Harold Corwin

IC 3009 is probably a defect on Schwassmann's plate. There is nothing near his position bright enough to match his description ("pB, cS, fig? dist"). I also think that the "fig? dist" is telling -- it reads like a description of a plate defect.

Arnold Schwassmann, unlike his Heidelberg colleague Max Wolf, worked on a plate taken with a 6-inch astrographic refractor. For the IC, his contribution comes from a single massive paper in the first volume of the Publications of the Konigstuhl-Heidelberg Observatory of 1902, sub-titled "Konigstuhl-Nebelliste No. 2" (the other lists merged into the IC are 1 and 4-7, all by Max Wolf. List No. 3, also by Wolf, has about 1500 nebulous objects in the area of the Coma Cluster).

In his paper, Schwassmann developed techniques of plate reduction -- intended to convert x-y measurements on photographic plates to equatorial coordinates -- to find accurate positions of objects. As a "test" case, he used a plate taken by Wolf on 15 April 1895 centered near 20 Virginis. The plate covered an area of 12.0 x 8.2 degrees, and recorded 301 objects that Schwassmann took to be nebulous. As with many of the other pioneering efforts in photography, many stars and a few defects ended up in this list of nebulae.

When Wayne Johnson requested copies of the plates from Heidelberg, he received only those from Wolf's 3rd through 8th lists along with the information that the other plates could not be found in the archives. So, I do not have a copy of the plate that Schwassmann used for his survey of the Virgo Cluster.

― IC Notes by Harold Corwin

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