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Thread: Object of the Week, 24 January 2016 - VV 169 = Arp 327 = HCG 34

  1. #1
    Member Steve Gottlieb's Avatar
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    Object of the Week, 24 January 2016 - VV 169 = Arp 327 = HCG 34

    Object of the Week, 24 January 2016

    VV 169 = Arp 327 = HCG 34
    RA: 05h 21m 47.4s
    Dec: +06° 40' 37"
    Type: Galaxy Chain (quartet)
    Size: 1.25' length
    Light travel time: ~425 million years

    Boris Voronstov-Velyaminov first catalogued this group in his 1959 Atlas and Catalogue of Interacting Galaxies. He labeled four galaxies in a chain (a, b, c, d) with NGC 1875 = VV 169a.

    VV 169.jpg

    Halton Arp followed suit and included Arp 327 in the category of "Chains of Galaxies" in his 1966 Atlas of Peculiar Galaxies

    Arp 327.jpg

    Finally, Paul Hickson included it in his 1982 paper Systematic Properties of Compact Groups of Galaxies. HCG 34 is the only group in Orion!

    HCG 16.jpg

    The elliptical galaxy NGC 1875 (RC3 classifies it as a possible lenticular) is the dominant member. It was missed by the Herschels and discovered by Albert Marth using William Lassell's 48" f/9.4 fork-mounted speculum-reflector in 1863. I'm guessing a 10" is close to the minimum aperture to reveal this galaxy -- perhaps forum members can test this theory! Here are 3 of my own observations, the last of course on Jimi's scope --

    NGC 1875 = HCG 34A = VV 169a
    17.5"(220x): faint, round, 20" diameter, very faint stellar nucleus. Located 1.0' E of a mag 13.5 star.

    24" (375x): moderately bright, fairly small, round, 0.4' diameter, well concentrated with a small brighter core. A mag 13 star lies 1' W and a mag 16 star is just 0.4' W of center.

    48" (488x): bright, round, 30" diameter, brighter core.


    Three much fainter galaxies extend in a short string to the southeast (in order from NGC 1875: HCG 34D/34C/34B). Hickson measured total B magnitudes of 18.4, 17.3 and 17.6, respectively, for the trio. I was able to glimpse HCG 34B and 34C in my 24" though they were just dim blurs, and I missed the virtually stellar HCG 34D.

    HCG 34B = VV 169c
    24" (375x): extremely faint, very small, slightly elongated, ~10" diameter.

    48" (488x): faint, very small, elongated 2:1 ~N-S, 20"x10".

    HCG 34C = VV 169b
    24" (375x): extremely faint and small, round, ~6" diameter.

    48" (488x): faint, very small, slightly elongated E-W, 12"x8".

    HCG 34D = VV 169d
    48" (488x): extremely faint and small, round, 6" diameter.

    Anotated.jpg


    Although Hickson only included 4 members in HCG 34, you'll notice LEDA 1306245 (Megastar labels it MAC 0521+0643B) labeled in the image just above (3.5' NE of NGC 1875). It shares a similar redshift with the quartet, so it really should have been included as a 5th member. In fact, if you miss B, C and D, go after for this galaxy -- I found it slightly easier!

    This is a challenging OOTW that should be attempted on a transparent night, but whether you're successful or not with the fainter members,
    GIVE IT A GO AND LET US KNOW!
    Last edited by Steve Gottlieb; January 25th, 2016 at 03:50 PM.
    Steve
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  2. #2
    Member akarsh's Avatar
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    Steve, the topic still says HCG 16... maybe because it can't be changed? If I recall right, I think HCG 16 has a bunch of bright galaxies.
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  3. #3
    Member Steve Gottlieb's Avatar
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    Thanks for catching this typo, Akarsh. I fixed the error on the title of my post and Dragan just corrected the title of the thread.
    Last edited by Steve Gottlieb; January 25th, 2016 at 04:20 PM.
    Steve
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    Challenging but morphological interesting group. Here are my results.

    27", 586x, NELM 6m5+
    difficult HCG group; dominated by a as a round, direct vision object with concentration to its middle; b and c difficult to hold with averted vision, double system which can be separated; d is popping in and out of view as a stellar plob, can not hold it with averted vision
    HCG34.jpg
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  5. #5
    Member Howard B's Avatar
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    My latest observation of Hickson 34 is from 2005 under mag 6.0 skies:

    "Well, I can see galaxies B and C but D is still out of reach. The seeing is quite soft so perhaps it would be within reach in steadier seeing. Even so, it took extreme averted vision to see C, so who knows... 569x, 28 inch f4."

    Hickson34_crop.jpg Hickson34_cropinvert.jpg

    I have a 2002 observation with my old 20 inch - on an even worse night - and could only see NGC 1875.
    Howard
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    I observed this galaxy last night in my 16 inch Dob here in my suburban mag 5 location. The galaxy was very faint and tough to pick out even with averted vision but I was pleased to spot it.

    No chance on those other fainter galaxies.

    I noted that only 15 of the other 1400 galaxies I have observed were more distant so this must be a very inherantly bright object.

    Mark
    Based in Bristol in the UK

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