A peculiar object in Serpens.

This object, which appears to be a perfectly symmetrical planetary nebula, was discovered on a 75-minute Jewett Schmidt plate. A perfect halo, 17" in radius, surrounds a diffuse central image. Its position, ± 15h 15m0, δ +21° 46' (1950), l 358°, b+54° (1950), size and nucleus ( ~17 mpg, C. I. ~+ I.O) are not typical of the planetary nebulae. The halo, which is bluer than the nucleus, does not show in emission on an objective prism plate that records the central object.

As a most conservative alternative one might say that this is a new species among the "pathological" galaxies. Other ring-forming mechanisms such as a diffraction effect^1 or a gravitational lens system^2 are less probable explanations. The mass of the central object, in the latter case, would have to be of the order of 8 x 10^11 solar mass.

Since the object is unique, I suggest that a proper identification would be a worthwhile short-term project.

1.Struve, Ann. Astroph. I, 143, 1938.

2.Zwicky, Phys. Rev. 51, 290, 1937.

Harvard College Observatory,Cambridge, Mass.