SKYMAP Example 4: Center Field from Catalog

For Postscript, click on this map.

The easiest way to use skymap to plot finder charts for a series of objects is to put the object positions in a catalog and plot from that catalog. That way you don't have to worry about mistyping, and the source of the position will be in the heading. It is also possible to list the positions of the plotted Guide Stars (or stars from any other displayed catalog) in a separate file.

Here is the output map, with the center marked by an open cross. If the star was in the Guide Star Catalog, it would be visible in the center of the cross-hairs.

Here is a subset of a catalog of stars, stored in file mkp.so, which were possibly occulted by Pluto in the SAO TDC ASCII catalog format.

mkp
Pluto Mink,Klemola,Elliot + Mink,Klemola,Buie 1984-1999
 1 14.3005900 +2.520984 15.93
 2 14.2111883 +3.202119 12.83
 3 14.3825165 +2.261549 15.77
 4 14.3444956 +2.505065 14.87
 5 14.3008198 +2.573106 15.06
 6 14.3006754 +2.230340 15.27
 7 14.3146971 +2.032004 15.71
 8 14.4936865 +0.571949 12.20
 9 14.5836697 -0.037662 14.82

The following sets up a 10-arcminute square field, centered on the first star in the mkp.so catalog. The Guide Star Catalog objects which are found are marked on the map and a list of position, magnitude, type (0=stars, 3=nonstars), and the number of plate positions for each object is written to the file mkp1.gsc.

$ skymap

SKYMAP 3.2: Display data on sky (Doug Mink, CfA, June 1995)

SKYMAP? Guide Stars:  C>har L>ab D>ir N>ame M>ag ?>menu : S
        Star list file (-=none) = mkp1.gsc

SKYMAP? Guide Stars:  C>har L>ab D>ir N>ame M>ag ?>menu :  =

SKYMAP? V center star: S>tar F>ile D>ir T>ime N>ame ?>menu : ?
        C  Character with which to mark center of map
        D  Pathname of directory containing source catalog
        F  Name of file containing source catalog
        J  Catalog in J2000 or B1950
        L  Label for center source
        N  Name of source catalog
        P  Add proper motion for source
        I  Read object name or date from catalog
        S  Source on which to center map
        =  List values of center source parameters
        ?  List all possible menu selections

SKYMAP? V center star: S>tar F>ile D>ir T>ime N>ame ?>menu : S
        Source on which to center map (0=none) = 1

SKYMAP? V center star: S>tar F>ile D>ir T>ime N>ame ?>menu : F
        File name for source catalog (-=none) = mkp.so
        Catalog binary rather than ASCII (y or n) : n

SKYMAP? V center star: S>tar F>ile D>ir T>ime N>ame ?>menu : C
        Character -1=none 0=closed,1=open,2=constant circles
          3=full,4=half cross, 5=full,6=half X = 3
        Radius of cross in display units = 40
        Radius of gap to cross in display units = 20

SKYMAP? V center star: S>tar F>ile D>ir T>ime N>ame ?>menu :  =

SKYMAP? Map:  P>roj S>ys G>rid C>enter H>alf-width ?>menu : H
        Half-height (Dec) (dd.mmss) = .05
        Half-width in RA (hh.mmss, 0=square) = 0

SKYMAP? Map:  P>roj S>ys G>rid C>enter H>alf-width ?>menu :  =

SKYMAP? Plot sky map
    1/   1     8/ 2255 sources from /gsc/vol1/GSC/N0000/0328.GSC
           1 region:            8 /        2255 found

SKYMAP? Quit
$

Here is the list of stars in the field written to mkp1.gsc. The catalog number is given as ., follwed by the right ascension in hours, minutes and seconds, and the declination in degrees, minutes, and seconds. The magnitude is a plate magnitude, approximating V from the Northern Hemisphere PAL-V plates and B from the Southern Hemisphere SERC-J plates. The following column lists the object type code (0=star, 1=nonstar, 5=plate artifact), and the final column is the number of plate positions which were combined to create the printed position. The original J2000 position from the catalog was converted to B1950 using the method of Yallop, Hohenkerk, Smith, Kaplan, Hughes, and Seidelman (1989), Astron. J. 97, pages 274-279, as implemented by P.T. Wallace in the STARLINK library.

HST Guide Star Catalog (GSC) B1950
 328.0028   14  30  13.424     2  55  59.98  14.66 0 2
 328.0042   14  29  55.145     2  52  06.04  14.23 0 2
 328.0050   14  30  11.821     2  49  25.54  11.34 0 2
 328.0057   14  30  07.893     2  54  38.29  14.12 0 2
 328.0064   14  30  05.999     2  56  35.48  13.27 0 2
 328.0077   14  30  05.079     2  52  07.54  13.07 0 2
 328.1223   14  30  21.311     2  51  47.48  14.21 0 1

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