Harold Corwin

IC 1589 is a double star, probably the one at the position given in the main table. It is some distance off Swift's place, but his positions determined after the move to Lowe Observatory are notoriously bad. His description clearly matches that of a double star seen through some rather thick layers of air. This is plausible as the object has a zenith distance of almost 70 degrees from the latitude of Echo Mountain (+34 deg).

This is one of the few cases where Swift's descriptions vary among his published lists. This object appears in four different journals, three in Swift's third list of nebulae found at Lowe (MN 57, 631; PASP 9, 223; and Pop. Astron. 5, 426, all 1897), and in the collected list in AN 3517, 1898. In the short lists, he gives the description as "pB ["fB" in MN], eeS, E; with 132 and 200 [only 200 in Pop. Astron.] looks like a nebulous D Uranus"; while the AN "Catalogue No. 11 of Nebulae", the description reads "eF, eeS, R; ..." The position is given the same in the three short lists (00 46 45, -35 00 43; 1900), while in the longer AN list, it appears as 00 46 45, -35 00.5. In principle, we should probably take the position from the later AN list, but I've decided to include both in the big position table.

See IC 1740 for a similar double star that Swift found just over a month later in September of 1897, and NGC 3260 for more on the double objects that interested him so much.

― IC Notes by Harold Corwin

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