Results 1 to 9 of 9

Thread: Object of the Week February 21,2016 NGC3081 The King of The Resonances Rings

  1. #1
    Co-Founder DSF.com Jimi Lowrey's Avatar
    Join Date
    Feb 2012
    Location
    Fort Davis Texas
    Posts
    570

    Object of the Week February 21,2016 NGC3081 The King of The Resonances Rings

    NGC 3081

    Hydra

    Ra
    09 59 29
    Dec
    -22 49 34

    Type
    Seyfert 2

    Mag
    12.8

    --------------------------------------------
    The last few years I have been observing SB type rings and so far this is the best of the resonances rings that I have found.

    NGC-3081 Hubble.jpg

    NGC 3081 was found by William Herschel on Dec 21, 1786. I wounder if he thought he had found another PN? According to professor Ron Buta's paper on NGC 3081 the are four rings in this unusual galaxy " NGC 3081 is a early-type barred spiral having four well-defined resonance rings: a nuclear ring, an inner ring, an outer R1 ring, and an outer R2."

    NGC 3081 ring structure.gif

    He also says that there has been little to no interaction with other galaxies and this is why the rings are in a pristine shape. DR Buta,s Paper http://iopscience.iop.org/article/10...3365.text.html

    NGC 3081 B&W.jpg

    From my observations of NGC 3081 RI and R2 rings are very faint and not seen visually and only shows up in deep images of the galaxy. The view of the inner rings are stunning and hard to put into words. Steve G, Howard B and I had a good view or the inner rings one night and Howard did a awesome drawing of it I hope he will post it here for us to see.

    I hope you get a chance to view the King of the SB rings soon and will,

    "Give it a go and let us know! "
    Clear Skies,

    Jimi Lowrey
    Fort Davis Texas

    48"F4 OMI/TEC
    28'F4 ATM

  2. #2
    Member Howard B's Avatar
    Join Date
    Feb 2012
    Location
    Scappoose, Oregon USA
    Posts
    571
    That was quite of view of 3081 through your scope Jimi, and here's my notes and sketch:

    "Excellent ring galaxy! Bright, concentrated core with a tiny stellar (nucleus). The ring is brightest on each end and they both have a subtle texture. 488x."

    N3081_crop.jpg N3081_cropinvert.jpg

    I have yet to look at 3081 with my own scopes, so this is my only observation of it so far - and it will certainly be hard to top!
    Howard
    30-inch f/2.7 alt-az Newtonian
    https://sites.google.com/site/howardbanichhomepage/
    https://sites.google.com/site/sprays...pemirrors/home
    Contributing Editor, Sky & Telescope magazine

  3. #3
    Member
    Join Date
    Feb 2012
    Location
    Germany
    Posts
    813
    I just visited the galaxy at June 2015. Location was Gamsberg in Namibia, perhaps one of the best observing places in the world. Funny thing, I used the smallest telescope that was available for visual observation - a 17.5" Dobson.

    17,5"; 289x; NELM 7m+, Seeing III
    NGC3081.jpg
    Clear Skies, uwe
    http://www.deepsky-visuell.de
    Germany

    27" f/4,2

  4. #4
    Member
    Join Date
    Jun 2014
    Location
    La Serena, Chile
    Posts
    427
    I haven't observed this galaxy myself yet. However, I find it fascinating that the pictures show that the major axis of the nucleus doesn't align with the major axis of the ring, while both Howard and Uwe have drawn the major axes aligned. I wonder what it will look like through my telescope!

  5. #5
    Member Steve Gottlieb's Avatar
    Join Date
    Feb 2012
    Location
    Northern California
    Posts
    804
    These are my eyepiece notes (observing with Howard and Jimi) of NGC 3081.

    48" (4/18/15): This beautiful ring galaxy was viewed at 488x and 610x. It is very sharply concentrated with a very bright, roundish core (slightly oval at 610x) that gradually increases to a stellar nucleus. The surface brightness drops significantly in the inner halo, but then brightens at the edge to a well defined oval ring, extending 5:3 WSW-ENE, ~1.3'x0.8'. The ring is fairly narrow and brighten slightly at the ends of the major axis (southwest and northeast ends). This is a very distinctive object!
    Steve
    24" f/3.7 Starstructure
    18" f/4.3 Starmaster
    Adventures in Deep Space
    Contributing Editor, Sky & Tel

  6. #6
    Member Howard B's Avatar
    Join Date
    Feb 2012
    Location
    Scappoose, Oregon USA
    Posts
    571
    Good catch - the major axis of the nucleus doesn't match that of the outer ring in the photos, but through the eyepiece it was a different story. I've found this to be true with some planetary nebula that have oddly shaped inner halos but they look perfectly round visually.
    Howard
    30-inch f/2.7 alt-az Newtonian
    https://sites.google.com/site/howardbanichhomepage/
    https://sites.google.com/site/sprays...pemirrors/home
    Contributing Editor, Sky & Telescope magazine

  7. #7
    Member
    Join Date
    Jun 2014
    Location
    La Serena, Chile
    Posts
    427
    Yes, I am well aware of objects appearing differently visually then they do on photo's. I suppose that's due to several causes among which photo's having been processed to bring out faint details more brightly than they are and our brains interpreting what we see while having a tendency to recognise patterns everywhere. Steve discribes the core to increase inbrightness inwards which very likely adds to the effect. That all is why I am looking forward to seeing this object with my own eyes!

  8. #8
    Member deepskytraveler's Avatar
    Join Date
    Feb 2012
    Location
    Wheaton, IL USA
    Posts
    106
    Wow, what a fascinating galaxy Jimi, thanks for sharing. Can't wait to give it a try; although with only 15" of aperture, typical Ohio skies, and a transit altitude of only 30° I don't have high expectations.

    Looking at the Hubble image there seems to be several galaxies in the foreground of NGC 3081. In particular around the 7-8 o'clock position there seems to a rather large loose-spiral galaxy and several much smaller galaxies, including one that is shaped like an eye. With a quick perusal of MegaStar and SkyTools I didn't see other galaxies noted. Are these foreground galaxies or are they part of 3081's structure?
    Clear Skies,

    Mark Friedman
    Wheaton, IL USA

  9. #9
    Member Steve Gottlieb's Avatar
    Join Date
    Feb 2012
    Location
    Northern California
    Posts
    804
    The two galaxies at 7-8 PM are visible on the DSS, but appear stellar. The colorized WikiSky image shows them very well (zoom in on NGC 3081). Neither object is in NED or HyperLeda, so they don't appear to have galaxy designations, though the one on the east (left) side is in the 2MASS point-source catalogue as 09593161-2249525. NOMAD lists a B magnitude of 19.9 - don't know if that's reliable. The galaxy on the west (right) side looks like another ring of some type.
    Last edited by Steve Gottlieb; February 24th, 2016 at 09:14 PM.
    Steve
    24" f/3.7 Starstructure
    18" f/4.3 Starmaster
    Adventures in Deep Space
    Contributing Editor, Sky & Tel

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •