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Old 11-09-2020, 05:49 AM
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Stonius (Markus)
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Denkmiere Binotron Questions

Any users here?


I'm trying to figure out how you can calculate the biggest possible field of view with a given scope.


So the Binotron 27 has a corrector, which when combined with the lowest power on the power switcher gives a 1.3x boost.


The aperture of the Denks is 45mm. Does that mean TV EP's with 46mm field stops are not recommended? Cnn you use EP's with 2" barrels? I guess you need to be careful the EP's aren't so fat that they are wider than your interpulillary distance too.


But the main thing is, can I just get any EP and treat it like it has a 1.3x barlow in front of it for the purposes of calculation?


Thanks


Markus
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Old 11-09-2020, 01:01 PM
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Rainmaker (Matt)
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The clear aperture of the Denkmeier Binotron27 is 26mm. The 45mm refers to the corrector. You cannot use 2" eyepieces in them. The widest true field will be from something like a Panoptic24mm.

The A45 corrector is useful for scopes such a Newts where the scopes focal ratio is F4 or F5 which means a smaller diameter corrector would actually vignette the incoming light cone.....
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Old 11-09-2020, 01:04 PM
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Quote:
Originally Posted by Rainmaker View Post
The clear aperture of the Denkmeier Binotron27 is 26mm. The 45mm refers to the corrector. You cannot use 2" eyepieces in them. The widest true field will be from something like a Panoptic24mm.

The A45 corrector is useful for scopes such a Newts where the scopes focal ratio is F4 or F5 which means a smaller diameter corrector would actually vignette the incoming light cone.....

Ah! Thank you kind sir!
Makes sense now. So your panoptic 24mm will be more like an 18.4mm when factoring in the 1.3 x corrector, right?



Cheers


Markus
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Old 11-09-2020, 01:07 PM
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Rainmaker (Matt)
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Yes, the actual magnification factor varies slightly depending where in the light path the corrector is placed.

The standard OCS has a clear aperture of 37mm and will work with most scopes. The OCS A45 is really only needed for scopes faster than about F5.
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Old 11-09-2020, 02:53 PM
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Quote:
Originally Posted by Rainmaker View Post
Yes, the actual magnification factor varies slightly depending where in the light path the corrector is placed.

The standard OCS has a clear aperture of 37mm and will work with most scopes. The OCS A45 is really only needed for scopes faster than about F5.

Thank you!


Markus
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Old 12-12-2020, 10:02 AM
Hoges (John)
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I have an earlier Denk which I think is around 26mm clear aperture. I usually use a couple of 26mm 60 degree meade plossl's which work very well and have no vignetting. However, I do get vignetting when I use the various reducer/barlow combinations. My solution has always been to cut a few inches off my scope tube in combination with a very low profile focuser. From memory, I think you need about 115mm back focus or thereabouts. No problem with SCT's or Maks and I think we used it on a Williams Optics 130mm refractor that had enough back focus to compensate. In the pictured six inch refractor, I was able to use a low profile focusser and a wooden adapter plate without needing to shorten the tube.
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