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Hemisphere:  Northern

Image of the day 01/09/2020

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    EGB 4 (Ellis-Grayson-Bond 4), 


            Peter Goodhew
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    EGB 4 (Ellis-Grayson-Bond 4)

    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: 56x1800" bin 2x2
    Astrodon Blue: 15x300" bin 1x1
    Green: 15x300" bin 1x1
    Astrodon Lum: 20x600" bin 1x1
    Astrodon OIII 3 nm: 25x1800" bin 2x2
    Red: 15x300" bin 1x1

    Integration: 47.6 hours job: 3152620

    RA center: 6h 29' 34"

    DEC center: +71° 4' 36"

    Pixel scale: 0.533 arcsec/pixel

    Orientation: -6.731 degrees

    Field radius: 0.368 degrees

    Resolution: 4150x2734

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

    Data source: Own remote observatory

    Remote source: e-EyE Extremadura


    EGB 4 (a nebula discovered by Ellis, Grayson, & Bond in 1984) is NOT a comet, despite it's comet-like appearance. It is an emission nebula surrounding a catacylismic binary star system called BZ Cam in the constellation of Camelopardis.

    It has an unusual bow-shock structure as BZ Cam (with it's associated wind) moves through the interstellar medium, similar to the bow wave in front of a ship that is moving through water.

    BZ Cam is believed to be a white dwarf star that is accreting mass from an accompanying main-sequence star of 0.3-0.4 solar masses.
    It is around 2,500 light years away, and has a space velocity of 125 km/second.

    I can only find one previous image of EGB 4 online, a NASA APOD from 2000, so I believe this could be the first amateur image and the first colour image.

    Yes it's ridiculously faint!


    THE ASTRONOMICAL JOURNAL, 115:286-295, 1998 January © 1998. The American Astronomical Society.



    Peter Goodhew
    License: None (All rights reserved)


      EGB 4 (Ellis-Grayson-Bond 4), 


            Peter Goodhew
      EGB 4 (Ellis-Grayson-Bond 4), 


            Peter Goodhew
    • Final
      EGB 4 (Ellis-Grayson-Bond 4), 


            Peter Goodhew


    Description: star colour

    Sky plot

    Sky plot


    EGB 4 (Ellis-Grayson-Bond 4), 


            Peter Goodhew