When the A3P went through many gradual improvements, it gave way to the models 512 and 1024 in 1973. It has been a question to what exactly the changes are between the A-4, 512 (image) and 1024. All three models utilise a Xenon arc lamp of 75 W for the star projection. The number of stars varies from 1350 through 4000. As other models, it allows the standard motions (diurnal, annual and precession) and can be adjusted to any geographical latitude. Grids are also implemented: equator, ecliptic and the meridian scale. The keyboard at the control desk is illuminated, and other media can be patched in, e.g. a video projector or acoustic devices. The Spitz-1024 is amended by some nebulous objects like the Beehive Cluster, Andromeda Galaxy and the Magellanic Clouds. Both versions enable manual presentations only.