither pattern are symmetrical around the initial pointing, except for the ABBA scripts, which starts with an exposure on initial pointing. It is possible to specify a negative offset size, in which case the offsets are performed in the opposite direction.
  • [-e]: Echo script on stdout, do not execute
  • [-t]: Simulate exposure only
  • [-nowakeup]: no astrowakeup at the end of script
  • <pattern> predefined dither pattern.
  • <offset_size> telescope offset in arcsec between each exposure.
  • <exptime> exposure time at each pointing.
The dither pattern can be one of the following listed below:
  • 2X : 2-point (X)
  • 3X : 3-point (X)
  • 5X : 5-point (X)
  • 2Y : 2-point (Y)
  • 3Y : 3-point (Y)
  • 5Y : 5-point (Y)
  • 5D : 5-point (dice 5)
  • 4G : 2x2 grid
  • 9G : 3x3 grid
  • 16G : 4x4 grid
  • ABBAX : A-B-B-A (X)
  • ABBAY : A-B-B-A (Y)
Usage example:
  alfosc.dither 3X 20 15   Makes a 3-point X dither pattern with a 15s exposure at each dither point and a 20" offset between each exposure.
DET
alfosc easyflat [-f] [-silent] [<N>] A script to do <N> imaging skyflats. If the argument is not given, it will only do one skyflat. Takes a small unbinned Y-windowed flat image, finds median value and bias level (using qc-user@elena:alfosc/skyflats/alfoscskycounts.py), sets back the original window/binning and fires off an exposure aiming for 100 kADU. If the test-image count rate is too high or too low, then the script either retries the test image after 20 seconds, or exits (depending on morning or evening). Once a real flat-field image is taken, this and any subsequent flat-field images are also analysed, and the next exposure time is computed accordingly. The exposure-time algorithm is based on the requirements
  • the minimum exposure time is 1 second
  • the maximal exposure time is 300 seconds
  • the minimum count level is 30 kADU
  • the maximal count level is 250 kADU
  • the aim is 100 kADU
When the sky is dark, and the counts aimed-for cannot be reached within 300 seconds, the script will still take a 300s flat if the expected counts are above the minimum acceptable count level (30 kADU). Similarly, for bright sky, a 1-second flat will be taken if the counts will be below the maximal count level of 250 kADU. Does a teloffset after each flat during readout, in a spiraling sequence, with a grid spacing of 15 arcsec. Does not do any instrument setup. Switches on autosave, and leaves it on. Switches on remsave (to /data/service/calib/), and switches it off at exit. Does not alter amplifier settings. Note: polarimetry flats will only work with polwin.

If the -f flag is given, for fast mode, the prompt will be returned to the shell during the last readout.

If the flag -silent is given, a sound will not be produced after end of execution.

DET
alfosc expose [-d] [-t] [-f] [-n]<tt> Makes an exposure of <tt> seconds. Remnant removal is made before the exposure starts, if the exposure time is larger then 60 seconds. If the option [-n] is used, no remnant removal is done. To abort the exposure press "Control-C". This command checks if ALFOSC, FASU and FAPOL are ready before beginning the exposure. If 90 seconds occurs and it is not ready this command will time out. If the option [-f] (fast mode) is used, the prompt will be returned when the exposure time is over and before the readout begins. If [-f] is used, make sure that "alfosc.wait-camera-state idle"-command is given before any "alfosc_camera_commands". If the exposure time is larger than 300 seconds, the time left until the rotator reaches its limit will be checked. If there is not time enough to complete the exposure, an error will be generated and the exposure will not start. DET
alfosc focus [-e] [-n <N>] [-nodefault] [-t <nn>] [-a <mode>] Fully automated focus script for ALFOSC.
[-n <N>]: Number, <N>, of maximal loops, default is 3.
[-t <nn>] Expose <nn> seconds. Default is 10.
[-nodefault]: Start from actual focus rather than default focus.
[-a <mode>]: Acquisition mode. <mode> can be:
  • noacq: Use current pointing for focusing.
  • nearest: Use nearest focus field from current pointing.
  • optimal: Use nearest focus field between 60-70 degrees altitude (default)
Focus is determined without any filter in the beam. Filter and any other ALFOSC instrument & detector settings will be saved before running the focus script and restored at the end.
The 'focus' command is the recommended way of focusing the telescope. In case the command fails, for instance if too few stars are detected in the image, the focus can be determined in a more interactive mode by using the commands focuspyr-setup, expose, focuspyr, focus-position (see documentation on these commands for further information).

Usage example:
  alfosc.focus -n 4 -t 15 -a nearest   Focuses the telescope using the nearest focusfield, doing 4 loops with individual exposures of 15s.

TEL
alfosc focus-offset [-e] [-d <nn>] Optics in the beam introduces a telescope focus offset (see table). The 'focus-offset' command checks what is currently in the FASU and ALFOSC filter wheels and applies the corresponding focus offset (using foc-del) when possible. The focus offset introduced by a retarder plate in polarimetry mode is also accounted for. Be very careful when using this command. Focus offset for many optical elements are not known and as a consequence the telescope may in fact not be in focus even after using this command. If the focus offset is not known, 0 will be assumed. If this occurs, a warning message will appear both in the talker window and in the sequencer window. Several warning messages may appear if several optical elements in the beam have unknown focus offsets. The final telescope focus offset applied is the sum of the offsets for the element in each wheel, and may therefore be wrong if any offset is unknown. Do not use this command in scripts unless you are absolutely sure that the focus offset are known for all optical elements to be used.
If you intentionally wish to defocus the telescope (for instance when observing very bright targets), call the script with the [-d] flag, specifying the number of focus units to defocus the telescope with, for instance
focus-offset -d 200
will defocus the telescope with 200 units with respect to optimal focus. Reasonable defocus values ranges from 50-2000 units.
TEL
alfosc imexam Initiates an IRAF imexam session on the image currently loaded into the ALFOSC DS9. While active in the imexam session, no further commands can be issued from the sequencer window. To kill the imexam session type q on the image in the postprocessing display.

