Telescope for William Optics binoviewers

[Knighty2112]

As some may remember I got some William Optics binoviewers a few weeks ago. With both my two current refractors (Skywatcher Startravel 120mm f5 & new Altair Astro Starwave 102mm f11) I can't achieve focus with the binoviewers without using the 2xbarlow nosepiece that I ordered up seperately to use as before I received the nosepiece I was using my Celesstron Omni 2x Barlow to achieve focus. I've been toying with the idea of cutting down my ST120 frac to be able to use the binoviewers for wide field views when using, rather that having it 2 x magnified with the Barlow nosepiece, but don't really fancy putting a hacksaw to the tube and cutting it shorter really. So, my question is has anyone who has or previously owned the William Optics binoviewers had/got a telescope where you could achieve focus OK with the binociewers without either having to fit the 2x Barlow nosepiece (or any Barlow), or do any other mods or buy extra equipment to get the widest views possible with them? I'm looking perhaps at maybe a Skywatcher 127mm Maksutov scope perhaps as I believe they have a large amount of inward and outward focus that might be able to help with the binoviewers. I would also consider another frac perhaps, as long the total weight with any diagonal & any EP's would not exceed 5kg as I intend to use it on the Skywatcher Stardiscovery Az Goto mount that I am buying from Dobbie on Friday.

Any feedback for a decent scope to do this would be welcome!  

[avtaram]

I have the WO binoviewer and can achieve focus without using the barlow in my OMC 140 mak, 127 mak and 90 mak. In my refractors to achieve focus I have to use a 1.25" diagonal and the supplied 1.6X barlow screwed into the diagonal rather than it being screwed into the nose piece of the binoviewer.

In my reflectors I can't achieve focus with or without the barlow there just isn't enough inward focus.

Avtar

[Knighty2112]

54 minutes ago, avtaram said:

I have the WO binoviewer and can achieve focus without using the barlow in my OMC 140 mak, 127 mak and 90 mak. In my refractors to achieve focus I have to use a 1.25" diagonal and the supplied 1.6X barlow screwed into the diagonal rather than it being screwed into the nose piece of the binoviewer.

In my reflectors I can't achieve focus with or without the barlow there just isn't enough inward focus.

Avtar

Thanks. Are the 127 or 90mm Mak still available? Only see the 140 on their website? 

[rikroe666]

I have a pair of William optics binoviewers and they work without Barlow or 2x nose piece with my William optic Zenith Star 80mm using all my eyepiece pairs, I also use them with my OO OMC-140 with no Barlows etc.

Out of the two I would choose the William Optics for the wider views and is also excellent on planets.

[Mark at Beaufort]

I think you will find that you will not require the barlow when using a Mak/Cass or SCT. Most refractors require the barlow and as mentioned above it is difficult to get enough inward focus to use binoviewers in reflectors.

With my 4" Astro Tech frac I have been using binoviewers for many years and my focus point with a barlow is about 1 cm from the buffer. I previously owned a 180mm Mak /Cass and I never needed the barlow. I currently cannot gained focus with my 8" Orion VX8.

[Knighty2112]

30 minutes ago, rikroe666 said:

I have a pair of William optics binoviewers and they work without Barlow or 2x nose piece with my William optic Zenith Star 80mm using all my eyepiece pairs, I also use them with my OO OMC-140 with no Barlows etc.

Out of the two I would choose the William Optics for the wider views and is also excellent on planets.

Thanks. Might have to save up to get a Zenith Star, but worth keeping in mind.  

[Knighty2112]

22 minutes ago, Mark at Beaufort said:

I think you will find that you will not require the barlow when using a Mak/Cass or SCT. Most refractors require the barlow and as mentioned above it is difficult to get enough inward focus to use binoviewers in reflectors.

With my 4" Astro Tech frac I have been using binoviewers for many years and my focus point with a barlow is about 1 cm from the buffer. I previously owned a 180mm Mak /Cass and I never needed the barlow. I currently cannot gained focus with my 8" Orion VX8.

That's what I was hoping for. I have a small 70mm frac too which even with the 2x Barlow I can't achieve focus with. No rush to make up my mind which scope I might get, and may perhaps leave it until after Christmas too, but most likely will go with a Muskatov or SCT of some sort.  

