A few Arp Peculiars (incl Bear Paw) and NGC1023

I finally got in several clear, moonless hours last night, for the first time since Dec 2. The seeing was awful and the transparency was bad, but I would have taken pretty much anything.

I started out with NGC772 / Arp78. I spent about 45 minutes with this one, trying every trick in my bag (direct, averted, scanning, slewing, jiggling, deep breathing, exit pupils from 6mm down to 1mm, etc.) in an effort to detect its principal asymmetric arm. In the end, all I got was a dark lane which defines a fairly sharp, curved edge to the NNE of the core. (This is indeed the edge of the arm, but I couldn't get any of the rest of it.)

Arp78 / NGC772 1/23/2009 19:30UT; Pickering 3, NELM 5, SQM 20.3
16" MCT

Eccentricity immediately apparent, but it takes considerable study to identify orientation. Some knotting in core, giving the appearance of a broken up cometary nucleus. Tried a big exit pupil (55Pl), but more magnification seemed more effective. Dark lane to NNE of core, other edges indistinct. Couldn't really make out the asymmetric arm.

Companion galaxy (NGC770) nearly easier, although in these conditions it takes 375x to confirm that it's not just a fuzzy star.

I had viewed NGC1023 (another of O'Meara's Hidden Treasures) two years ago, but that was before I started sketching. Normally I like a bit of detail in my galaxies, but this one is quite striking in its setting (even if it is virtually detail-free). Anyway, I decided it was worth a sketch.

NGC1023 1/23/2009 19:30UT; Pickering 3, NELM 5, SQM 20.3
16" MCT

Elliptical core with elliptical halo of good extent. Halo about 10° off-axis of linear asterism of 7 stars. The two make a lovely composition.

Two foreground stars visible in halo; one quite bright and the other still direct vision, but barely. [Ed: I didn't notice the companion, but I had forgotten about it so I wasn't looking terribly hard either.]

Next up was the Bear Paw (Arp6). I spent quite a bit of time with this one trying to make out the bear paw shape, but was mostly unsuccessful. I got the knots which define the claws, but no dark lanes between the pads of the paw.

Arp6 1/23/2009 19:30UT; Pickering 3, NELM 5, SQM 20.3
16" MCT

Fairly dim, roughly circular with several small averted vision knots well off center. Fleeting hints of a dark lane or two, but not enough to determine placement or orientation.

Last up was Arp12. The transparency had improved by 1/2 a magnitude at this point, but I still wasn't able to discern which way the arms wound.

Arp6 1/23/2009 19:30UT; Pickering 3, NELM 5.5, SQM 20.4
16" MCT

Mostly just a smudge with a semi-stellar core and nondescript elongation. However, after considerable study it becomes apparent that the elongation flips 90° between averted and direct vision, indicating a bar running NNW-SSE and a halo running ENE-WSW.

Cheers,
-- Jeff.

Very nice Jeff.
The Arp catalogue is one that is worth looking up.

Thanks, Dave.

Yeah, I've been having a lot of fun with the Arps lately. I've found a couple of good observing guides: Kanipe and Webb, which is a bit more slanted toward the science, and Huey, which is a bit more slanted toward observing. I think Michael has one of Alvin Huey's other books (Abell Planetaries or Hickson Galaxy Groups).

Cheers,
-- Jeff.