scat.1 (8927B)
1 .TH SCAT 1 2 .SH NAME 3 scat \- sky catalogue and Digitized Sky Survey 4 .SH SYNOPSIS 5 .B scat 6 .SH DESCRIPTION 7 .I Scat 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 13 .MR astro (1) 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. 18 .PP 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 25 in the set, 26 .I scat 27 prints how many objects are in the set; otherwise it 28 prints the objects' 29 descriptions or cross-index listings (suitable for input to 30 .IR scat ). 31 An item is in one of the following formats: 32 .TP 33 .B ngc1234 34 Number 1234 in the New General Catalogue of 35 Nonstellar Objects, NGC2000.0. 36 The output identifies the type 37 .RB( Gx =galaxy, 38 .BR Pl =planetary 39 nebula, 40 .BR OC =open 41 cluster, 42 .BR Gb =globular 43 cluster, 44 .BR Nb =bright 45 nebula, 46 .BR C+N =cluster 47 associated with nebulosity, 48 .BR Ast =asterism, 49 .BR Kt =knot 50 or nebulous region in a galaxy, 51 .BR *** =triple 52 star, 53 .BR D* =double 54 star, 55 .BR ? =uncertain, 56 .BR - =nonexistent, 57 .BR PD =plate 58 defect, and 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. 62 .TP 63 .B ic1234 64 Like NGC references, but from the Index Catalog. 65 .TP 66 .B sao12345 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 70 class, and HD number. 71 .TP 72 .B m4 73 Catalog number 4 in Messier's catalog. 74 The output is the NGC number. 75 .TP 76 .B abell1701 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. 85 .TP 86 .B planetarynebula 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. 89 .TP 90 \fL"α umi"\fP 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. 96 .BR alpha . 97 Constellation names must be the three-letter abbreviations. 98 The output 99 is the SAO number. 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. 102 .TP 103 .B 12h34m -16 104 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. 111 .TP 112 .B umi 113 All the patches in the named constellation. 114 .TP 115 .B mars 116 The planets are identified by their names. 117 The names 118 .B shadow 119 and 120 .B comet 121 refer to the earth's penumbra at lunar distance and the comet installed in the current 122 .MR astro (1) . 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 125 .BR astro . 126 The positions are current at the start of 127 .IR scat 's 128 execution; see the 129 .B astro 130 command in the next section for more information. 131 .PP 132 The commands are: 133 .TF print 134 .TP 135 .BI add " item" 136 Add the named item to the set. 137 .TP 138 .BI keep " class ..." 139 Flatten the set and cull it, keeping only the specified classes. 140 The classes may be specific NGC types, 141 all stars 142 .RB ( sao ), 143 all NGC objects 144 .RB ( ngc ), 145 all M objects 146 .RB ( m ), 147 all Abell clusters 148 .RB ( abell ), 149 or a specified brightness range. 150 Brightness ranges are specified by a leading 151 .B > 152 or 153 .B < 154 followed by a magnitude. 155 Remember that brighter objects have lesser magnitudes. 156 .TP 157 .BI drop " class ..." 158 Complement to 159 .BR keep . 160 .TP 161 .BI flat 162 Some items such as patches represents sets of items. 163 .I Flat 164 flattens the set so 165 .I scat 166 holds all the information available for the objects in the set. 167 .TP 168 .BI print 169 Print the contents of the set. If the information seems meager, try 170 flattening the set. 171 .TP 172 .BI expand " n" 173 Flatten the set, 174 expand the area of the sky covered by the set to be 175 .I n 176 degrees wider, and collect all the objects in that area. 177 If 178 .I n 179 is zero, 180 .I expand 181 collects all objects in the patches that cover the current set. 182 .TP 183 .BI astro " option" 184 Run 185 .MR astro (1) 186 with the specified 187 .I options 188 (to which will be appended 189 .BR -p ), 190 to discover the positions of the planets. 191 .BR Astro 's 192 .B -d 193 and 194 .B -l 195 options can be used to set the time and place; by default, it's right now at the coordinates in 196 .BR /lib/sky/here . 197 Running 198 .B astro 199 does not change the positions of planets already in the display set, 200 so 201 .B astro 202 may be run multiple times, executing e.g. 203 .B "add mars" 204 each time, to plot a series of planetary positions. 205 .TP 206 .BI plot " option" 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, 215 .I scat 216 does not have the information necessary to show the correct orientation for galaxies. 217 .IP 218 The option 219 .B nogrid 220 suppresses the lines of declination and right ascension. 221 By default, 222 .I scat 223 labels NGC objects, Abell clusters, and bright stars; option 224 .B nolabel 225 suppresses these while 226 .B alllabel 227 labels stars with their SAO number as well. 228 The default size is 512×512; options 229 .B dx 230 .I n 231 and 232 .BR dy 233 .I n 234 set the 235 .I x 236 and 237 .I y 238 extent. 239 The option 240 .B zenithup 241 orients the map so it appears as it would in the sky at the time and 242 location used by the 243 .B astro 244 command 245 .RI ( q.v. ). 246 .IP 247 The output is designed to look best on an LCD display. 248 CRTs have trouble with the thin, grey lines and dim stars. 249 The option 250 .B nogrey 251 uses white instead of grey for these details, improving visibility 252 at the cost of legibility when plotting on CRTs. 253 .TP 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 263 of all the 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 268 .B 9fs 269 .B juke 270 before running 271 .IR scat . 272 .TP 273 .BI gamma " value" 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. 277 .I Scat 278 does not change the hardware color map, which 279 should be set externally to a grey scale; try the command 280 .B getmap gamma 281 (see 282 .IR getmap (9.1)) 283 on an 8-bit color-mapped display. 284 .PD 285 .SH EXAMPLES 286 Plot the Messier objects and naked-eye stars in Orion. 287 .EX 288 ori 289 keep m <6 290 plot nogrid 291 .EE 292 .PP 293 Draw a finder chart for Uranus: 294 .EX 295 uranus 296 expand 5 297 plot 298 .EE 299 .PP 300 Show a partial lunar eclipse: 301 .EX 302 astro -d 303 2000 07 16 12 45 304 moon 305 add shadow 306 expand 2 307 plot 308 .EE 309 .PP 310 Draw a map of the Pleiades. 311 .EX 312 "alcyone" 313 expand 1 314 plot 315 .EE 316 .\" .PP 317 .\" Show a pretty galaxy. 318 .\" .EX 319 .\" ngc1300 320 .\" plate 10' 321 .\" .EE 322 .SH FILES 323 .B \*9/sky/*.scat 324 .SH SOURCE 325 .B \*9/src/cmd/scat 326 .SH SEE ALSO 327 .MR astro (1) 328 .br 329 .B \*9/sky/constelnames\ \ 330 the three-letter abbreviations of the constellation names. 331 .PP 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.