[Pingster]

Explore science 102 and 127mm apos work with about 25mm spare in focus with WO binos and 5mm spare in focus with mrk 5 binos. Uss baader prism t2 diaginal and NOT 2in mirror diaginal! ☺

[Knighty2112]

4 hours ago, Pingster said:

Explore science 102 and 127mm apos work with about 25mm spare in focus with WO binos and 5mm spare in focus with mrk 5 binos. Uss baader prism t2 diaginal and NOT 2in mirror diaginal! ☺

Yes, I got a Baader T2 prism diagonal to use hoping that might do, but still no joy.

[Pingster]

Sadly the Altair astro scopes are not binofriendly. They are normal lenght scopes. Hence i bought ES127mm. I too wanted an Altair astro becuase i love the build quality and twist lock eyepiece holders. 

But i choose the ES127mm becuase its binofriendly. What this mean is that the scope is shorter than normal. About 150mm. And the light path of mist binos is avout 115mm hence they come to focus with binos using T2 prism diagonal with baader quick changer.

I dont think you can come to focus with your Altair without using a barlow or... cutting down the tube.

[Knighty2112]

11 minutes ago, Pingster said:

Sadly the Altair astro scopes are not binofriendly. They are normal lenght scopes. Hence i bought ES127mm. I too wanted an Altair astro becuase i love the build quality and twist lock eyepiece holders. 

But i choose the ES127mm becuase its binofriendly. What this mean is that the scope is shorter than normal. About 150mm. And the light path of mist binos is avout 115mm hence they come to focus with binos using T2 prism diagonal with baader quick changer.

I dont think you can come to focus with your Altair without using a barlow or... cutting down the tube.

Great scope, but a little too pricey for me to justify to be able to use my WO binoviewers on, I may have to visit a few telescope showrooms perhaps and take the binoviewers with me to test out in any scopes in store. As the Altair Astro will be my main scope, and the new scope to go on the Goto mount a secondary one I want to keep the cost down to around £300 or so'ish as it will primary just be used for wide field views only. The Skywatcher 127mm Maksutov comes in under that for just the OTA assembly only, so if this scope can achieve focus OK without having to use any Barlow at all with the WO binoviewers then most likely I'll go with this scope perhaps. As I say, not looking to make any quick decisions here, so still open to suggestions.  

[Pingster]

Sadly very few refractors are bino friendly. And if they are you ideally need at least 120mm or you will notice too much diming from binos. And if you have to use a barlow... then 130 is my personal min.

You could try an ES AR127mm. At £500 is close to your budget... ok its a doublet. But i dont think you need to cut the tube on it as i think it has extention tubes like their APOs. But do check with supplier, not that they know any better when it comes to bino viewing most of the time.

But even if you have to cut the tube... looking at the design it seems a simple matter of cutting then redrilling holes to scew back to focuser.

Its a real shame all astro refractors are not all bino friendly by default... surely the manufactures have enough time now to catch up.
 

[YKSE]

13 minutes ago, Knighty2112 said:

 it will primary just be used for wide field views only. The Skywatcher 127mm Maksutov comes in under that for just the OTA assembly only, so if this scope can achieve focus OK without having to use any Barlow at all with the WO binoviewers then most likely I'll go with this scope perhaps. As I say, not looking to make any quick decisions here, so still open to suggestions.  

Mak or SCT are bino-friendly scopes, but they're not wide-field scopes.

[Pingster]

I was going to say the above... using those acopes wpuld be like using your bino in them with x2 barlow... even tho you wont need the barlow... cos theor FL is too long. 

Yiu idearly want an F6.4 refractor... a cheap doublet is an option as you dont feel bad if you need to chop it down.

[Knighty2112]

OK, thanks. I guess what I really meant was to be able to use the EP magnification alone rather than having it doubled by any Barlow in the optical chain to give me the widest fov for that EP size on any particular scope. I know the longer focul lengths of the scope will give each EP more magnification than shorter focul length scopes. 

