The purpose of this film is to show how the Moon passes through the Earth's shadow during a typical total lunar eclipse.
The film shows the Moon entering the Earth's shadow at the upper right-hand corner of the screen. This occurred at 12:53 a.m. and marks the start of the eclipse. The Moon then slowly disappears from view and, at 2:04 a.m., enters the Earth's shadow entirely. At this point, the eclipse is said to be total. Note that the Moon is not completely black but has a distinct bricked colour. This colour is due to the refraction or bending of sunlight by the atmosphere of the Earth. The blue rays in sunlight are blocked by the Earth's atmosphere but the red rays penetrate and are bent around the Earth so that they ultimately fall on the Moon. At 3:27 a.m. the moon begins to emerge from the Earth's shadow as shown at the lower left-hand corner of the screen. At 4:38 a.m., the Moon is fully visible again and the eclipse is over.
High-speed Ektachrome was used to make this film. Outside of totality, one frame was exposed every four seconds at 1/60 sec. and f:ll. During totality, the film was advanced at the rate of one frame every five seconds and each frame received an exposure of 4 sec. at f:4.5.
Script is copyright Reuters Limited. All rights reserved
Background: The purpose of this film is to show how the Moon passes through the Earth's shadow during a typical total lunar eclipse.
The eclipse chosen for observation was one which occurred on the morning of February 10, 1971. To obtain the necessary photographs, the U. S. Navy Observatory mounted a 16mm movie camera with a 300mm lens on an astronomical telescope and pointed along the axis of the Earth's shadow. The telescope was sidereally driven to compensate for the Earth's rotation.