CURSOR KEY COMMANDS:

?       Print help
a       Aperture radial photometry measurement (see above for output)
c       Column plot
e       Contour plot
f       Redraw the last graph
j       Fit 1D gaussian to image lines
k       Fit 1D gaussian to image columns
l       Line plot
m       Statistics
            image[section] npixels mean median stddev min max
q       Quit
r       Radial profile plot (see above for output)
s       Surface plot
x       Print coordinates
            col line pixval [xorign yorigin dx dy r theta]
DATA
alfosc log-comment "Comment in quotes" [file1 file2 ...] When invoked with just the comment, it will be applied to the latest available image with a prefix for the current night (which starts at noon) and the sequencer's instrument.

If image names are provided, the program will test the existence of ALL them before applying the change.

Eg.

        $ alfosc.log-comment "This is a comment"
        $ alfosc.log-comment "Comment for two" ALug170154 ALug170155
Notice that there's no need to add the ".fits" after each image's name

If no arguments are provided, a usage message is displayed

DATA
alfosc mdark [-t] [-n] [-f]<tt> <nn> Makes <nn> dark exposure of <tt> seconds. To abort the exposures press "Control-C". The image type (IMTYPE keyword) will be set to "DARK" if the exposure time is non-zero and "BIAS" if it is zero. If the exposure time is larger then 60 seconds, automatic remnant removal is done before the exposure starts. If the option [-f] (fast mode) is used, the prompt will be returned when the exposure time is over and before the readout begins. If the option [-n] is used, there will be no automatic remnant removal. DET
alfosc mexpose [-t] [-n] [-f]<tt> <nn> [<imtype>] Makes <nn> exposures of <tt> seconds. To abort the exposures press "Control-C". The <imtype> option (IMTYPE keyword) is optional and must be a text string without spaces. There are reported problems with this command that have not yet been solved. If you experience this, please use the alternative command single-mexpose.Remnant removal is made before the exposure starts, if the exposure time is larger then 60 seconds. If the option [-n] is used, no remnant removal is done. If the option [-f] (fast mode) is used, the prompt will be returned when the exposure time is over and before the readout begins. If [-f] is used, make sure that "alfosc.wait-camera-state idle"-command is given before any "alfosc_camera_commands". If the exposure time is larger than 300 seconds, the time left until the rotator reaches its limit will be checked. If there is not time enough to complete the exposure, an error will be generated and the exposure will not start. DET
alfosc object [-d] <text> Sets the FITS keyword OBJECT to <text>. DATA
alfosc photstd [-e] [-a mode] [-f filterIDs] Automatic exposure of standard stars. Goes to nearest standard field and does exposures in filters UBVRi as default - or filters specified by the user.
Currently supports UBVRi and in the future sdss ugriz. Other filters can be done, but will have the same exposure times, set by the variable default_time.
Instead of going to the nearest field, aquisition mode can be set to a specific target. The TCS name must be used, see http://www.not.iac.es/instruments/alfosc/photstd/.

Usage example: alfosc.photstd -a A_PG1633+099 -f "74 75 120 110"

DATA
alfosc readout [-d] Closes the shutter and reads out the ccd. You have to put the exposure in the background first. This is achieved by pressing Ctrl+Z in the sequencer where the expose command is running, followed by running the command bg. Note that this command does not work correctly when using a window in Y direction: data from a wrong window will be saved to file. DET
alfosc readspeed [-d] <readout_speed> Sets the CCD readout speed to <readout_speed> kpix/second. Valid values for <readout_speed> are 100, 200, 400 or 800. DET
alfosc remove_remnants Remove remnants from the CCD when saturation has taken place. DET
alfosc rempath [-d] <nn> Sets the remote saving path to <nn>. DATA
alfosc remsave_off [-d] Turns off remote saving. DATA
alfosc remsave_on [-d] Turns on remote saving. DATA
alfosc reset-log The script will use infosys.kill to reset the monitoring system, then it will wait for a set number of seconds, and at last it will instruct the obslog to show the listing for alfosc, all the while informing the user about what is happening

If there's any error, the script will notify the user and suggest further actions.
DATA
alfosc resetxy [-d] Resets the ccd binning to 1, the X and Y size to maximum and the X and Y beginning to 1. DET
alfosc teloffset <n> <m> Offsets an object on the CCD <n> arcseconds in X direction, <m> arcseconds in Y direction. TEL
alfosc wheels [-e] [-s <slit>] [-g <grism>] [-c <crossdisp>] [-f <filter>] [-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 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
alfosc xbeg [-d] <nn> Sets the X beginning to <nn>. DET
alfosc xbin [-d] <n> Sets the binning factor in the X direction to <n>. DET
alfosc xsize [-d] <nn> Sets the X size to <nn>. DET
alfosc ybeg [-d] <nn> Sets the Y beginning to <nn>. DET
alfosc ybin [-d] <nn> Sets the binning factor in the Y direction to <n>. DET
alfosc ysize [-d] <nn> Sets the Y size to <nn>. DET

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: November 23 2011