Are there any shorter focul lengths scopes then that might work with the binoviewers perhaps that will allow me to achieve focus Ok without using any Barlow nosepiece also? 

[Mark at Beaufort]

I had an Altair Astro Lightwave 72ED frac which was a great scope. However, I wanted to use my Lunt 1.25" Herschel Wedge and binoviewers but could not obtain focus even with a barlow.

I was thinking of buying the Altair Astro Starwave 152 but would only consider it if I could use binoviewers.

 

[avtaram]

12 hours ago, Knighty2112 said:

Thanks. Are the 127 or 90mm Mak still available? Only see the 140 on their website? 

I bought the 90 mak from AstroBoot and the 127 and 140 from SGL members.

I think FLO sell the 90 and 127 and OO sell the 140.

Avtar

[Pingster]

Mark im also eyeing up altairs 152... but it wont take binoviewers. Mr Altair listern up and please make your 2017 ranges bino friendly and im sure you would sell more scopes. Idearly they scopes need to be 20cm shorter than normal 2in eyepiece & diagonal focus.  

[Mark at Beaufort]

32 minutes ago, Pingster said:

Mark im also eyeing up altairs 152... but it wont take binoviewers.

Thanks for that helpful info. I was going to the IAS next month where Altair Astro has a stand - I was going to ask about binoviewers and their various scopes. Although in saying that I know that @DRT has the Starwave 152 but can't get focus with his Baader 2" Hershel Wedge but I am sure he said other diagonals were OK. I really wish companies would state whether they are binoviewer friendly either with a barlow or not.

[Stu]

I once had a very nice Orion 80ED which had a split tube so you could remove a section to allow for easy binoviewing. I bought and sold it for around £300 but I've not seen many/any around since.

Pretty sure my Tak would take BVs without a Barlow, but I usually as minimum use a GOC as it corrects for CA produced in the binoviewers. Must try it without sometime soon.

The C925 is excellent with them, but as said, with a Mak/SCT you are not talking widefield scopes.

[Pingster]

As far as i know the [removed word] takes above 80mm take binos and so most APM Loz scopes with have the amazing retracting focuser. Clever germans. And of course all es scopes over 80mm take binos. 

And yes why cant the manufactures state it clearly. ES a clever company dont even say they are bino friendly. How silly. Losing sales.  

[YKSE]

2 hours ago, Pingster said:

As far as i know the [removed word] takes above 80mm take binos and so most APM Loz scopes with have the amazing retracting focuser. Clever germans. And of course all es scopes over 80mm take binos. 

And yes why cant the manufactures state it clearly. ES a clever company dont even say they are bino friendly. How silly. Losing sales.  

I thinks that's about the right numbers. Here's what I can see

WO/TS binoviewer 100mm light path + ca 15mm 1.25" adapter =115mm

Baader maxbright 110mm light path with T2 =110mm

Denk binotron with T2 =127mm

Televue Binovue with T2 =140mm

Baader Mark V with T2 =123mm

With 20mm as safe margin for different EP focus variations, there's should be at least extra 135mm focus travel compare to mono view, for using binoviewer without a barlow or GPC, so testing in daytime, you should focus on a far-far away target (close to infinity focus in night) in mono, if there's at least 135mm inwards focus travel to spare, then you're safe. Otherwise no.

The mostly likely scenario is that a bino-friendly refractor should need an extension tube to reach focus in usual mono view. 

 

[Moonshane]

I suppose it's worth getting a machine shop to cut the tube and make a jointing piece so it can be restored to standard spec if required/sold - although an extension tube would work fine.

I'd get my 120ED cut if required but hope that there's enough capacity with a weak barlow.

[Pingster]

I personally find that 2in extensions tubes are perfectly stiff for getting back to normal single eyepiece length when needed. Thats if i reach for them often now as i binoview 90% of the time. 

[Knighty2112]

3 hours ago, avtaram said:

I bought the 90 mak from AstroBoot and the 127 and 140 from SGL members.

I think FLO sell the 90 and 127 and OO sell the 140.

Avtar

Are you referring to the Skywatcher Skymax versions of the 90 and 127mm Maksutovs here on FLO? I though you meant originally that they where all versions done by OO here?