Hemisphere:  Northern  ·  Constellation: Andromeda (And)

Image of the day 09/02/2016

    ARP273 - The Rose, 


            Jason Guenzel
    ARP273 - The Rose
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    Technical card

    Imaging telescopes or lenses: CELESTRON EdgeHD 800

    Imaging cameras: ZWO ASI1600MM-Cool

    Mounts: Orion Atlas Pro AZ/EQ-G

    Guiding telescopes or lenses: CELESTRON EdgeHD 800

    Guiding cameras: ASI120MM

    Focal reducers: Celestron 0.7x Focal Reducer

    Software: Sequence Generator Pro  ·  PixInsight  ·  Adobe Photoshop  ·  PHD 2

    Accessory: Moonlite CHL 2.5" Large Format Crayford Edge Focuser  ·  Orion Thin Off-Axis Guider (TOAG)

    Dates:Aug. 8, 2016Aug. 9, 2016Aug. 11, 2016Aug. 26, 2016

    Blue: 25x180" -20C bin 1x1
    Green: 25x180" -20C bin 1x1
    Luminance: 121x180" (gain: 0.00) -20C bin 1x1
    Red: 25x180" (gain: -20.00) bin 1x1

    Integration: 9.8 hours

    Darks: ~50

    Flats: ~50

    Bias: ~256

    Avg. Moon age: 10.82 days

    Avg. Moon phase: 39.90%

    Bortle Dark-Sky Scale: 5.00

    Basic astrometry details

    Astrometry.net job: 1214700

    RA center: 2h 21' 30"

    DEC center: +39° 22' 30"

    Pixel scale: 0.526 arcsec/pixel

    Orientation: -92.815 degrees

    Field radius: 0.186 degrees

    Resolution: 2015x1552

    Data source: Backyard


    ARP273 consists of the interacting pair of UGC1810 (larger) and UGC1813 (smaller). This pair lies 300mly distant in Andromeda. The pairing gets the “Rose” nickname from the obvious appearance of a rose blossom and stem. Research suggests the smaller, UGC1813 actually passed through UGC1810 at some time in the not so distant past.

    UGC1810 (larger galaxy)
    The gravitational tidal forces unraveled the outer arm and created numerous clumps of star-forming material that takes on the blue tint of massive young stars. Visible at the bottom (in this view) of this arm is a suspected third galaxy which, in the Hubble image, shows a distinct nucleus and perhaps some spiral arms. It is difficult to make out in this image, or Hubble’s for that matter.

    UGC1813 (smaller galaxy)
    This one appears to be a barred spiral that lost its arms in the merger. The central bar is also home to massive star forming regions which lends more evidence to the recent collision theory. That, and the fact that there is a tidal tail connecting the two spanning tens of thousands of light years. The tail extends on the opposite side of UGC1813 also. This is likely the remnant of a once-coherent spiral structure.

    This ranks up as one of my favorite galaxy pairs, though it only measures 1.7 x 0.6 arcminutes! Continuing along in my quest for tiny objects, this was another one where I tried 2x drizzle stacking to increase my resolution. I fully processed it and then in the end, I scaled it back to capture resolution and cropped it in significantly for presentation.

    I’m pretty happy with the result but there are some serious challenges here that were hard to deal with.

    Rev A - Original Process
    Rev B - Pulls back some of the halos of the large stars



      ARP273 - The Rose, 


            Jason Guenzel
    • Final
      ARP273 - The Rose, 


            Jason Guenzel

    Sky plot

    Sky plot


    ARP273 - The Rose, 


            Jason Guenzel