Word: penumbra
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...total shadow that extends out into space from the night side of Earth is a slightly tapering cone. The partial shadow, or penumbra, is a slightly spreading cone. Earth did not swing directly between moon and sun last week, and the moon slid through the penumbra. Appulses of this kind are astronomical curiosities because an average of 85 occurs in a century, whereas total and partial eclipses (in which the moon passes wholly or partly through the cone of total shadow) happen almost twice as frequently. About twelve appulses in a century are, like last week's, conspicuous...
...weather conditions on Saturday evening were very favorable for witnessing the eclipse, and although the moon entered the penumbra before rising, many interesting observations were made at the Observatory and ten successful photographs were secured...