Authentic Science Fiction Monthly, No. 66 — page 44: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

AUTHENTIC SCIENCE FICTION but, owing to the distance of the observer from the screen, these discs are not objection- able. The stars of the lowest magnitudes may have images of as little as one sixteenth of an inch diameter. A gravity- controlled occulting device, mounted in front of each projector, gradually reduces the light as the lens approaches the horizon and simulates the effects of increasing atmos- pheric absorption. The Milky Way is projected by two drum-type projectors, one at each side of each star globe. This feature of the PROJECTOR CAGE FOR MARS AND JUPITER 43 night sky is non-uniform both in width and brightness, yet its presentation in the planet- arium is most realistic. A drawing was first made by stippling a negative. This negative was then photo- graphed on a curved film. Occulting for the part of the Milky Way beneath the hori- zon is done by half-filling each cylinder carrying the film with mercury. Further sets of projectors give reference either to the celestial equator—declination and right ascension—or to the ecliptic—celestial latitude and conmicloooks.com