Finally the Skywatcher 120ED Pro in Binocular with NO OCS!

[Fedele]

Yes, finally, after many indecisions, I took the big step.

I had verified that the change of the original focuser with a specific one (found after much research and careful studies on back focus) would work. But the expense would have been excessive.
So I took courage and ... sawed off 35 mm, with the help of a telescope builder.
PURE SHOW. With a MAXBRIGHT II, with the T2 32 Prism with 2 "NAso directly in the tube, I now go into focus with all my eyepieces: from Abbe 32 mm, to Ploss TV 25 mm, to Abbe 18 mm, to Taka LE 7.5 , to Baader Ortho 10 mm, to Abbe 6 mm ... etc

I am really really satisfied. Spectacular!

[Fedele]

[F15Rules]

Good job, Fedele!👍😊

It's great fun binoviewing with no OCS or Barlow, at native magnifications..I've always got confused regarding exactly what magnifications I'm getting when an OCS or Barlow is inserted into the binoviewing system.

Also, you can now get nice low power wider fields with objects like Pleiades, the double cluster etc.

Dave

 

[Stu]

Great job Fedele!. You must have been a bit nervous doing that, but well worth it to achieve what you we after. Enjoy it!

[jock1958]

The old Latin proverb “Fortune Favours the Brave” springs to mind here and mightily glad that it’s worked out for you!
Im still in the early days of binoviewing and like Dave @F15Rules says not quite sure what magnifications I’m getting with barlows etc fitted but it’s been fun experimenting. 

[Stu]

31 minutes ago, jock1958 said:

not quite sure what magnifications I’m getting with barlows

That’s always the problem isn’t it? I’ve come to the view that I don’t worry about what mag I’m using, if it works for the target I just enjoy it. It only becomes an issue when trying to communicate what you were doing and what worked! I use a GPC plus a Barcon and various extensions which I THINK give me around x200 but am never quite sure.

[Rusted]

Well done! A nice compact, set-up. 

I have hacked bits off my old Vixen 90mm f/11 to make it more binoviewer friendly.
The problem with GPCs is that they are so far from focus on the front of a binoviewer. 
Due to the long GPL [Glass Path Length] they [often] amplify the image far too much for comfort.
But bung a GPC on the nose of an astro camera and the power is relatively mild compared with many Barlows.
 

 

[Stu]

5 minutes ago, Rusted said:

The problem with GPCs is that they are so far from focus on the front of a binoviewer. 

I use low power eyepieces (25mm) with GPC and barlow to get to high power. Nice big exit lenses, comfortable eye relief and easy to merge images. Works well.

[jock1958]

8 hours ago, Stu said:

That’s always the problem isn’t it? I’ve come to the view that I don’t worry about what mag I’m using, if it works for the target I just enjoy it. It only becomes an issue when trying to communicate what you were doing and what worked! I use a GPC plus a Barcon and various extensions which I THINK give me around x200 but am never quite sure.

Spot on with your analogy in communicating how you used to make things work, all I can say the combinations I’ve used so far have been endless and mind boggling!

For native low power views I reduce back focus with an ultra short clamp & adapter on my Tak FC-100DL in conjunction with a 1.25” Baader prism diagonal with a 2” nose piece. 

If it’s high powered views (more back focus) I’ve been using the 2” visual back that came with my Tak,  Baader 2” mirrored diagonal and the lens off my Baader 2.25x barlow screwed into the BV nose piece or more lately my TV 2.5x power mate. 

Edited May 15, 2021 by jock1958

[Chris]

It must have been terrifying trying to keep everything exactly square when sawing, so I'm glad you had some help with that! Brilliant result, well done, enjoy!   

[Rusted]

4 hours ago, Chris said:

It must have been terrifying trying to keep everything exactly square when sawing, so I'm glad you had some help with that! Brilliant result, well done, enjoy!   

Wrapping and tightening a good length of paper, with a straight edge, around the tube produces a square edge.
Tape the roll of paper to keep it tightly in place. Tape it to the tube if you are of a nervous disposition. 😱
Now try to remember which side of the paper roll you should be sawing. 👴🏻
Finish off with a flat file and/or emery paper glued to a bit of plywood.
I've used this technique with tubes up to 18" diameter.