Glass positive:- "Horses head" dark Nebula in Orion
- Made:
- 1920 in Mount Wilson
- photographer:
- John C. Duncan
- maker:
- Hinton and Co.
Glass positive:- "Horses head" dark Nebula in Orion, dark nebulosity south of Zeta (G) Orionis, by John C. Duncan, Mount Wilson Observatory, 1920, November 13, 100-inch reflector, focal length, 42ft, exposure, 3 hours, 14" x 17"
