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Thread: Object of the Week July 3rd, 2016 - NGC6946 The Fireworks Galaxy

  1. #1
    Administrator/Co-Founder Dragan's Avatar
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    Object of the Week July 3rd, 2016 - NGC6946 The Fireworks Galaxy

    NGC6946
    UGC11597
    Arp 29

    Cygnus

    Galaxy

    RA 20 37 52
    DEC 60 09 15

    Mag: 8.8

    Size: 11.6' x 9.8'

    Class: SAB(rs)cd

    What a better way to pay tribute to Americas independence this week than to discuss our own deepsky fireworks! NGC 6946 or the Fireworks Galaxy, is a beautiful face-on spiral located in Cygnus near the border of Cepheus. Discovered on September 9th 1798 by William Herschel, 6946 makes its fame for not only being a wonderfully visual deep sky object in a telescope, but it claims title as being the most active galaxy as far as supernovae observed. Since 1917, we have observed 9 supernovae within NGC6946, with the most recent being in 2008 by UK amateur Ron Arbour.

    Visually, a relatively close neighbor at only 18Mly, NGC6946 makes for a marvelous object. Between its spiral arms, its numerous challenging HII knots brought to our attention by our own Steve Gottlieb in his July 2013 issue of Sky & Telescope to its beautiful counterpart NGC 6939, an Open Cluster just over the border in Cepheus, these objects offer a wonderful sight in all sizes of telescopes. Lower power wide field views offer a stunning "Two-Fer" in the eyepiece, two differing objects visible in the same FOV.

    Lastly, DSF had a short thread in 2013 touching upon those HII regions Steve mentions in his S&T article. You can find that thread here: http://www.deepskyforum.com/showthre...highlight=6946

    For even further information, Universe Today has a great article located here: http://www.universetoday.com/17824/t...dietmar-hager/

    So next time you're out under some dark summer skies, be sure to swing north and find some fireworks in NGC6946. Just how many knots can you see?

    Give it a go and let us know!

    NGC6946-Subaru-GendlerL.jpg
    Clear Dark Skies,
    Dragan Nikin
    25" f/5 Obsession #610 "Toto"
    30" f/4.5 OMI EVO #1 "Tycho"
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  2. #2
    Member kisspeter's Avatar
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    This is a beautiful galaxy and a beautiful couple with the open cluster. I can contribute a drawing from 2012 with my 4" Newtonian. The spiral structure was visible but very difficult.

    4", 40x (1.8° field):
    ngc6939-46_kisspeter.jpg

    And an inverted, rotated and cropped version:
    ngc6939-46_positive_kisspeter.jpg
    Peter Kiss
    deepeye.hu
    Hungary

  3. #3
    Member Ivan Maly's Avatar
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    I reobserved this galaxy a few nights ago with 12" in SQM 21.9 skies and noted the main familiar features. Observing with 16" from the same site three years ago (SQM 21.7 on that night) I recorded that the pair was nicely framed by the 2" Pentax. The cluster was grainy with partial resolution. 225x brought out the "rounded-tipped angle of stars in the cluster, as described by William Herschel". The galaxy sketch from that observation is below (140-225x). "a" and "b" are my own designations; H are Hodge (1969) HII regions, A are Ivanov and Krastev's (2000) OB associations, and HB are HII regions from Bonnarel et al., 1986.


  4. #4
    Member akarsh's Avatar
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    This was one of my favorite galaxies in an 8" telescope, just because of the challenge it presented under poor sky conditions. My friend and I used it for a while as a measure of sky quality.

    This beautiful spiral is so heavily obscured by galactic dust. I find it challenging to see detail in my 18", but here's what I logged under the exceptional skies of Okie-Tex Star Party 2015:

    14mm Pentax eyepiece. Beautiful. Careful observation resolves spiral arms. Knot observed without UHC, but UHC seems to kill it. Galaxy dimly visible with UHC.
    NGC6946.jpg

    I didn't know about Steve's article on the knots. Next time I give it a try, I'll make sure I have Steve's article with me.

    Clear Skies

    Regards
    Akarsh
    18" f/4.5 Obsession dob "Romela"
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  5. #5
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    Nice spiral Dragan.

    My past 5" binocular did not bring out any detail, but shows nice views together with NGC 6946.
    20x125, NELM 6m0+
    NGC6939_NGC6946.jpg

    More intensive views with my former 14.5" shows the faint spiral structure with some HII regions, especially the huge SSC NGC 6946-1447.
    14.5", 202x, NELM 6m5+
    NGC6946.jpg

    Some actual attempts to show details (clusters) within NGC 6946-1447 failed. I once had a quick and dirty look years ago under superb seeing which shows some stellar peaks within the SSC.
    Clear Skies, uwe
    http://www.deepsky-visuell.de
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    27" f/4,2

  6. #6
    Member Howard B's Avatar
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    Better late than never, here's my most recent observation and sketch of 6946:

    "Using the photo from Steve G's S&T article (July 2013 issue) I tracked down all the HII regions... 408x, 21.70 SQM"

    N6946crop.jpg N6946cropinvert.jpg

    I want to make another sketch, hopefully next year, when 6946 is near the meridian because my last few attempts were when the galaxy was well down in the sky. There's a lot to see in 6946 but most of it is rather subtle.
    Howard
    30-inch f/2.7 alt-az Newtonian
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