Author Topic: Frosti  (Read 512 times)

mccarthymark

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Frosti
« on: February 04, 2017, 10:04:34 AM »
Last week I observed at the Chaparral Trailhead parking lot at Pinnacles.  Many curious people asked about my scope as they came back from their hikes.  The lot emptied out after dark, after which a chorus of coyotes started up.  They seemed to be among the High Peaks and were purposely echoing their calls off the rock cliffs.  First one group, then another, until the sky was loud with their calls.

Transparency was poor and dew formed quickly; the shroud on my 20-inch scope was well-soaked.  Around 11pm I noticed it was crinkly -- it had frozen.  There were ice crystals forming on every exposed surface.  I had to scrape ice off the plexiglass window of my chart holder.  I myself was not cold, wearing a down jacket and snow boots.  It was 25°.  It made me think of Bjork's song "Frosti," which I replayed in my head through the night (https://www.youtube.com/watch?v=-i1SqFJ3K8Q)

NGC 2521: Gx in Lynx: Three galaxies in view.  Brightest is NGC 2521, fairly bright, small, bright core, elongated 2:1 NE-SW.  The other two are UGC 2421 and MCG+10-12-070.  The UGC is small, pretty faint, brighter core with AV, elongated NW-SW 3:1.  The MCG is very faint, small, and round.  These three plus a star, Z Lyn, in the northern corner, form a nearly perfect square.

NGC 2488: Gx in Lynx: Bright core, stellar nucleus, 3:1 edge on NW-SE; overall faint and small.  I see two other galaxies in the field, one to N and another to SW.  Both small round and very faint, though the one to the north (UGC 4164) has a stellar nucleus.  [The one to the SW is a close galaxy pair MCG+09-13-112 & -111, both of which are 17B and ~0.5" square, but perhaps became visible to me with their combined glow.]

NGC 2469: Gx in Lynx.  Four galaxies in a string.  NGC 2469 is brightest and comparatively large (though itself small), elongated 3:2 nearly N-S.  The others -- NGC 2463, NGC 2462, & NGC 2458 --are small, faint and round.  Near a bright star which hinders the view somewhat.  The galaxies have a range of redshift from 0.01 to 0.047, so this is a chance alignment than a cluster If I had panned my scope a little beyond NGC 2469 I could have seen a fifth in this string, NGC 2472, an extremely faint and small item.

NGC 2347 + IC 2179:  Nice.  Both galaxies near stars and look like a double-double but with galaxies as the B components.  NGC is a little brighter and larger, with a bright core enhanced with AV, 3-1 N-S.  The IC has a stellar nucleus and is small, round, fairly faint.

NGC 2517: Gx in Puppis: Bright core, stellar nucleus, small, 3:1 ENE-WSW with tapering tips.  Some mottling in the halo and core.  Very dense field; I'm sure this is highly obscured by the Milky Way.  Did not see nearby PGC.

NGC 2525: Pretty large, diffuse, low surface brightness.  Irregularly oval shape with mottling; in a dense field of stars.  It is an SBc.

IC 2375 / 77 / 79: Three galaxies piled up, in different orientations.  Seen direct vision, brightens with averted -- call them all fairly faint, all of them small.  IC 2375 was noticeably elongated 4:1 E-W. IC 2377, in the middle, was oval, NE-SW.  IC 2379 was also oval but pointed NW-SE, and had a brighter core.

NGC 2881-1 / -2 = Arp 275: Pretty faint, fairly large, irregular tear-drop shape with a wing coming off it to the west -- a double system.  Mottled halo with several superimposed stars.  IC 2782 is to the south, fairly faint, small, with a stellar nucleus and a round diffuse halo.

MCG-2-25-6 = Arp 221: Two faint stellar nuclei with a lopsided, diffuse halo brighter to the east.  Faint -- can see with direct vision but averted brightens.  Used 333x to better resolve the second nucleus.  There is an extremely faint, very small condensation on the west rim of the halo.  Arp classes this under "amorphous spiral arms."

NGC 2993, 2992 = Arp 245: Two galaxies seem to have a connecting bridge.  NGC 2992 is small, elongated NNE-SSW and moderately bright, the brighter of the pair.  NGC 2993 is smaller and round [did not see the streamer whisking from it to the east.  Arp says of these: "Appearance of fission"].

