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14376Re: Dark Line, Spikey Star Problems

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  • havane45
    Apr 1, 2007
      --- In William-Optics@yahoogroups.com, "Timm Bottoni" <t.bottoni@...>
      wrote:
      >
      >
      > Hi,
      >
      > I think it's a much more common thing than people realized. And since
      > it doesn't effect visual use, and many people don't find it all that
      > objectionable, and it seems like it is easy to negate with a slight
      > aperture mask, I pretty much consider it to be almost a non-issue for
      > most people. I wonder how many scopes besides the ones that have been
      > mentioned here also show this effect or similar effects?
      >
      > I was looking at a book in Costco on Astronomy and notices all sorts of
      > pictures, professionally shot, published in a book, that had all sorts
      > of spikes and dark lanes in various shots.
      >
      > I just spotted a picture posted on a CN post taken with a SV NHNG that
      > also shows the same thing, and I recall that many scopes show these
      > effects, so it's clearly a common design comprimise that many
      > manufacturers and customers have lived with for years.
      >
      >
      http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/1504389\
      > /page/1/view/collapsed/sb/5/o/all/fpart/all/vc/1
      >
      <http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/150438\
      > 9/page/1/view/collapsed/sb/5/o/all/fpart/all/vc/1>
      >
      > On my original 80SD lens, I could see the spacers, but on my 80FD lens I
      > can't so it seems likely that the various manufacturers have gone with
      > maximum aperture.
      >
      > I honstly don't think it's a big deal - I would love a FLT132 some day
      > when I can afford one, and a mount to go with it, and the time to use
      > it, and some clear and dark skies - oh well, you get the idea.
      >
      > Timm
      >


      Hi Timm,

      This is obvious on the picture.

      So, we know for now that it happened on TMB, Tak and SV too.
      I bet it also happened on XX expensive refractors but the difference
      is that they do not say anything about it ; it must be harder to
      accept ...
      It must be a matter of design and as you said not really objectionable.
      May be this will be the end of what was sometimes looking, IMO, as WO
      bashing.

      Laurent
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