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 contours.


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.

SKYMAP manual SKYMAP home Next page