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Favorite binoviewer barlow/glasspath combos?

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#1 betacygni



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Posted 27 July 2020 - 07:10 PM

I’ve been experimenting around with different barlows/telecentrics and glasspaths, mounting them in different ways to achieve different magnifications or more compact setups. Just wondering what everyone’s favorite combinations are, how they are mounted, and resulting approximate magnification factor? Seems like there are an overwhelming number of possibilities with all the different options out there.

#2 Eddgie



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Posted 27 July 2020 - 07:51 PM

My favorites are the Baader GPCs and the Televue Bino Vue 2x amplifier.  All of these are excellent. Now it is hard to have a favorite because each one has a specific role.  I use the 1.7x in my Lunt 80 solar scope, and I use the Televue Bino Vue 2x in my dob for planets. The Bino Vue amplifier would give too much power in the Lunt to get a full disk with the zooms I use, and the 1.7x would not give enough light path saving for the dob.


The 1.7x GPC in the Lunt is a custom mount. It is mounted directly into the top of the Lunt Blocking Filter with a 3D printed spacer.  This was necessary to further shorten the light path so I could maintain the fully illuminated circle as large as possible (before this, the fully illuminated circle was about 4mm and after the change, it was 5mm, and the sun disk is about 5.3mm, so that was in important change).


The Televue is connected to a Burgess BV that has a T2 adapter on it.  This allows me to reach focus in the dob and in my 106mm Apo, which I use for solar white light with a Baader wedge. 


The 1.7x GPC gives 1.5x, and the Televue Bino Vue 2x is a bit less than 2x I think but it is pretty close. I don't use it with the Televue Binoviewer, but I am going to assume that in the Televue binoviewer it gives 2x. 

#3 Solar storm

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Posted 28 July 2020 - 11:09 AM

For planets in my 11" dob, the APM 2.7x coma correcting barlow is top notch.  You can unscrew the barlow element and place it in whatever configuration you want.

#4 Jeff B

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Posted 28 July 2020 - 02:12 PM

For my refractors I really like the Baader 1.25X and 1.7X GPCs.  They do what they advertise they will do and do it very well with my Baader MK V and Zeiss/Levatic viewers , and even work great with my Denks with the right adapter.  I just wish there was a power switch device for them like the Denk Power Switch system.  Speaking of which, that's my favorite system for my Denk viewers. 


For my newts, it's the Denk OCS/Power Switch system.  I love three different magnifications at my finger tips and the system is highly corrected with my Denk viewers.


For my cats (SCT's and Mak's) , I chronically use the Denk system, again, because of its great flexibility for multiple magnification selection with the slide of a switch.



#5 Shorty Barlow

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Posted 28 July 2020 - 04:42 PM

I just have a bog-standard WO bino.




I just have the WO 1.6x and 2x nosepiece Barlows. I also have a TS Optics 2.6x nosepiece Barlow. I'm not sure who manufactures it. 



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#6 doug mc

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Posted 28 July 2020 - 08:31 PM

For planets and luna i found it best to use an amplifier beyond 2.5x. This allows the use of longer focal length eyepieces for more comfortable viewing. The OCS i use is a Siebert 1.25x model. With it i can get the stated 1.25x and by placing the the barlow element on its own in the nosepiece of my bino, it delivers 2.8x. I can't fault it optically.

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#7 noisejammer


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Posted 29 July 2020 - 02:35 AM

Hmm - another 'it depends' question.... The numbers refer to my 150mm f/7.3 refractor.


Deep space & general lurking


no correctors + Masuyama 35mm  31x & 4.8mm exit pupil

1.25x GPC    + Masuyama 35mm  39x & 3.8mm exit pupil

no correctors + Vixen 22mm LVW  50x &  3.0mm exit pupil

1.25x GPC    + Vixen 22mm LVW  62x &  2.4mm exit pupil

no correctors + Delos 14mm          79x & 1.9mm exit pupil

1.25x GPC    + Delos 14mm           98x & 1.5mm exit pupil


At this point I can use a 1.25x GPC with the 10mm Delos, 6mm Delos or 5mm XW for wide field which takes me to 275x and 0.55mm exit pupil.

This is surprisingly useful on clusters and globulars.


When the seeing is really good ....

Tak 1.6x + 1.25x GPC + 16mm ZAO II   136x & 1.1 mm exit pupil

Tak 1.6x + 1.7x   GPC + 16mm ZAO II   186x & 0.8 mm exit pupil

Tak 1.6x + 1.25x GPC + 10mm ZAO II   220x & 0.7 mm exit pupil

Tak 1.6x + 1.7x   GPC + 10mm ZAO II   299x & 0.5 mm exit pupil (almost exclusively lunar)


This takes my scope from a very comfortable view sweeping more than 2 deg to as high power as makes any sense in a 6".

If it matters, I install bat wing eye guards and usually employ an observing hood.


If warranted, I'll install an atmospheric dispersion corrector after the Tak extender.

#8 25585



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Posted 29 July 2020 - 04:09 AM

Celestron Ultima 2x & Nikon 1.6x.

#9 Shorty Barlow

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Posted 29 July 2020 - 06:48 AM

Oh, I forgot to mention my favourite. Probably the 1.6x.

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