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Re: Double star observing

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  • kentblackwell
    Hello, Dave. I certainly agree about the UHC filter causing ghost images. There is NO way Antares could be split in my 80mm with a UHC filter in place.
    Message 1 of 11 , Jul 11, 2006
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      Hello, Dave. I certainly agree about the UHC filter causing ghost
      images. There is NO way Antares could be split in my 80mm with a UHC
      filter in place. However, the filter did show a nice green ghost
      image of Antares! I'm sure that has fooled many observers into
      thinking the UHC magically splits Antares; but not this observer!

      Kent

      --- In delmarvastargazers@yahoogroups.com, David M Groski
      <David.M.Groski@...> wrote:
      >
      > Kent,
      > Antares is one of my favorite challenges. I split is couple of
      times
      > with my 4" f/27 Schief and my 8" f/7. You have to be careful when
      you use
      > a modern day refractor thou. The secondary ghost images that can be
      caused
      > by the atmosphere and the multicoating on the lens will sometimes
      give a
      > faint green ghost. There was thread on one of the astronomy sites a
      few
      > years ago that talked about if you use an UHC filter it made it
      easy to
      > splitt Antares. The problem was that people were just see the green
      ghost
      > image caused by the filter.
      > Speaking of doubles down in Scorpius have you tried the southern
      version
      > of the Double Double. I believe it's Delta Scor. and it located in
      the
      > head of Scorpius.
      >
      > - Dave
      >
      >
      >
      > "kentblackwell" <kent@...>
      > Sent by: delmarvastargazers@yahoogroups.com
      > 07/11/2006 08:22 AM
      > Please respond to
      > delmarvastargazers@yahoogroups.com
      >
      >
      > To
      > delmarvastargazers@yahoogroups.com
      > cc
      >
      > Subject
      > [delmarvastargazers] Double star observing
      >
      >
      >
      >
      >
      >
      > Now that the moon is full one might ask, "What in the heck can I
      > observe?"
      >
      > Last night I managed to split Antares with the little 80mm f/7.5
      TMB.
      > If you want a real challenge give it a try. I had to remove the
      right
      > angle diagonal to eliminate any optical imperfections. Seeing it
      > required a 4mm eyepiece and a 2.5x Barlow, for a whopping 375x!
      That's
      > 120x per inch of aperture. I couldn't split it with my 10" f/5
      > reflector, probably because of the diffraction caused by the spider
      and
      > secondary mirror.
      >
      > At first I didn't see the faint secondary star, but suddenly a
      small
      > greenish dot appeared between Antares and the innermost diffraction
      > ring.
      >
      > So, that's my challenge for the day.
      >
      > Kent Blackwell
      > Virginia Beach, VA
      >
      >
      >
      >
      >
      >
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
      >
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    • kentblackwell
      Oddly, my notes with the 25 reflector indicates the colors as gold primary star and blue-white secondary. My 10 reflector shows the primary as gold and the
      Message 2 of 11 , Jul 11, 2006
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        Oddly, my notes with the 25" reflector indicates the colors as gold
        primary star and blue-white secondary. My 10" reflector shows the
        primary as gold and the secondary green. Both are reflectors. Have
        you noticed smaller scopes often show more pronounced colors?

        Kent Blackwell

        --- In delmarvastargazers@yahoogroups.com, David M Groski
        <David.M.Groski@...> wrote:
        >
        > Thanks Ted, you are correct. in that it's Nu. I didn't do much
        double
        > star observing until I made my Schiefspiegler. Since it has a very
        long
        > focal length it lends itself very well to double observing. Also
        since
        > it's a totally reflective system, there is no false color so the
        colors of
        > the stars are the real thing. Here's another nice one, Alpha Herc.
        The
        > colors are listed as red and green also. It much higher in the sky
        then
        > Antares and the seperation is alittle wider.
        >
        > - Dave
        >
        >
        >
        > "Ted Forte" <twforte@...>
        > Sent by: delmarvastargazers@yahoogroups.com
        > 07/11/2006 03:57 PM
        > Please respond to
        > delmarvastargazers@yahoogroups.com
        >
        >
        > To
        > <delmarvastargazers@yahoogroups.com>
        > cc
        >
        > Subject
        > Re: [delmarvastargazers] Double star observing
        >
        >
        >
        >
        >
        >
        >
        > ----- Original Message -----
        > From: David M Groski
        > To: delmarvastargazers@yahoogroups.com
        > Sent: Tuesday, July 11, 2006 9:10 AM
        > Subject: Re: [delmarvastargazers] Double star observing
        >
        > David Groski wrote
        >
        > >>Speaking of doubles down in Scorpius have you tried the southern
        version
        > of the Double Double. I believe it's Delta Scor. and it located in
        the
        > head of Scorpius. <<
        >
        >
        > The star you are thinking of is Nu Scorpii, I think, also known as
        > Jabbah. Just a bit east of the head of the Scorpion. A fine
        quadruple
        > system.
        >
        > Ted Forte
        >
        >
        >
        > .
        >
        >
        >
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