SCAT(7)SCAT(7)
NAME
scat – sky catalogue and Digitized Sky Survey
SYNOPSIS
DESCRIPTION
Items are read, one per line, from the standard input
and looked up in the catalogs.
Input is case-insensitive.
The result of the lookup becomes the set of objects available
to the database commands.
After each lookup or command, if more than two objects are
in the set,
Number 1234 in the New General Catalogue of Nonstellar Objects, NGC2000.0. The output identifies the type
unhandled troff command .RB(
Like NGC references, but from the Index Catalog.
Number 12345 in the Smithsonian Astrophysical Star Catalogue. Output identifies the visual and photographic magnitudes, 2000.0 coordinates, proper motion, spectral type, multiplicity and variability class, and HD number.
Catalog number 4 in Messier’s catalog. The output is the NGC number.
Catalog number 1701 in the Abell and Zwicky catalog of clusters of galaxies. Output identifies the magnitude of the tenth brightest member of the cluster, radius of the cluster in degrees, its distance in megaparsecs, 2000.0 coordinates, galactic latitude and longitude, magnitude range of the cluster (the ‘distance group’), number of members (the ‘richness group’), population per square degree, and popular names.
The set of NGC objects of the specified type. The type may be a compact NGC code or a full name, as above, with no blank.
Names are provided in double quotes.
Known names are the Greek
letter designations, proper names such as Betelgeuse, bright variable stars,
and some proper names of stars, NGC objects, and Abell clusters.
Greek letters may be spelled out, e.g.
Coordinates in the sky are translated to the nearest ‘patch’, approximately one square degree of sky. The output is the coordinates identifying the patch, the constellations touching the patch, and the Abell, NGC, and SAO objects in the patch. The program prints sky positions in several formats corresponding to different precisions; any output format is understood as input.
All the patches in the named constellation.
The planets are identified by their names.
The names
The commands are:
Add the named item to the set.
Flatten the set and cull it, keeping only the specified classes.
The classes may be specific NGC types,
all stars
Complement to
Some items such as patches represents sets of items.
Print the contents of the set. If the information seems meager, try flattening the set.
Flatten the set,
expand the area of the sky covered by the set to be
Run
Expand and plot the set in a new window on the screen.
Symbols for NGC objects are as in Sky Atlas 2000.0, except that open clusters
are shown as stippled disks rather than circles.
Abell clusters are plotted as a triangle of ellipses.
The planets are drawn as disks of representative color with the first letter of the name
in the disk (lower case for inferior planets; upper case for superior);
the sun, moon, and earth’s shadow are unlabeled disks.
Objects larger than a few pixels are plotted to scale; however,
The option
The output is designed to look best on an LCD display.
CRTs have trouble with the thin, grey lines and dim stars.
The option
Display the section of the Digitized Sky Survey (plate scale
approximately 1.7 arcseconds per pixel) centered on the
given right ascension and declination or, if no position is specified, the
current set of objects. The maximum area that will be displayed
is one degree on a side. The horizontal and vertical sizes may
be specified in the usual notation for angles.
If the second size is omitted, a square region is displayed.
If no size is specified, the size is sufficient to display the centers
of all the
objects in the current set. If a single object is in the set, the
500×500 pixel block from the survey containing the center
of the object is displayed.
The survey is stored in the CD-ROM juke box; run
Set the gamma for converting plates to images. Default is –1.0.
Negative values display white stars, positive black.
The images look best on displays with depth 8 or greater.
EXAMPLES
Plot the Messier objects and naked-eye stars in Orion.
ori keep m <6 plot nogrid
Draw a finder chart for Uranus:
uranus expand 5 plot
Show a partial lunar eclipse:
astro -d 2000 07 16 12 45 moon add shadow expand 2 plot
Draw a map of the Pleiades.
"alcyone" expand 1 plot
Show a pretty galaxy.
ngc1300 plate 10'
FILES
SOURCE
SEE
The data was provided by the Astronomical Data Center at the NASA Goddard Space Flight Center, except for NGC2000.0, which is Copyright © 1988, Sky Publishing Corporation, used (but not distributed) by permission. The Digitized Sky Survey, 102 CD-ROMs, is not distributed with the system.