3 scat \- sky catalogue and Digitized Sky Survey
8 looks up items in catalogues of objects
9 outside the solar system
10 and implements database-like manipulations
11 on sets of such objects.
12 It also provides an interface to
14 to plot the locations of solar system objects.
15 Finally, it displays images from the
16 Space Telescope Science Institute's
17 Digitized Sky Survey, keyed to the catalogues.
19 Items are read, one per line, from the standard input
20 and looked up in the catalogs.
21 Input is case-insensitive.
22 The result of the lookup becomes the set of objects available
23 to the database commands.
24 After each lookup or command, if more than two objects are
27 prints how many objects are in the set; otherwise it
29 descriptions or cross-index listings (suitable for input to
31 An item is in one of the following formats:
34 Number 1234 in the New General Catalogue of
35 Nonstellar Objects, NGC2000.0.
36 The output identifies the type
47 associated with nebulosity,
50 or nebulous region in a galaxy,
59 (blank)=unverified or unknown),
60 its position in 2000.0 coordinates,
61 its size in minutes of arc, a brief description, and popular names.
64 Like NGC references, but from the Index Catalog.
67 Number 12345 in the Smithsonian Astrophysical Star Catalogue.
68 Output identifies the visual and photographic magnitudes,
69 2000.0 coordinates, proper motion, spectral type, multiplicity and variability
73 Catalog number 4 in Messier's catalog.
74 The output is the NGC number.
77 Catalog number 1701 in the Abell and Zwicky
78 catalog of clusters of galaxies.
79 Output identifies the magnitude of the tenth brightest member of the cluster,
80 radius of the cluster in degrees, its distance in megaparsecs,
81 2000.0 coordinates, galactic latitude and longitude,
82 magnitude range of the cluster (the `distance group'),
83 number of members (the `richness group'), population
84 per square degree, and popular names.
87 The set of NGC objects of the specified type.
88 The type may be a compact NGC code or a full name, as above, with no blank.
91 Names are provided in double quotes.
92 Known names are the Greek
93 letter designations, proper names such as Betelgeuse, bright variable stars,
94 and some proper names of stars, NGC objects, and Abell clusters.
95 Greek letters may be spelled out, e.g.
97 Constellation names must be the three-letter abbreviations.
100 For non-Greek names, catalog numbers and names are listed for all objects with
101 names for which the given name is a prefix.
104 Coordinates in the sky are translated to the nearest `patch',
105 approximately one square degree of sky.
106 The output is the coordinates identifying the patch,
107 the constellations touching the patch, and the Abell, NGC, and SAO
108 objects in the patch.
109 The program prints sky positions in several formats corresponding
110 to different precisions; any output format is understood as input.
113 All the patches in the named constellation.
116 The planets are identified by their names.
121 refer to the earth's penumbra at lunar distance and the comet installed in the current
123 The output is the planet's name, right ascension and declination, azimuth and altitude, and phase
124 for the moon and sun, as shown by
126 The positions are current at the start of
130 command in the next section for more information.
136 Add the named item to the set.
138 .BI keep " class ..."
139 Flatten the set and cull it, keeping only the specified classes.
140 The classes may be specific NGC types,
149 or a specified brightness range.
150 Brightness ranges are specified by a leading
154 followed by a magnitude.
155 Remember that brighter objects have lesser magnitudes.
157 .BI drop " class ..."
162 Some items such as patches represents sets of items.
166 holds all the information available for the objects in the set.
169 Print the contents of the set. If the information seems meager, try
174 expand the area of the sky covered by the set to be
176 degrees wider, and collect all the objects in that area.
181 collects all objects in the patches that cover the current set.
188 (to which will be appended
190 to discover the positions of the planets.
195 options can be used to set the time and place; by default, it's right now at the coordinates in
199 does not change the positions of planets already in the display set,
202 may be run multiple times, executing e.g.
204 each time, to plot a series of planetary positions.
207 Expand and plot the set in a new window on the screen.
208 Symbols for NGC objects are as in Sky Atlas 2000.0, except that open clusters
209 are shown as stippled disks rather than circles.
210 Abell clusters are plotted as a triangle of ellipses.
211 The planets are drawn as disks of representative color with the first letter of the name
212 in the disk (lower case for inferior planets; upper case for superior);
213 the sun, moon, and earth's shadow are unlabeled disks.
214 Objects larger than a few pixels are plotted to scale; however,
216 does not have the information necessary to show the correct orientation for galaxies.
220 suppresses the lines of declination and right ascension.
223 labels NGC objects, Abell clusters, and bright stars; option
225 suppresses these while
227 labels stars with their SAO number as well.
228 The default size is 512×512; options
241 orients the map so it appears as it would in the sky at the time and
247 The output is designed to look best on an LCD display.
248 CRTs have trouble with the thin, grey lines and dim stars.
251 uses white instead of grey for these details, improving visibility
252 at the cost of legibility when plotting on CRTs.
254 .B "plate \f1[[\f2ra dec\f1] \f2rasize\f1 [\f2decsize\f1]]"
255 Display the section of the Digitized Sky Survey (plate scale
256 approximately 1.7 arcseconds per pixel) centered on the
257 given right ascension and declination or, if no position is specified, the
258 current set of objects. The maximum area that will be displayed
259 is one degree on a side. The horizontal and vertical sizes may
260 be specified in the usual notation for angles.
261 If the second size is omitted, a square region is displayed.
262 If no size is specified, the size is sufficient to display the centers
264 objects in the current set. If a single object is in the set, the
265 500×500 pixel block from the survey containing the center
266 of the object is displayed.
267 The survey is stored in the CD-ROM juke box; run
274 Set the gamma for converting plates to images. Default is \-1.0.
275 Negative values display white stars, positive black.
276 The images look best on displays with depth 8 or greater.
278 does not change the hardware color map, which
279 should be set externally to a grey scale; try the command
283 on an 8-bit color-mapped display.
286 Plot the Messier objects and naked-eye stars in Orion.
293 Draw a finder chart for Uranus:
300 Show a partial lunar eclipse:
310 Draw a map of the Pleiades.
317 .\" Show a pretty galaxy.
329 .B \*9/sky/constelnames\ \
330 the three-letter abbreviations of the constellation names.
332 The data was provided by the Astronomical Data Center at the NASA Goddard
333 Space Flight Center, except for NGC2000.0, which is Copyright © 1988, Sky
334 Publishing Corporation, used (but not distributed) by permission. The Digitized Sky Survey, 102
335 CD-ROMs, is not distributed with the system.
