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  1. #1
    willismat239@earthlink.net's Avatar
    willismat239@earthlink.net Guest

    Default Williams Optics Swan Eyepieces



    I just noticed these on Astronomics' website. Has anyone tried them
    yet? They are listed as having a 72* AFOV. I am considering the 1.25"
    15mm ep, at around $80. I saw that the Burgess 16mm (also listed with
    72* AFOV) is a bit cheaper, but the extra 1mm just might make a (small)
    difference in my short tube refractor, so I'd like to try and get some
    feedack on these new Swans. Thanks!


  2. #2
    Michael McCulloch's Avatar
    Michael McCulloch Guest

    Default Williams Optics Swan Eyepieces

    On 27 Feb 2005 18:11:52 -0800, willismat239@earthlink.net wrote:


    I will provide some feedback, but keep in mind this is not an
    exhaustive review.

    I bought a pair of the 20mm SWANs. They appear to be well made with
    good coatings, are very lightweight, and have no bright metal in the
    optical path to source reflections. In fact, all the barrel pieces are
    black.

    In my f/5 newt, the EP begins to show softness in the outer ~25% of
    the fov. At the very edge, stars show signficant distortion and cannot
    be focused to a point.

    When I use the EPs with my Denk II binoviewer with a ~1.3x OCS, the
    edge performance is much improved. My estimation is that the 25% noted
    above is decreased by at least half, and star images at the very edge
    are not as objectionable. With a barlow or higher-mag OCS
    configuration, there is even further improvement.

    The AFOV does appear to be close to the advertised 72*, as I did A-B
    comparisons with a Pentax 20mm XW that is 70*. Of course, the Pentax
    is much sharper over the entire fov at f/5 -- and is 3.5x the cost.

    The eye relief of the 20mm SWAN also appears to match the advertised
    17mm. It is quite comfortable and I can see the entire fov even when
    wearing my glasses.

    Therefore, I can say the 20mm EP should perform acceptably in f/6.5
    scopes and slower. I don't think the 20mm SWAN is good performer in
    f/5 or faster scopes (unless you use a barlow and/or OCS) due to the
    edge softness -- the large AFOV isn't very useful in such scopes due
    to the distortion.

    The shape of the barrel is compatible with the Denk SCDs, but you must
    crank the SCD almost completely closed to clamp the EPs.

    I also tried the EPs in my binoviewer at very high power on Saturn and
    the Moon and did not note any objectionable ghost images or
    reflections. Contrast seemed good.

    I have not had a chance to compare contrast performance on faint DSOs.

    I plan to keep the 20mm SWANs and use them exclusively for binoviewing
    because of the light weight, wide AFOV, and excellent eye relief. With
    my various Denk OCS parts and a barlow, I can achieve 5 different
    magnifications.

    YMMV.
    ---
    Michael McCulloch

  3. #3
    clydec@nyc.rr.com's Avatar
    clydec@nyc.rr.com Guest

    Default Williams Optics Swan Eyepieces


    willismat239@earthlink.net wrote:
    1.25"
    with
    (small)
    some


    Willis,

    In addition to Michael's post, if you're a member of Astromart, you can
    check the eyepiece forum where a couple of gents have just posted
    impressions of several different Swan eyepieces.

    Clyde


  4. #4
    Michael McCulloch's Avatar
    Michael McCulloch Guest

    Default Williams Optics Swan Eyepieces

    On 1 Mar 2005 14:05:57 -0800, clydec@nyc.rr.com wrote:


    I read those myself and thought they were accurate comments. I am a
    bit surprised that the 15mm version is reported to have shown little
    improvement in edge sharpness. The eye relief of the 9mm is much too
    tight for me.

    Why not buy 19mm Panoptics for my binoviewer? Well, I have a Portaball
    and the weight is a big issue. Plus, the 13mm eye relief when wearing
    glasses in an issue for me with the Pans. And last, but not least, is
    the matter of $480 vs. $156.

    ---
    Michael McCulloch

  5. #5
    clydec@nyc.rr.com's Avatar
    clydec@nyc.rr.com Guest

    Default Williams Optics Swan Eyepieces


    Portaball


    Do you have the 8" f/6 Portaball? Just wondering. I'm coveting that
    scope as I need to traverse several flights of stairs to get to my
    rooftop to observe. A buddy close by has the 10" Portaball and Saturn
    in a binoview is simply stunning.

    Clyde


  6. #6
    Michael McCulloch's Avatar
    Michael McCulloch Guest

    Default Williams Optics Swan Eyepieces

    On 1 Mar 2005 18:18:53 -0800, clydec@nyc.rr.com wrote:


    I have the 12.5" f/5 model. Using a binoviewer with any Portaball is a
    bit of a challenge, but I believe the SWAN EPs are going to be light
    enough to allow me good results.

    Saturn at 600x through the binoviewers with my 12.5" Zambuto primary
    is also a sublime sight when the seeing conditions permit.

    ---
    Michael McCulloch

 

 

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