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My other thread called "Prism Diagonal Anti Chromatic Aberration Effect"
has such bad choice of words that some readers may misunderstood what I mean. Of course I didn't mean that a prism diagonal can cancel the chromatic aberrations of an achromat. What I mean to say is. Given a light cone with zero chromatic aberration (just for the sake of example since many will agree no objective lens has zero chromatic aberration). Does the prism diagonal introduce chromatic aberrations to the light cone and to what degree. Again I'm asking this because I don't notice any chromatic aberrations when viewing thru a prism diagonal and a binoviewer but wondering if the amount is so small that only the image overall color is lessen which doesn't make the violent fringe noticeable. And also what really do compensators (such as AP Glaspath Compensator) actually do to the light cone to remove what little chromatic aberrations is produced in the prism and binoviewer (which is not noticeable to sight). optidud |
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And also what
really do compensators (such as AP Glaspath Compensator) actually do to the light cone to remove what little chromatic aberrations is produced in the prism and binoviewer (which is not noticeable to sight). Prisms introduce primary color (not the same as the secondary spectrum of an achromat) plus spherical aberration. The amount of these errors is proportional to the prism optical path length. In Binoviewers this optical path length can approach 4 inches, so the errors are not trivial. The glaspath compensator in the Baader Binocular Viewer was designed to cancel both primary spectrum and correct the spherical aberration. Another way to minimize these errors is to use very long focal ratio scopes with the binoviewer. The way it is done is to add a 3x barlow ahead of the prism set, so that the Binoviewer "sees" a long focal length beam. If you prefer to use a Binoviewer without that much magnification, you will have to limit yourself to low powers where these errors are not so noticeable. Roland Christen |
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Right now. I can't detect any
fringe of any color in a binoviewer when used in an f/8 apo scope. What Binoviewer are you using? Does it have a built-in 3x Barlow? If it does not have this Barlow, then it will disperse the light slightly - well known law of optics. Whether you can see it or not depends on your local observing conditions and how well your eyes respond to the visual spectrum. Some people cannot see color fringing, even in short tube achromats. For other people, the same scope will show screaming purple color fringing. Roland Christen |
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I bought the Televue Binoviewer but didn't get the 2X corrector. And
I was wondering whether to get it. When used in a 4" f/8 apo, I can't detect any color fringing at 53X even at bright daytime tests. Also do you or anyone knows how to connect the AP 1.25X glaspath compensator to the televue nosepiece via some kind of adapter? I don't need the 2X capability of the TV corrector, just the 1.25X magnification of the AP Glaspath compensator. btw.. what are the primary color that can get affected, you mean all colors such as green, blue and red, all of them will be dispersed? How can one detect the dispersion. I'd like to know what image quality improvement to expect if I get the 1.25X glaspath compensator. optidud (Chris1011) wrote in message ... Right now. I can't detect any fringe of any color in a binoviewer when used in an f/8 apo scope. What Binoviewer are you using? Does it have a built-in 3x Barlow? If it does not have this Barlow, then it will disperse the light slightly - well known law of optics. Whether you can see it or not depends on your local observing conditions and how well your eyes respond to the visual spectrum. Some people cannot see color fringing, even in short tube achromats. For other people, the same scope will show screaming purple color fringing. Roland Christen |
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I bought the Televue Binoviewer but didn't get the 2X corrector. And
I was wondering whether to get it. When used in a 4" f/8 apo, I can't detect any color fringing at 53X even at bright daytime tests. That does not surprise me. You won't see color at that low magnification. Also doyou or anyone knows how to connect the AP 1.25X glaspath compensator tothe televue nosepiece via some kind of adapter? The Televue unit was not made for this device. It was made to be used with its own Barlow. Roland Christen |
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Thread | Thread Starter | Forum | Replies | Last Post |
Prism Diagonal Anti Chromatic Aberration Effect? | optidud | Amateur Astronomy | 12 | July 18th 03 05:25 AM |
Prism Diagonal Anti Chromatic Aberration Effect? | optidud | Amateur Astronomy | 23 | July 16th 03 04:51 PM |