From Apollo 12 Mission
The camera equipment carried by Apollo 12 consisted of one 70-millimeter Hasselblad EL camera, two Hasselblad data cameras, two 16-millimeter Maurer data acquisition cameras, one 35-millimeter lunar surface close-up stereoscopic camera, and a four-camera, multispectral S-158 experiment.
From Apollo 12 Mission; Four-Camera
Four-Camera, Lunar Multispectral S-158 Experiment. The lunar multispectral camera (LMC) experiment used four Hasselblad EL cameras. The objectives of the experiment were (1) to photograph lunar surface color variations for geologic mapping, (2) to correlate photographs with spectral reflectance of returned samples for compositon determination, (3) to photograph potential lunar landing sties, and (4) to make comparative studies of lunar reflectance variation and wavelengths. (A similar experiment was flown as the SO-65 Earth multispectral photography experiment on Apollo 9.)
The four cameras used had the same parameters, settings, and ranges as the Hasselblad EL camera with the 80-millimeter lens. The cameras were mounted in a ring bracket perpendicular to the command module hatch window ±5° from nadir, 57.5° pitched up from the X axis. The shutters were automatically tripped by an intervalometer at 20-second intervals to obtain vertical strip photography.
From Apollo 12 Lunar Photography (NSSDC ID NO. 69-099A-01) also marked Data Users' Note NSSDC 70-0:
Four-Camera, Lunar Multispectral S-158 Experiment. The lunar multispectral camera (LMC) experiment used four Hasselblad EL cameras. The objectives of the experiment were:
- to photograph lunar surface color variations for geologic mapping,
- to correlate photographs with spectral reflectance of returned samples for composition determination,
- to photograph potential lunar landing sites, and
- to make comparative studies of lunar reflectance variation and wavelengths.
(A similar experiment was flown as teh SO-65 Earth multispectral photography experiment on Apollo 9.)
The four cameras used had the same parameters, settings, and ranges as teh Hasselblad EL camera with the 80-mm lens. The cameras were mounted in a ring bracket perpendicular to the command module hatch window +/- 5° from nadir, such that they were aimed and operated simultaneously. Camera alignment was 57.5° pitched up from the X axis. The shutters were automatically tripped by an intervalometer at 20-second intervals to obtain vertical strip photography. The film/filter combinations for the cameras were:
Film Filter
Camera 1 B&W 3401 Photar 47B (blue)
Camera 2 B&W 3401 Photar 29 (red)
Camera 3 B&W 3401 Wratten 58 (green)
Camera 4 IRBW SO-246 Photar 87C (black)
From Apollo Image Atlas, 70mm Hasselblad Image Catalog, Apollo 9
The Apollo 9 mission cattied six 70MM cameras. Two individual cameras and a block of four cameras that made up the Lunar Multispectral Experiment. There were a total of 1373 exposures made with 2-4 images produced for each of the 159 exposures on the multispectral experiment. The number of images on 11 magazines of film was; 318 images on black & white film, 787 on color film, and 267 on infrared film.
which is followed by a list of magazines.
Question: What did the Apollo 12 multispectral Four-Camera system actually look like? Are there photos of it, how it was mounted and used during orbit?
"bonus points": what was the purpose of the "black" filter on Camera 4?