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Thread: Object of the Week July 22, 2012 – Campbell’s Hydrogen Star

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    Object of the Week July 22, 2012 – Campbell’s Hydrogen Star

    Campbell’s Hydrogen Star (PK 64+5.1, PN G 64.7+05.0, Hen 2-438, BD +30 3639)

    „Red“ Planetary Nebula

    Cygnus

    Size: 6“
    Mag: 11,3 (CS)

    RA 19 34 45
    DEC +30 30 59

    Cambell’s Hydrogen Star is a very unusual WR star, which has very strong hydrogen lines and missing green oxygen lines.

    The star itself was cataloged through the visual Bonner Durchmusterung (that’s why BN) as the usual star BD +30 3638. Williamina Fleming discovered the unusual spectrum of this star 1890. Three years later William Campbell reported again about the bright H-alpha emission lines. He also detected a nebulous character with his Spectrometer.


    The visual interesting detail is the 5” nebula around the central star and the color.

    The halo itself can be seen with telescopes from the 12”-14” range. Under good to very good seeing the halo could be resolved as a very small ring with better defined and brighter SE and NW ring parts. Hß filters help to resolve the halo from bright and disturbing CS (10,3mag). UHC and [OIII] doesn’t help.
    Also very interesting and exciting is the color of the PN. It is one of the few Deep-Sky-Objects from what we can observe visually its red characteristic. Most people with mid range telescopes reported a red or orange CS. But the color itself is formed from the halo. My own experience with 27” showed a white CS and a red to orange halo/ring. There are other reports and observations which confirm this.

    What do you see?

    "GIVE IT A GO AND LET US KNOW"

    GOOD LUCK AND GREAT VIEWING!

    sketch, 16", 697x, Seeing II, fst 6m5+ (home)
    BD303639.jpg

    Subaru Telescope, National Astronomical Observatory of Japan (NAOJ)
    foto987.jpg
    Clear Skies, uwe
    http://www.deepsky-visuell.de
    Germany

    27" f/4,2

  2. #2
    Member Howard B's Avatar
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    Hi Uwe,

    This was a popular object at the Golden State Star Party last week! I had a look with my 28 inch f/4 and saw Campbell's Hydrogen Star pretty much as shown in the photo you attached during the moments when the seeing settled down using 408x. I tried all my filters but the non-filtered view was by far the most satisfying, and if anything the red color of the ring was a little more saturated than in the photo. I haven't scanned my notes and sketch yet but will hopefully remember to post them here when I do. This is a great object!
    Howard
    28 inch f/4 alt-az Newtonian

  3. #3
    Member hajuem's Avatar
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    Hello(Servus) Uwe

    Howdy again this forum!
    BD +30 3639 - "Campbell's Hydrogen Star" is on my to do list! Your drawing is my motivation

    Lg of Ha-ju

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    Hi Howard and Hajü,

    thanks for the reply.

    When I understand you right Howard, the reddish color was only situated in the ring and not the star itself? That is exactly my experience with that object and with similar aperture.

    Hajü, the sketch is difficult to interpret. The central star is much brighter and the nebula much fainter than in the sketch. But you know the problem of the gray-scale.
    Clear Skies, uwe
    http://www.deepsky-visuell.de
    Germany

    27" f/4,2

  5. #5
    Member Howard B's Avatar
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    That's right Uwe, the ring was red and the star was white with dark space between them very much like the photo from the Subaru Telescope.
    Howard
    28 inch f/4 alt-az Newtonian

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