SKYMAP 1. Introduction
skymap is an interactive astronomical display program which draws a
map of the sky on any Tektronix-compatible graphics terminal, such as xterm.
Maps can be made in several coordinate systems using several projections.
Maps can be printed to any hard-copy device which supports Tektronix graphics
code. Maximum resolution is defined by the Tektronix coordinate system of 4096
horizontal by 3128 verical points.
Creation of finder charts is the most common use of skymap. The ability to
plot at a particular plate scale, such as that of the Palomar Sky Survey, is
particularly useful. The map can be centered on a specific catalog object and
include up to two catalogs plus HST Guide Stars. All-sky maps can also be
produced to show large structures or the position of a catalog in the big
picture. All of the IRAS plate projections are included so objects can be
plotted against contoured IR sky flux. Catalog objects may be identified by
plotting a catalog over an image.
Star catalogs, planet positions, and/or images can be plotted over the
coordinate grid. The Yale Bright Star , IRAS Point Source, SAO, and PPM
catalogs are available in a compact binary table format. The HST Guide Star
Catalog can be read directly from the CDROMs. Additional catalogs can be read
from files in a simple ASCII format. Planetary positions from 1950 to 2000 are
available from the JPL ephemerides, and additional solar system ephemerides
can be added easily. Any FITS image can be displayed as halftones or
Almost everything in the program is parameterized; the map format can be
modified to fit the user's requirements, and there are many possibilities for
plotting information over images or other spatial information. Character size
and font complexity may be set for several different types of map labels, and
the coordinate grids may be adjusted to the user's desire. All parameters are
stored in an ASCII file which may be modfied and viewed outside of skymap.