Harold Corwin

IC 4544 is one of Fleming's "stellar planetary nebulae" discovered on objective prism plates taken at one of Harvard's southern stations. It is also, as Brian Skiff pointed out to me, the "lost" Nova Nor 1893 = IL Nor = HD 137677.

"Lost" because, unfortunately, the old Harvard position falls in a rich field of very faint stars. Also, the reference to the original paper is given incorrectly in HA 60; the object is not included in the AN (volume 128, page 11) paper of 1891 (Dreyer would have included it in IC1 if it were there). The variable star guys must have kept track of it, because the positions for IL Nor given in the catalogs of novae and cataclysmic variables are pretty close (see next paragraph) to the modern ones.

Fortunately, Patrick Woudt and Brian Warner have recovered the object, and have given a finding chart for it (see their paper in astro-ph at http://arxiv.org/abs/0912.4656). Their high-speed photometry shows intra-day V-magnitude variations on the order of 0.3 mag around 18.5 to 19.0. Brian Skiff estimated the position as 15 29 23.08, -50 35 00.5 (J2000.0; 15 25 45.53, -50 24 41.8 for B1950.0) with respect to the 2MASS position for a single nearby star. Patrick Woudt, at Skiff's request, did an astrometric solution with respect to 2MASS positions for half a dozen nearby stars: 15 29 22.99, -50 35 00.4 (J2000.0; 15 25 45.44, -50 24 41.7 for B1950.0) with a formal error of less than 0.1 arcsec. These positions are (apparently coincidentally) close to, but much more accurate than the positions carried in the current catalogs of classical novae (e.g. Duerbeck, Space Science Reviews 45, 1, 1987).

All these positions are given in the main table. My thanks to Brian (Skiff) for the pointer to Woudt and (Brian) Warner's recent (2010) paper.

For the record, the Gaia DR2 position is 15 29 23.0054, -50 35 00.438 (J2000.0), with a parallax of 0.4018 mas, and proper motions of -5.392 and -4.639 mas/yr. The BP magnitude is 18.77, and RP is 17.82. The star is the eastern and fainter of the two nearly blended images seen on the DSS2R near the Gaia DR2 position which I have adopted.

― IC Notes by Harold Corwin

Drawings, descriptions, and CCD photos are copyright Andrew Cooper unless otherwise noted, no usage without permission.

A complete list of credits and sources can be found on the about page