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Document Type

Research

Abstract

To our knowledge the first time this "Bird's Nest" marking was considered as a possible ring of absorbing nebulosity was in 1910 when the senior author noticed the object and mentioned the possibility that it might be an actual ring of dark absorbing nebulosity. The ring is conspicuously evident upon every exposure of long enough duration to exhibit such markings. It is located in the "Labrador" section of the North America Nebula, right ascension 20 hours, 52 minutes, declination plus 45 degrees. Its external diameter is about thirty minutes of arc and its internal diameter about twelve minutes of arc.

Publication Date

1928

Journal Title

Proceedings of the Iowa Academy of Science

Volume

35

Issue

1

First Page

55

Last Page

67

Copyright

© Copyright 1928 by the Iowa Academy of Science, Inc.

Language

EN

File Format

application/pdf

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