ALFOSC
Sequencer Command Documentation
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System | Command | Arguments | Description | Type |
alfosc |
abort |
[-d] |
Aborts an ongoing exposure (see also expose). |
DET |
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 |
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 |
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 |
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 |
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 |
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.
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