Harold Corwin

IC 2262 is a star, verified on a print of the original plate.

Of the 154 nebulae found by Max Wolf on three plates taken with the 16-inch Bruce reflector at Heidelberg early in 1901, only a few are real galaxies. I have compared a print of one of the plates (B.137; the others are apparently missing), kindly sent to Wayne Johnson by G. Klare of Heidelberg Observatory, with the POSS1 prints covering the field. The objects included in Wolf's list are marked on the plate, presumeably by Wolf himself. These leave no doubt that most of the objects are faint stars or, sometimes, multiple stars, occasionally involving plate defects. This was the first such paper published by Wolf. Later papers seem to have a somewhat smaller -- but still large -- percentage of non-nebular entries. These are discussed as needed in these notes.

Most of the objects are right at the plate limit. Wolf was clearly pushing beyond certainty in his classification of these faint objects. Fortunately, his positions, once corrected for a small systematic error (they tend to be northeast of the true place by about 2-3 arcsec, at least for this first paper), are very good (mean errors around 2-3 arcsec) so that -- even in the absence of the photographs -- there is no way to misidentify the objects he saw as nebulous (aside from typographical errors in his tables, of course; IC 2350 is one such error).

Very few of the objects are "Not found." Those marked on the plate that I can positively identify that are also not present on POSS1 are either photographic defects or -- in a few cases -- possible asteroid trails.

Wolf's positions are quoted in the main table, along with the usual assortment of others, with the preferred position -- usually from 2MASS PSC, UCAC, or SDSS -- flagged as usual. All the stars and multiple stars are identified there, as are the "Not found's." I won't go through a big "story" for each of these objects unless one happens to be a previously known nebula that Wolf missed identifying for some reason (e.g. NGC 2643 = IC 2390; see N2643 for the short discussion); or unless I have another special reason to do so. Aside from noting the identities, and possible errors in the NGC position, there just isn't a whole lot to be said about all these stars!

Curiously, Wolf also missed a few real galaxies on the plate, too -- CGCG 089-027 is one such galaxy. Its image is indeed present on the plate -- if one knows in advance that it is there -- but is of low enough surface brightness that Wolf most likely overlooked it as a random variation in plate grain.

By the way, it has helped considerably to use DSS to examine Wolf's positions. There is almost always a faint object within a couple of standard deviations of Wolf's position. Even so, his descriptions make clear that there must have been plate defects -- or plate grain clumps -- involved, too.

― IC Notes by Harold Corwin

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