NGC 741

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

NGC 741 = IC 1751. This, along with NGC 742, was discovered by William Herschel, reobserved by John Herschel, and by Lord Rosse. N741 itself is the brightest in a group of galaxies, and the positions in NGC from the Herschels are good. Furthermore, their descriptions make it clear that all saw the same two galaxies. They did not pick up any of the other objects in the area.

This leads to the puzzle of why the brighter of the two was also included in IC. True, it reappeared in Swift's 11th list of "new" nebulae (with one of his typically inaccurate positions), and was reobserved by Herbert Howe at Chamberlin Observatory in Denver. Howe provided a very good micrometric position for it which was adopted by Dreyer for the IC. I suspect that as Dreyer had come to trust Howe's positions and identifications (most of Howe's observations are of known objects), he (Dreyer) didn't bother to check the NGC to see if the galaxy had been seen previously.

More recently, the IC number has been attached in CGCG (and in other subsequent lists) to the galaxy (CGCG 413-006) just over an arcminute northwest of N741. This object is indeed brighter than many that Swift found, but his description of a 9th magnitude star "north-preceding" rather than simply "preceding" pretty well establishes the identity. It is further pinned down by Howe's measurement of the distance and direction to the star (actually a double, or perhaps a single star superposed on a galaxy) which points exactly to N741 as the object that he measured.

Historical observations

William Herschel (c.1784)

Synonyms: H II-271

Discovered in 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "Two, very close, not far from lying on a parallel to the declination. The following [NGC 742] smallest and most north."

NGC/IC Dreyer (1888, 1895, 1908)

Dreyer notes: "Observed three times by H, but he only once saw it double. The following one is very slightly south of the preceding one." The NGC calls it "pF, S, R, p of 2, pos 102 degrees."

Birr Castle/Lord Rosse

An observer using the 72-inch f/8.8 speculum telescope at Birr Castle noted "Double nebula [NGC 741 & NGC 742]; the preceding one is pB, R, bM. The following one is smaller and fainter, and lbM."

Published comments

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 13.0 mag galaxy. Their coded description reads E,R,BM,COMOR* FOSIDE.

Modern observations

Steve Coe

Steve Coe, using a 13.1" f/5.6, notes: ""NGC 741 Pretty faint, pretty small, much brighter middle, round, at 135X. A companion galaxy to the East makes this object appear elongated until a moment of good seeing splits them into two seperate galaxies."