Abstract
The appearance of the expanding nebula around Nova Herculis on photographs obtained with the 100-inch reflector in 1940 was described in a previous note.1 The nebula then appeared as a small elliptical disk of uniform brightness when photographed in the light of the strong N 1 and N 2 emissions. Its surface brightness, both in the photographic and the photovisual range, was so high that the central star was lost in the light of the surrounding nebulosity. Quantitative data, given at the end of the note, indicated, however, that decreasing surface brightness of the nebula due to the expansion would make it possible to distinguish the star in the near future. The present note deals with observations of the nebula during the summer of 1942. Most of the plates during this season were taken at the Cassegrain focus of the 100-inch reflector, which offers the advantage of a large scale (1 mmziSTO). The fact that the Cassegrain arrangement can be used to full advantage only with seeing 6 or better imposed no serious restrictions since the best seeing is required anyhow to photograph details in an object barely 4 seconds of arc in diameter.
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