Autoslit is used to create slit-masks for the LRIS instrument from a list of object positions. Given an input file of object positions and a parameter file to control the operation of the program, Autoslit may be used to automatically and/or interactively match slits of various shapes to a selection of the objects. Autoslit will produce output files for the LRIS slitmask mill machine and the slitmask alignment program.
Autoslit and a number of support files are available via the URL:
http://astro.caltech.edu/~pls/autoslit/
> gunzip autoslit.tar.gz
> tar xvf autoslit.tar
Alternatively, the version of 'tar' from GNU includes an option to
use 'gunzip' directly:
> tar zxvf autoslit.tar.gz
This process will create a directory, autoslit-3.0x, which
contains the source code and example input files for Autoslit.
Autoslit 3.0 is entirely terminal-based, although a device capable of line graphics (e.g., Tek 4010 emulator, X Window System) is needed for interactive slit assignment. A PostScript printer is needed for printing the hardcopy plots of the final slit setup.
This file contains parameters settings which control the behavior of Autoslit and define addition slit types. Autoslit will prompt the user for the name of this file.
The parameter file consists of two sections, with a structure as follows:
<keyword> <value>
<keyword> <value>
...
END
<slit definition block>
<slit definition block>
...
END
FILENAME <name> - name of input object file
FILEOUT <name> - root file name for output files
PRIORITY <int> - object priority to divide objects
RANK_TOP [1|2] - number of slit ranks in top half
RANK_BOT [1|2] - number of slit ranks in bottom half
SLIT_WID <real> - width of slits in arc-sec
SLIT_LEN <real> - minimum length of slits in arc-sec
SLIT_SEP <real> - separation of slits in arc-sec
EPOCH <real> - epoch for slitmask use
TEMP <real> - temperature for refraction calc in Celsius
PRESS <real> - pressure for refraction calc in mm of Hg
WAVE <real> - wavelength for refraction calc in Angstroms
LAT <real> - latitude of observatory in decimal degrees
POS_ANGL <real> - position angle in decimal degrees
HOUR_ANG <real> - hour angle in decimal degrees
MIRROR <object> - use guide star
ENG_TEST <boolean> - engineering test?
ADC <boolean> - atmospheric dispersion corrector in use?
INTERACT <boolean> - interactive slit assignment?
VERBOSE <boolean> - verbose output?
For the values of the boolean keywords, any string beginning
with one of the letters [tyTY] denotes true/yes, while any
string beginning with one of the letters [fnFN] denotes
false/no.
TILTS <int>
<object> <pos angle> <min up> <min down>
<object> <pos angle> <min up> <min down>
...
The first line specifies the number of tilted slits to be
defined. Each subsequent line defines one tilted slit.
Each slit is defined by the name of the object on which
the slit will be placed (from the input object file), the
position angle of the slit, and the minimum extent of the
slit in arc-seconds, above and below the position of the
object.
ARCS <int>
<name> <ra> <dec> <epoch> <radius> <min pa> <min pa>
<name> <ra> <dec> <epoch> <radius> <min pa> <min pa>
...
The first line specifies the number of arc slits to be
defined. Each subsequent line defines one arc slit. Each
slit is defined by a name (arc slits need not be placed on
objects), the position of the center of curvature of the
arc, the epoch of the center position coordinates, the
radius of curvature, and the position angles of the ends
of the slit. The RA and Dec of the center should each be
defined by three numbers (hours|degrees, minutes,
seconds), separated by whitespace. The radius should be
positive for arcs to the right of the center, and negative
for arcs to the left of the center. The slit will extend
along the smallest arc between the specified position
angles.
SEGMENTSThe first line specifies the number of points to be defined for line segment slits. Each subsequent line defines one point in a line segment slit. Each point is defined by the name of the line segment slit (line segment slits are not placed on objects), the position of the point, and the epoch of the position coordinates. All consecutive line segment points which share the same slit name will be connected to form a single slit. For example, the above declaration would create two slits, one with 3 points (name1), and another with 4 points (name2). See the file Examples/test.in for more examples. Note that the value on the first line of the block indicates the number of points in the line segment slits, not the number of slits.<name1> <ra> <dec> <epoch> <name1> <ra> <dec> <epoch> <name1> <ra> <dec> <epoch> <name2> <ra> <dec> <epoch> <name2> <ra> <dec> <epoch> <name2> <ra> <dec> <epoch> <name2> <ra> <dec> <epoch> ...
BOXES <int>
<object> <size>
<object> <size>
...
The first line specifies the number of box slits to be
defined. Each subsequent line defines one box slit. Each
slit is defined by the name of the object on which the
slit will be placed (from the input object file), and the
size of the box, in arc-seconds.
This file must contain one-line descriptions of each object of interest in the field, in a format identical to that used for Palomar Observatory's Norris spectrograph. This format is described in more detail in the file GET_OBJ.C, but is summarized as follows:
Each object description line consists of: <pre> <name> <prior> <mag> <ra> <dec> <epoch> <equinox> <ra_pm> <dec_pm> where
<name> = object identifier (or name)
<prior> = object priority as assigned by the observer
<mag> = object magnitude
<ra> = object right ascension: <hours> <minutes> <seconds>
<dec> = object declination: <degrees> <minutes> <seconds>
<epoch> = epoch of the object's coordinates
<equinox> = object equinox
<ra_pm> = object proper motion in right ascension in arcsec/yr
<dec_pm> = object proper motion in declination in arcsec/yr
Although the order of the fields is important, spacing between the fields does not matter.
The lines may be given in any order, *except* the first line, which should have a priority of '9999' and should provide the coordinates of the center of the field of interest.