A Polarigraphic Study of the Reflection Nebula NGC 6729.

The variable nebula NGC 6729 was photographed through a sheet of Polaroid and its polarization determined. Visual examination of the plates indicated that polarization was definitely present. Reduc- tion of microphotometer traces over the nebulosity yielded a mean maximum of about 15 per cent. There is an indication that the nebula close to T CrA may derive a little of its light from that star as well as from R CrA. To the southwest of R CrA is located a wisp of nebulosity extending away from two brighter spots, one of which is surrounded by a faint ring. The wisp and bright spots show polarization, the latter having a mean of 11 per cent and a maximum of about 15 per cent. The apparent radial polarization in NGC 6729 and the wisp of nebulosity to its southwest, with R CrA as center, is everywhere between zero and 35 per cent, and for the most part it is less than 20 per cent