Harold Corwin

IC 1925 is probably a plate defect. It is listed as the first of a pair of nebulae, but there is only one object (IC 1929) on the modern plates. There is a faint possibility that it is identical to I1929 -- the descriptions are nearly the same, "E np to sf, stell" for IC 1925 and "E np to sf" for IC 1929 -- so that is given as an option in the table.

Since it was found on the same plate as IC 1929, however, I think it is unlikely that the two objects are identical.

Courtney Seligman wrote about these two in July 2021, noting that Wolfgang Steinicke has them as identical. This goaded me into looking at the two again. Here, from my note to Courtney, is what I found:

Looking at this again, I think that Wolfgang is correct, but perhaps not for the reason you suggested [the same object was measured twice on the same plate]. Though both objects are said to be on plate 3339 (centered at 03 31, -52.5 for 1900), plate 3346 (03 24, -51.0) largely overlaps the earlier plate. The text in Harvard Annals, Vol 60, says, "Dots in this [final] column [of Table III] indicate that the region is covered by another plate. Since the plates overlap, and the objects are only given once, the number given in the last column is that of the objects whose positions were determined from the plate in question, and not the complete number which may appear on the plate." This suggests that all the positions in this area were determined on plate 3339 and, given that no additional nebulae, were found on plate 3346 -- with dots in the final column -- this conjecture is reinforced.

However, the positions for IC 1925 = HN 188 (03 22.3, -51 37 for 1900) and IC 1929 = HN 191 (03 22.5, -51 37) are within 1-sigma of being identical. The descriptions are also telling, of course: IC 1925: "E np to sf, stell.", IC 1929: "E np to sf."

So, given all this, I think that the galaxy was measured on both plates, and that because of a bookkeeping error -- perhaps based on the slightly different positions -- the object ended up in the final list with two entries. I'm not sure about this, of course, but it makes a plausible story, perhaps a bit more likely than your idea that Stewart measured the object twice on the same plate. But who knows? All this is conjecture.

Given that I now think the equality of the two objects is likely, I've changed the double queries in the main table to single colons. Wolfgang and Courtney are probably right.

― IC Notes by Harold Corwin

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