Spectrophotometric Studies of Gaseous Nebulae. I. The Double-Ring Planetary NGC 7009.
Abstract
Spectrophotometric data obtained with a photoelectric spectrum scanner at Mount Wilson Observatory in t956 and Mount Stromlo Observatory in 1961 are combined with photographic observations obtained with coud spectrographs at Mount Wilson and Lick Observatories to obtain line intensities and identifications in the spectral region X 31O() 4960. Lines as weak as 0.02 on the scale I (HP) = 100 are measured on the longest exposure.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1964
- DOI:
- 10.1086/147848
- Bibcode:
- 1964ApJ...139.1074A