Harold Corwin

IC 4136 may be NGC 4942, IC 4156 may be NGC 4948; and IC 4209 and IC 4212. Something has gone amiss on Harvard plate A3776. It is a one-hour exposure plate, and Stewart found four nebulae on it, all "eeF, cS" or "eF, eS." None of his positions matches any of the galaxies in the area, but fortunately, he gives position angles for three of the four objects he found. Those do allow us to tentatively match three of the galaxies to his objects: IC 4156 could be NGC 4948, and IC 4209 and IC 4212 are probably the galaxies listed in the table.

Also, his first two objects, IC 4136 and IC 4156, apparently share the same strange position error: about +5 seconds in RA, and +1d 40 arcmin in declination. When that offset is applied to Stewart's positions, the objects he probably saw turn out to be NGC 4942 and NGC 4948, respectively.

Stewart gives a position for a fifth object on the plate: NGC 4995 at 13 07 04, -07 34.0 (1950), within his nominal error of the correct position (he has an interesting note for this: "! S ring neb. with * at centre [sic]).

The four IC objects clearly should be checked on the original plate.

In the time since I wrote all that, I have wondered if Stewart had his plate somehow rotated so that his positions would be off as he read them with his overlay. However, if that was so, how did he align his overlay at all? I presume he used BD charts. In any event, the whole plate has somehow had mistaken positions read off it by Stewart.

― IC Notes by Harold Corwin

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