NGC 2775, Gx in Cancer: Looks like a more distant version of M31; it is 62mly away.  Bright & large, it has a bright compact round nucleus with brighter elongated core and diffuse, slowly fading halo, 3:2 NW-SE.  I see subtle hints of spiral structure.  The galaxy sits above the bowl of a mini big dipper asterism.  It is a Sa spiral and forms a trio with two other galaxies: NGC 2773 to the NW and NGC 2777 to the NE.  NGC 2773 is a small, fairly faint rice grain of even brightness 3:1 orientated E-W on the edge of the FOV.  NGC 2777 is small, faint, and nearly round but with a small stellar nucleus.

NGC 2936 & 2937 = Arp 142: Small, faint bean shaped glow with two brighter condensations; used 333x to clearly separate the two galaxies.  NGC 2936 is the northern component and is larger, with the brightest part near the NE edge and a faint smudge of a halo trailing to the SW, like a smeared fingerprint.  NGC 2937 is the second component and is small, faint, and round and is tucked underneath the other, like an eye under an eyebrow.

NGC 2291 / 2294 / 2290 / 2288 / 2289: I was attracted to this group as it lies in region near the Gemini-Auriga boarder relatively devoid of DSOs.  Five galaxies in a wedge shape, all more or less the same faintness and smallness, differing in the brightness of the cores and diffuseness of their halos.  Four were in a nice little arc, starting with NGC 2991, small, faint and round.  Next, heading south, NGC 2289 was the brightest, with a round core and very faint halo E-W.  Very close to it was the very small and very faint round glow of NGC 2288.  Last in the string and bright was N2290, with a small brighter core and a very faint diffuse halo 3:1 NE-SW.  NGC 2294 was to the NE, very small and faint patch.  Interstellarum plots IC 2173 as a sixth galaxy in this area, which I could not find (other than suspecting a couple faint round things which were likely threshold magnitude stars).  I found later that NGC 2288 is the same as IC 2173

NGC 2874 / 2782 = Arp 307: The western component, NGC 2872, has a small bright core, with a regular, if diffuse, halo, 3:1 NNW-SSE.  The eastern component, NGC 2874, is larger but fainter, with a stellar nucleus sitting lopsided to the north end of a clearly disrupted halo, which has a bright rim to the south and a very faint arc sprouting from the southern tip and headed toward NGC 2782.  I failed to notice three other NGCs in this field: NGC 2785 a small bright dot at the northern tip of NGC 2874's halo; NGC 2871 a similar point at the NW tip of NGC 2872's halo; and NGC 2873, a small and faint galaxy to the north of the main pair.

NGC 2911: Fairly bright, even surface brightness cloud with a small bright core and quasi-stellar nucleus.  3:1 NW-SE.  There’s something strange about the halo, maybe some spiral or mottling, mirrored on each side of the halo along the major axis.

NGC 3016 / 3024 / 3020: Nice! a trio.  Faint -- can see with direct vision, but averted adds to brightness.  NGC 3020 is to the north, has a bright elongated core and the largest halo of the three, diffuse and elongated 4:1 E-W.  NGC 3024 is to the east and is nearly an edge on, with a quasi-stellar nucleus.  NGC 3016 is to the far SW and is the smallest but with a sharply brighter core.  I did not see NGC 3019 which sits in the middle of the triangle.

UGC 4881 = Arp 55: At 333x, very small, very faint irregular glow, slightly elongated E-W, with a slight brightening in western edge of the glow.
Mark

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Re: Frosti
« Reply #1 on: February 05, 2017, 12:01:24 AM »
Glad you had fun and held down the Pinnacles, McCarthy. Your buddies were saying good things about you behind your back at Dinosaur Point. Delighted to report we had no freezing dew. Big boy work you did with all those relatively faint galaxy groups.

Here's to the coyotes!
TAC - astro anarchy at work <*>

sgottlieb

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Re: Frosti
« Reply #2 on: February 05, 2017, 11:16:25 AM »
Wow, a real Arp-fest!  Even NGC 2911, near the end of your report, is Arp 232.  Great report.

As Mark knows, I have an article coming up in a few months in Sky & Tel on Arp interacting galaxies and UGC 4881 = Arp 55 = The Grasshopper (last in the report) is one of the featured galaxies.