Robert C. Moler

Calculates Julian date, sidereal time; rise/set times; altitude/azimuth; procession of celestial objects; and more. 16K.

Draws normal and barred spiral galaxies from input parameters. Galaxies may have variable orientation from face-on to edge-on. Choice of two spiral algorithms. 16K.

Astronomical demonstration program for educators. Draws elliptical orbit shapes based on eccentricity. Also calculates and produces animated display of orbital motion. 16K.

Calculates and displays positions of the planets around the sun for a date or series of dates. Can plot planet distances to scale and include a comet. 16K.

Uses the high resolution capabilities of the ZX printer to plot the positions of the planets in their orbits. Menu driven with 4 plotting options. Orbits are delineated and planets are plotted with their astronomical symbols. 16K.

Graphically demonstrates effects of relativistic velocities on length of a spacecraft plus time dilation effects. Demonstrates the “twin paradox” on trips to Alpha Centauri and the Andromeda Galaxy.