View Full Version here: : Skywatcher Pro ED80 and Binoviewer ??
10-06-2007, 11:08 AM
I'm revisiting a past question now that I actually own an ED80!:D
Thinking of getting a binoviewer for use with this scope. I would use it with a 2" GSO Quartz diagonal (purchase pending!!).
The WO binoviewer with the 1.6x corrector looks like the most economical, with the Burgess optical/University Optics my 2nd choice as both units come with EPs. Denks just are too pricey.
I have read that there is a problem with these units coming to focus.
What would I need to rectify this?
Extension tube? Barlow? Remove diagonal - although that don't sound too comfortable!?
If I had to use excessive magnification from say a barlow lens to reach focus, would this defeat the purpose of having the binoviewer in the first place. All comments/ experiences/ links greatfully received as Google searches don't yield too much relevant info.
Cheers in advance
10-06-2007, 03:12 PM
Can't speak about the other brands as I have not owned or used them.
I do have a Denkmier "Big Easy" which I regularly use with our Skywatcher Pro ED80 and a Bintel 1.25 inch diagonal.
The "Big Easy" package comes with an "OCS" (I think it stands for Optical Correction System or something similar) which can be used to modify magnification factors...it may also help bring things to focus (??)...
I just know that it works and I have not had any problem bringing things to focus.
The ED80 scope with Binoviewers make a nice little set-up for the moon, planets and "easy" double/multiple star systems...it is not so "spiffy" on DSO...too little aperature but Orion Neb sill looks great!
I have also used these Binoviewers with my Discovery Dob...balance is a bit tricky but the views are quite nice.
10-06-2007, 10:13 PM
Do you think the shorter light path of the 1.25" diagonal plays a role in reaching focus?
Cheers and thanks for the advice
11-06-2007, 02:17 PM
Sorry, but I have no idea if the different diagonal has any impact or not or if there is some other factor (like the OCS) involved...
The choice of the "smaller" diagonal was purely a functional one as all that I have are 1.25 inch eyepieces. I figured I would "save" a small amount of money on what is for me a "fun" scope to look at moon and planets (mostly the moon).
There are a few knowledable souls over at Cloudy Nights in the Binoviewer group...you might try reading/asking there.
11-06-2007, 04:10 PM
thanks - i've been trawling the net (including CN binoviewer forum) for any info on ED80/ Binoviewer combos.
There's surprisingly little for such a popular scope - perhaps there's a clue there!! seems the budget binoviewers have problems reaching focus on the ED80, but not a problem for the costlier Denks:sadeyes:
11-06-2007, 08:45 PM
Hi Doug, the lens of your scope will focus at a given distance behind the lens and that's where you position the eyepiece to achieve focus. When you put a binoviewer in the diagonal you're extending the light path by 4 or 5 inches so the scope's objective lens is focusing inside the body of your bino. To push the objective focal point out to the bino eyepiece holders you can use the corrector/barlow supplied with the bino. If that doesn't push the focal point out far enough you can use a 2x barlow lens instead which gives something like 3.5x magnification. 20mm eyepieces with your scope and a barlow is still only going to give a little over 100x, so you won't have a problem with mag being too high for the objects you'll be looking at.
If the barlow still didn't allow you to achieve focus you might need to use a 1.25 diagonal. Another possibility that I haven't tried would be to unscrew the lens from a 2 inch GSO 2x barlow and screw it onto the front of your GSO diagonal. I use one of the chinese bino's (stellarvue) with my ed100 and they work with both the supplied corrector or a 2x barlow. I hope there's some useful info there for you.
12-06-2007, 07:08 AM
Thanks for the information Tony
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