Hemisphere:  Northern  ·  Contains:  PK149-09.1

Image of the day 12/23/2019

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    Hartl-Dengel-Weinberger 3 (HDW 3), 


            Peter Goodhew
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    Hartl-Dengel-Weinberger 3 (HDW 3)

    Imaging telescopes or lenses: APM Telescopes TMB - LZOS Apo refractor 152/1200

    Imaging cameras: QSI 6120wsg-8

    Mounts: 10Micron GM2000HPS II

    Guiding cameras: Starlight Xpress Lodestar Autoguider X2

    Filters: Astrodon Lum  ·  Astrodon Blue  ·  Green  ·  Red  ·  Astrodon SII 5nm  ·  Astrodon OIII 3 nm  ·  Astrodon 5nm H-Alpha filter

    Astrodon 5nm H-Alpha filter: 76x1800" bin 2x2
    Astrodon Blue: 17x300" bin 1x1
    Green: 20x300" bin 1x1
    Astrodon Lum: 39x300" bin 1x1
    Astrodon OIII 3 nm: 51x1800" bin 2x2
    Red: 20x300" bin 1x1

    Integration: 71.5 hours

    Astrometry.net job: 3128049

    RA center: 3h 27' 16"

    DEC center: +45° 25' 1"

    Pixel scale: 0.534 arcsec/pixel

    Orientation: -3.716 degrees

    Field radius: 0.359 degrees

    Resolution: 4100x2577

    Locations: e-Eye, Fregenal de la Sierra, Extramadura, Spain

    Data source: Own remote observatory

    Remote source: e-EyE Extremadura


    Hartl-Dengel-Weinberger 3 (HDW 3, PK149-09.1, PNG149.4-09.2) is an extremely faint ancient planetary nebula in the constellation Perseus. It is so faint that it is very rarely imaged.
    The progenitor star is the small blue star at the 5 o-clock position just below the large yellow star in HDW 3. The progenitor is not, as one would expect, in the centre of the nebula. This is because it is moving rapidly in a north-westerly direction. It is moving through a dense area of interstellar medium (ISM). This ISM is slowing down HDW 3, creating a shock front and the unusual "braided" appearance. As the star isn't slowed by the ISM it has continued to move and is thus no longer at the centre of HDW 3 and is slowly overtaking HDW 3. This causes the shock front to be brighter as it's getting more ultraviolet radiation, whereas of opposite side of HDW 3 is getting less UV radiation and has become invisible. This movement of the star causes differential excitation of the shell. OIII emission, which requires higher energy of the ionizing radiation than HII emission, only happens close to the star.



    Peter Goodhew
    License: None (All rights reserved)


      Hartl-Dengel-Weinberger 3 (HDW 3), 


            Peter Goodhew
      Hartl-Dengel-Weinberger 3 (HDW 3), 


            Peter Goodhew
    • Final
      Hartl-Dengel-Weinberger 3 (HDW 3), 


            Peter Goodhew


    Description: crop


    Description: small stars sharpened

    Sky plot

    Sky plot


    Hartl-Dengel-Weinberger 3 (HDW 3), 


            Peter Goodhew