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  1. #1
    Bill Vidicini's Avatar
    Bill Vidicini Guest

    Default eyepiece projection setup recommendations?



    I just purchased a small, industrial video CCD camera that I would like to
    use for planetary imaging (it uses a ICX098BL CCD). The camera has a C/ CS
    mount and it was recommended to me to use it in an eyepiece projection
    setup. Using the program called "WhatUSee" it appears that several
    eyepieces with apparent fields of 70 degrees or more in the 8-12mm range
    should do nicely. Pentax was a recommended brand (any other brands?).
    However, I am at a loss as to what brand of coupler I should use to 1)
    attach the eyepiece to the camera and 2) allow an adjustment range from the
    top surface of the eyepiece out to 75mm or so. Also, I notice that some of
    the more expensive eyepiece projection couplers seem to allow the eyepiece
    to be placed within it and then the assembly is inserted into the telescope.
    Is this correct? What is the advantage over the other couplers?

    Thanks for your help.

    Bill



  2. #2
    RMOLLISE's Avatar
    RMOLLISE Guest

    Default eyepiece projection setup recommendations?


    Bill Vidicini wrote:

    Hi:

    I'd forget eyepiece projection. After using these types of cameras for
    the last decade on the Solar System (until webcams came along), I found
    that "negative projection," barlow projection, works best. The best way
    to set up for this is to either buy or fabricate a 1.25" nosepiece for
    the camera (I believe Adirondack Video Astronomy sells 'em). Insert a
    2x, 3x, whatever, barlow into the scope, insert camera into barlow, and
    have fun.

    Peace,
    Rod Mollise
    Author of _Choosing and Using a Schmidt Cassegrain Telescope_
    and _The Urban Astronomer's Guide_

    Like SCTs and MCTs?
    Join the SCT User Mailing List.
    <http://www.groups.yahoo.com/group/sct-user>

    See my home page at
    <http://skywatch.brainiac.com/astroland/index.htm>
    for further info

    For Uncle Rod's Astro Blog See:
    <http://journals.aol.com/rmollise/UncleRodsAstroBlog/>


  3. #3
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default eyepiece projection setup recommendations?

    On Thu, 29 Dec 2005 14:38:50 GMT, "Bill Vidicini" <will@netnet.net>
    wrote:


    Unless you are using this with a very short focal length telescope,
    there is no reason to use EP projection. Start by using the camera
    directly at the focal plane of your scope. Once you are comfortable with
    its operation, you can use a barlow to increase the effective focal
    length of your system. With your camera, your ideal focal length for
    maximizing resolution will be around 3000mm.

    The only adapter you need is a simple C-to-1.25 barrel. You can get them
    from Scopetronix and a variety of other places. No need for a camera
    lens, no need for an eyepiece.

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

  4. #4
    George's Avatar
    George Guest

    Default eyepiece projection setup recommendations?


    "Chris L Peterson" <clp@alumni.caltech.edu> wrote in message
    news:tiu7r1pirq0s67elg2f3njvh1t7t3i6223@4ax.com...

    Actually, I have had the same question on my mind recently, and have often
    read others discussing using a barlow, but was unsure if they were
    attaching the camera to it or if they used it in eyepiece projection. I
    would have answered this question for myself if I owned one. I've been
    considering buying a barlow, if for no other reason than the fact that it
    would give me more magnification options. Now I know for sure how it is
    being used with digital cameras and know that it would work just fine for
    my set up. Thanks, Chris.

    George



  5. #5
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default eyepiece projection setup recommendations?

    On Thu, 29 Dec 2005 15:31:54 GMT, "George"
    <george@wtfiswrongwithyou.com> wrote:


    George-

    Just to be clear, I'm talking about a setup involving a video camera
    which has no lens of its own. Many digital cameras have built-in lenses
    that can't be removed. If you are using such a camera, you need to use
    afocal imaging, which mechanically looks like EP projection (optically,
    it isn't the same thing, but you use the same sort of adapters). With
    such a setup you still need to use an EP, whether or not you also use a
    barlow.

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

  6. #6
    Bill Vidicini's Avatar
    Bill Vidicini Guest

    Default eyepiece projection setup recommendations?

