Harold Corwin

IC 2630 is a star, confirmed on a print of the original plate. All of Wolf's marks have been removed from this plate from which his seventh list of new nebulae was compiled, so I've centered up his position in a DSS field, then checked the print against the DSS. That points unmistakeably at the star.

By the way, I use the word "confirmed" with this plate rather than "verified" as I have with his other plates which still bear his marks pointing at the "nebulae" he found. This is simply to indicate that the marks are indeed missing.

Steve Gottlieb has pulled accurate positions out of the USNO-A1.0 star catalogue for these seventh list objects, where they exist, of course. These are usually good enough to accurately pin down the object that Wolf noted. Once in a while, however, the stars with "significant" proper motion -- something like 50 milliarcseconds per year or larger -- can now be well off Wolf's positions when they are simply precessed from equinox 1875 to 2000. I've often indicated these stars in the notes, but since Wolf's positions have standard deviations on the order of 4-5 arcseconds, even "large" proper motions are sometimes lost in the errors.

I've also noticed that parts of the print are subtly out of focus. As it is a contact print, I suspect that it was not tightly pressed against the original plate when it was made. There is, of course, some coma as well in the images far from the plate center, but Wolf must have recognized this as he searched for new nebulae only in the central six degrees of the eight- by seven-degree field captured on the 30- by 23.5-cm plate.

― IC Notes by Harold Corwin

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