NGC 729

History and Accurate Positions for the NGC/IC Objects (Corwin 2004)

NGC 729 = NGC 727. JH describes N729 = h2446 as "eeeF, S, R. RA only rudely taken by a star, being out of the field." He recorded it only once in Sweep 803.

Much earlier, however, in Sweep 486, he found another nebula in the area, N727 = h 2445. His description of that reads "F, S, R, bM, 15 arcsec." He then adds (in italics enclosed by square brackets, flagging a note added during the preparation of the Cape Observations for publication), "It is barely possible that this and the next nebula [h2446 = N729] may be identical with Nos. 2440 [= N696] and 2441 [= N698] by a mistaken degree in PD." The relative positions -- the later object in each pair is northeast of the earlier -- as well as the descriptions [N696: "F, S, R, 15 arcsec;" N698: "vvF, S"] support the idea. I suspect that JH also had his note about the "rudely taken" RA in mind when he added his comment several years later.

However, the N696/8 pair was found in Sweep 802, and its RA is 4 min 15 sec off the N727/9 pair. This means 1 degree errors in both coordinates, rather than just in Dec as JH points out. Since the position of N729, "rudely taken" as it is, is close to that of N727, and since the two were seen on different nights, it seems more plausible to me that the observations refer to the same object. We can't dismiss JH's comment out of hand, though having both coordinates off by a degree would be unusual in his southern data.

ESO's suggestion that N729 is a double star at 01 52 01, -36 03.0 (it is ESO 354-**011) seems less probable to me. JH made many hurried observations of "new" nebulae which have turned out to be identical to objects that he has securely observed during other sweeps.

Historical observations

John Herschel (1847) Cape Observations

Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "eeeF, S, R."

Published comments

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a galaxy. Their coded description reads USB,CLOSE DB*) - Uniform surface brightness, close double star?

NGC 2000.0

The NGC 2000.0 calls it a double star.