Harold Corwin

IC 4629 is probably a plate defect. Stewart gives a relatively detailed description, "vF, vS, eE at 75 degrees, RA may be [16] 51.0 [1900.0], susp," but there is nothing at either of his positions that matches this. Since the plate is a short-exposure, one-hour plate and Stewart had no other of the area, the most likely hypothesis is a plate defect.

Ralph Dowdee, using the telescopes of SLOOH.com, has several images of the area, none of which show anything at the nominal position of IC 4629. Ralph's images did show the dark nebula LDN 122, located at 16 52 25, -16 40.0 about a minute of time preceding the nominal position for IC 4629.

See also IC 4622, another missing object that Stewart found on the same plate. In that case, however, he did not mark the object "susp." Was this an oversight, or did he actually have another plate that overlapped the position for IC 4622? We need to look at the original plate.

― IC Notes by Harold Corwin

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