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Good eyepiece pairs for binoviewing

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#1 ajkrishock

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Posted 18 April 2019 - 06:58 AM

All,

 

I recently picked up a Celestron binoviewer for use with my 127 mm Mak-Cass and my CPC 1100. So far, I have a pair of 26 mm TeleVue Plossls (circle-R's) and a pair of older Orion 35 mm Ultrascopics. I'm looking for a higher-power pair of eyepieces now, and I'm looking for some recommendations. The Plossls and the Ultrascopics are limited to a field of about 50 degrees, and they work very well. I have a set of Panoptics for my larger scope, so I was thinking of getting another 19 mm Panoptic, but will the 68 degree field vignette? What would your choice be?

 

Thanks



#2 ngc7319_20

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Posted 18 April 2019 - 08:02 AM

The clear aperture on the Celestron bino is about 20-21mm.  The field stop on the 19mm Pan is 21mm.  So the field stop should still have about 50% illumination -- slightly dimmed but not noticeable -- it should be fine.  One thing I don't like on the 19mm Pans is that the eye relief is starting to get pretty tight.

 

I've started experimenting with a pair of Baader Morpheus 17.5mm eyepieces.  These have about 20mm of eye relief.  I like them so far, but it is still too early to report. If you search the binoviewer forum for various eyepiece names, you should be able to find some reviews.

 

The Nagler 13mm T6 are nice for binoviewing.  Reasonable eye relief and very wide view.  Thats probably my favorite in the 10mm to 15mm range.  Much below that you are probably better off adding a Barlow lens.

 

Another idea would be to get some thread-on Barlow-like lens you can put on your bino.  Just double the power that way, and the 35mm Ultrascopics become 17mm, etc.  I've not tried it, but this Burgess screw-on 1.9x bino lens is $10.  Seems worth a try.  There are other similar products around...

https://www.burgesso...er-19x-oca.html


Edited by ngc7319_20, 18 April 2019 - 08:11 AM.


#3 ajkrishock

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Posted 18 April 2019 - 08:12 AM

The clear aperture on the Celestron bino is about 20-21mm.  The field stop on the 19mm Pan is 21mm.  So the field stop should still have about 50% illumination -- slightly dimmed but not noticeable -- it should be fine.  One thing I don't like on the 19mm Pans is that the eye relief is starting to get pretty tight.

 

I've started experimenting with a pair of Baader Morpheus 17.5mm eyepieces.  These have about 20mm of eye relief.  I like them so far, but it is still too early to report. If you search the binoviewer forum for various eyepiece names, you should be able to find some reviews.

 

Another idea would be to get some thread-on Barlow-like lens you can put on your bino.  Just double the power that way, and the 35mm Ultrascopics become 17mm, etc.  I've not tried it, but this Burgess screw-on 1.9x bino lens is $10.  Seems worth a try.  There are other similar products around...

https://www.burgesso...er-19x-oca.html

Interesting idea. My last experience with Barlow lenses (about 20 years ago) has been that they double the power, but at the expense of sharpness and a reduced field of view. I've always found that the image is degraded somewhat. Is that still the case, or is my recollection outdated?



#4 nicoyenny

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Posted 18 April 2019 - 08:18 AM

I use a pair of 17.5mm Morphei (?) eyepieces almost exclusively on the binoviewer. With a 2X barlow, sharpness suffers on dimmer objects. Moon is no problem, planets are great too. 



#5 otocycle

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Posted 18 April 2019 - 08:22 AM

I sold my pair of 19mm Panoptics and went with two 16mm ES68s instead.   Lighter weight and more comfortable distance between eyepieces.  

 

16mm ES68 field stop is smaller than 21 mm.


Edited by otocycle, 18 April 2019 - 08:24 AM.


#6 ajkrishock

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Posted 18 April 2019 - 08:38 AM

As a side note..

 

Anybody know why every eyepiece explorer scientific lists on their website is advertised as "waterproof"? Is that really a thing? That strikes me as the dumbest marketing strategy imaginable. What's next? Buoyancy? A built-in compass? The ability to check your e-mail?


Edited by ajkrishock, 18 April 2019 - 08:39 AM.

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#7 ngc7319_20

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Posted 18 April 2019 - 10:22 AM

Interesting idea. My last experience with Barlow lenses (about 20 years ago) has been that they double the power, but at the expense of sharpness and a reduced field of view. I've always found that the image is degraded somewhat. Is that still the case, or is my recollection outdated?

 

IThere are many Barlow lenses now using ED (extra-low dispersion) glass which we did not have 20, 30, 40 yrs ago.  

 

Barlow lenses have improved.  Essentially all are achromatic now, and some also use ED (extra-low dispersion) glass.  Back in the day many were just a singlet lens.

 

Some of the "bad reputation" was probably not deserved.  If you take an image with bad seeing / poor collimation / poor optics / etc. and then double the power -- of course it will look blurry.

 

The field of view will still be reduced just because the power is higher.  If you use a 2x Barlow ($10?) on the binoviewer with your 35mm Ultrascopics, you get 17.5mm (twice the power) with the same 50(?) degree apparent field of view.  If instead you got a pair of 17.5mm Morpheus eyepieces ($478) you would have a wider apparent field of 72 degrees.  


Edited by ngc7319_20, 18 April 2019 - 10:24 AM.


#8 munirocks

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Posted 18 April 2019 - 02:19 PM

Depending on the scope, a barlow might actually improve the view if it puts the focus point back into the optimum range for which the telescope was designed.



#9 munirocks

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Posted 21 April 2019 - 02:31 AM

As a side note..

 

Anybody know why every eyepiece explorer scientific lists on their website is advertised as "waterproof"? Is that really a thing? That strikes me as the dumbest marketing strategy imaginable. What's next? Buoyancy? A built-in compass? The ability to check your e-mail?

If you have a long dewey night the equipment can actually end up soaking wet, so being sealed against moisture is a useful property.  



#10 Ed D

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Posted 21 April 2019 - 07:47 AM

Try using barlows  with your eyepieces.  I use Plossl pairs from 25mm to 17mm in my WO bino along with 2x and 3x barlows, especially my Maks.  I find that using a barlow with larger focal length eyepieces gives me easier merging and more relaxed view compared to shorter focal length EPs giving equivalent magnification.

 

Your 26mm and 35mm EPs barlowed 2x should give you good magnification, about as high as is practical in your 127mm Mak.  I can't comment on the CPC 1100 because I never owned or used one.

 

I binoview planets and the moon, so have never felt any need for wider field eyepieces.  My WO bino and Plossls work fine for what I do.

 

Ed D


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#11 25585

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Posted 06 May 2019 - 01:10 PM

I changed from 17.5 Morpheus to Nikon NAV SW 17.5 as the latter are smaller, lighter, and have more eye relief. 



#12 REC

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Posted 06 May 2019 - 02:27 PM

All,

 

I recently picked up a Celestron binoviewer for use with my 127 mm Mak-Cass and my CPC 1100. So far, I have a pair of 26 mm TeleVue Plossls (circle-R's) and a pair of older Orion 35 mm Ultrascopics. I'm looking for a higher-power pair of eyepieces now, and I'm looking for some recommendations. The Plossls and the Ultrascopics are limited to a field of about 50 degrees, and they work very well. I have a set of Panoptics for my larger scope, so I was thinking of getting another 19 mm Panoptic, but will the 68 degree field vignette? What would your choice be?

 

Thanks

A pair of 19Pans would be great. I keep thinking about pairing up mine, but I have already have two pairs of 20mm EP. A cheaper was would be a pair of ES 20mm 68*




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