IC 1613 (UGC 668, DDO 8, LEDA 3844) Dwarf Galaxy in Cetus

Located at: RA 01 hours 04 minutes 47 seconds, Dec +02 degrees 07 minutes 05 seconds

Size: 16.3' x 15.4' Magnitude: 9.9 blue Class: IB(s)m

North is up

West to the right


 8" f5 Newtonian reflector


 ST-8XME, self-guided, binned 1x1, temp -20c, camera control MaxIm DL 4.56


Lumicon Red filter, 690 minutes (69 x 10 minute subs), 12/18/19/21/2017; seeing 2.6-5.0 (6.1) FWHM per CCDStack

Processing: CCDStack 2.94.6355.18107, Photoshop CS5.1

 Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)


Finally gave up on this one as the waxing moon approached ... December weather has not been kind to imaging. We have had no rain, but have had plenty of winds (and fires), and periods of high clouds. I took 91 subs, but did not use subs over 5 arc seconds seeing. Had to work on the background, as some of the subs I kept had periods of high clouds. See the 8" version.

From the NGC / IC Project:

IC 1613 = UGC 668 = MCG +00-03-070 = Cetus system = PGC 3844

01 04 46.2 +02 07 04

V = 9.2;  Size 16.2'x14.5';  Surf Br = 15.0;  PA = 50d


48" (10/26/16): I spent a few minutes identifying OB associations in the patchy northeast section of IC 1613. At 375x I was able to pinpoint a half-dozen faint or fairly faint "knots", generally 12"-15" in diameter within a 1.5' region.  The identifications below are from Paul Hodge's 1978 study "The structure and content of IC 1613" and Borissova et al.  2004 paper "The catalogue of OB associations in IC 1613".


[H78] 10 = [BKG04] G7, the brightest patch, is on the west edge and seen as moderately bright, small, 12" diameter.  A star or stellar object is involved.  Close northeast and southeast are [H78] 13 = [BKG2004] G11 and [H78] 14 = [BKG2004] G14, both easily seen as fairly faint glows, ~15" diameter.  [H78] 17 = [BKG2004] G25 is very faint knot 1' E of [H78] 13 and [H78] 15 = [BKG2004] G15 was visible 30" S of [H78] 14.  [H78] 11 = [BKG2004] G10 was also easily seen as a 12" knot 1.5' N of [H78] 10.


18" (9/15/07): faint, very large, irregular glow, roughly elongated 4:3 SW-NE, ~8'x6'.  A mag 10.5 star is just at the west edge of the glow. A very small knot (HII region?) or core is faintly visible just 2' E or ENE of the mag 10.5 star.  There appears to be a very faint detached piece to the NE about 7' from the mag 10.5 star.  Located ~12' S of  mag 7.2 HD 6375.


13.1" (12/22/84): faint, large, extremely diffuse.  This Local Group member appears as an irregular hazy region with a large brighter section to the NE and a fainter section to the SW.  No visible core.  Several brighter stars are in the field includes a star at the SW edge.  Located 46' N of 26 Ceti.


Max Wolf discovered IC 1613 on a plates taken with the Bruce 16-inch telescope in Sep 1906.  Wolf's position (given in 1885 coordinates) is ~10' south and 1.5 minutes of time preceding the galaxy.  As he used BD stars to measure positions, its very possible the coordinates for the "densest part" are for 1855.  If so, his position is near the center of IC 1613!


William Baade first showed it was extragalactic in 1935 and a year later Hubble included it as a Local Group member.  The distance is ~2.4 million light years.