    Actually, I'm one of the owners of a new, uncompressed frame capture CCD
    camera. I was wrong about the CCD... it is actually the same CCD used in
    the Lumenera 075 but this camera is made by Imaging Source. Sorry, I don't
    have its model number memorized. There was another post recently on the
    problems a fellow was having using his Lumenera with a Televue 3x-
    vignetting. Believe it or not, but when I used to use a webcam with the
    Televue 3x, there actually was some vignetting present. I doubt most folks
    notice this, but try the 3x barlow/ webcam combo on the sun (filtered of
    course!) and you'll see the vignetting. Another experiment to try is to
    center Saturn in your scope with the webcam/3x barlow combo, and then move
    Saturn to the edge of the field. Notice the gain dropoff! My conclusion
    has been that a Televue 3x really isn't suitable for webcamming because of
    the vignetting produced, as the other guy found out with the prior post.
    Yeah, I'm being the "squeeky wheel" here, but I need the maximum light
    preferably at all areas of the field of view, not just the center. I did
    find success with 2" sized Powermates though but unfortunately no 3x barlow
    in the 2" size (Televue, are you listening?).

    Therefore, now I'm looking at eyepiece projection. The higher end Televues
    or Pentax should be ideal and according to the WhatUSee program, vignetting
    shouldn't be an issue. Just finding the correct coupler is the challenge.

    BTW, George, to answer your question, I had used a Televue 3x with webcam
    directly inserted into it for quite some time successfully. There is some
    vignetting, as I mentioned above, but this really doesn't become an issue
    unless you decide to switch cameras and have a different CCD.

    Bill


    "George" <george@wtfiswrongwithyou.com> wrote in message
    news:KjTsf.683553$xm3.242453@attbi_s21...



  7. #7
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default eyepiece projection setup recommendations?

    On Thu, 29 Dec 2005 15:58:31 GMT, "Bill Vidicini" <will@netnet.net>
    wrote:


    Bill-

    What kind of scope are you using for you video imaging?

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

  8. #8
    RMOLLISE's Avatar
    RMOLLISE Guest

    Default eyepiece projection setup recommendations?




    Hi:

    Well, good luck. Some folks have made eyepiece projection work using
    fairly exotic solutions like using microscope objectives for
    projection instead of eyepieces, but in my experience, it's a recipe
    for poor images. I'd much rather put up with some vignetting (That
    said, I've never noticed ANY with any webcam barlow combo I've tried).

    Peace,
    Rod Mollise
    Author of _Choosing and Using a Schmidt Cassegrain Telescope_
    and _The Urban Astronomer's Guide_

    Like SCTs and MCTs?
    Join the SCT User Mailing List.
    <http://www.groups.yahoo.com/group/sct-user>

    See my home page at
    <http://skywatch.brainiac.com/astroland/index.htm>
    for further info

    For Uncle Rod's Astro Blog See:
    <http://journals.aol.com/rmollise/UncleRodsAstroBlog/>


  9. #9
    Bill Vidicini's Avatar
    Bill Vidicini Guest

    Default eyepiece projection setup recommendations?


    "RMOLLISE" <rmollise@hotmail.com> wrote in message
    news:1135877279.750945.84170@f14g2000cwb.googlegro ups.com...
    Televues
    vignetting
    challenge.

    Rod,

    If you use a similar setup as I, C8 followed by Televue 3x and webcam, you
    can do a little experiment: some night when you are doing planetary
    imaging, after centering the planet, adjust ra/dec until planet is at one of
    the bottom corners of your screen and note the gain dropoff. It's not much,
    but it's there. A better candidate is a filtered sun and that's when you'll
    really notice it.

    As far as eyepiece projection is concerned, I really don't understand what
    the problem is. After all, if we use say a Powermate, aren't we putting
    almost the same amount of glass between our cameras and scope? I recall Ed
    Grafton using eyepiece projection for nearly all of his great planetary CCD
    images and I recall others, such as Damian Peach, mentioning using it as
    well. I'm not trying to disagree with your opinion here, but have you
    actually tried it using an appropriate setup? Did you use a top of the line
    eyepiece with a suitably wide field and decent coupler (which is what I'm
    searching for)? Why did your images come out poorly? Did the extra glass
    elements cut down the incoming light too much?

    Bill





  10. #10
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default eyepiece projection setup recommendations?

    On Thu, 29 Dec 2005 17:59:13 GMT, "Bill Vidicini" <will@netnet.net>
    wrote:


    Bill-

    I'd say this is a poor setup. With your new camera, that gives a scale
    of 0.19"/pixel, which is far too fine. Your C8 is diffraction limited at
    about 0.6". A basic 2X barlow will give you a scale of 0.29"/pixel- a
    much better match for resolution, and you will also place more light on
    each pixel, helping you get higher above the readout noise floor.

    I see about a 8% dropoff in light at the corners with a similar setup-
    not enough to be very significant. On the other hand, I've never managed
    EP projection without getting a much less flat field.

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

 

 
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