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Ivan Maly
July 6th, 2014, 12:20 PM
Has anyone here seen anything of the spiral arms in IC 342? What does it take aperture-, magnification-, and conditions-wise, and what exactly can be seen? I have so far been unsuccessful with my 12" SCT, trying from 55 to 375x. The field is rich and in fact there is a condensation of Milky Way stars, which looks like the galaxy in binoculars. With the telescope, however, only the core is seen, not a trace of even the (photographically) brightest fragments of the spiral arms.

Jim Chandler
July 6th, 2014, 02:59 PM
My most recent log note for IC 342 from Feb. 2011:

30" f/4.5, Mason County, Texas, ~1500', Trans. 8/10, Seeing 4/10, 94x - 226x

Large, low surface brightness, face-on spriral. Bright core, surrounded by obvious nebulosity, but the arms are difficult to resolve. One arm, on the NW side, was held with averted. A second, opposite the first, was tantalizing in glimpses, but never really held.

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Over the years, the galaxy has been detectable in aperture as small as 4" ( TV 101, 32x, "Faintly nebulous, at the limit of detection."), but I've only seen spiral arm detail in the 25" or larger aperture.

star drop
July 6th, 2014, 04:38 PM
The arms are not that obvious in my 25" telescope.

Ivan Maly
July 6th, 2014, 07:37 PM
Thank you for your responses, gentlemen.

Uwe Glahn
July 6th, 2014, 08:41 PM
During a quick and dirty observation with 27" and 172x (AP 4mm) under very good transparency (NELM over 7mag) I roughly sketched three arms. The northern one was the longest and most prominent arm. I also noted "very faint, only partly visible". With 14,5" and 16" the galaxy was visible but without the spirals.