wo binoviewer/dob update, interesting discovery

[sunshine185]

Another further testing session with the bv's just now. Equipment used is a wo binoviewer, skywatcher 200p dob, celestron 2x threaded Barlow and a wo1.6 corrector. Up to now I could only achieve focus using the 2x Barlow, simply not enough "in focus" travel for the 1.6 corrector . Using the supplied 20mm ep's and a pair of bog standard skywatcher 25mm ep's, I had some great views of the moon but wasn't even close to fitting it all in the fov. Was just about to pack up when I had another idea, I took the 1.25 eyepiece holder out, the one that comes with the scope, then I unscrewed the 2x Barlow from the bv and screwed in the wo 1.6 corrector. Then I just put it into the focusser on the dob, obviously I had nothing to hold it in place so I just held it firmly with my hand. It was out of focus but not as before, so with my other hand I turned the focusser, I was greeted by a magnificent sight of the moon which fitted quite easily in the fov of the 25mm ep's. I am just wondering now if there is some sort of adapter out there that can go into the dob focusser in place of the 1.25 ep holder that can hold the bv in place at the position which I was holding it.

[Earl]

How much do you need to extend it for?

[sunshine185]

It needs to go further in to the focusser, the 1.25 eyepiece holder that comes with the dob actually unscrews, the bit threat has the 2 screws on comes away from the bit that goes into the focusser. This would be perfect but it has nothing to hold the bv securely.

[Johann von Hesse]

If you move your mirror up the OTA, you will gain the "in-travel" you need.

[sunshine185]

That seems far too drastic, and I am useless at diy.

[Johann von Hesse]

You can always e-mail Siebert Optics or Denk and get one of the optical correctors that will take care of your focus travel. The pic I have posted shows a Siebert Optics OCA lens that will make your binoviewer come to focus when used in your Newt.

[sunshine185]

Found a great solution, and it has only cost 2 quid from Ebay, M2 grub screws!

[electrok]

"Found a great solution, and it has only cost 2 quid from Ebay, M2 grub screws!"

I own the same skywatcher 200, can you please explain the way you did it?, I haven't bought binoviewers yet because of the problems associated with focusing and high magnifications.

[Mark at Beaufort]

I have some binoviewers and with a 1.6x barlow and a 2" - 1.25" adapter I can easily reach inwards focus with my 150 PDS Skywatcher Newt and 10" Skywatcher Flextube Dob. I remove the extension tube and place the adapter straight into the focuser and secure as normal.

I bought the barlow from here -

Astro Engineering AC555 Magni-Max 1.6x thread on Barlow lens

The adapter is this one - Altair-EX 2"-1.25" deluxe adapter (2x clamping screws) :: Adapters - Photo Visual :: Altair Astro

I accept that the views of the Moon and the Planets are incredible.

Mark

[sunshine185]

I don't have any problems with high mags, I can use 5.5mm fine on nights of good viewing. The 1.25 eyepiece holder unscrews so you can screw it in back to front so the tube goes into the focusser instead of sticking out, you take the thumb screws out and replace them with the grub screws, secure the bv into the holder then put this into the focusser, solves the inward travel problems when using the 1.6 corrector on its own, the moon just fits into the fov, there is not enough inward travel to get focus without the corrector, which is a shame, I need another couple of mm to do this, and I cannot afford a low profile focusser. But 12.5mm on the moon and m42 is wonderful. Using a combination of 1.6x corrector and a 2x Barlow I get 5.5mm, 10mm and 12.5mm.

[sunshine185]

I would love to be able to use 20mm on the moon, I am contemplating getting a pair of 26mm, 30mm our 32mm ep's but not sure if they would work.

[perrin6]

Can you turn all the collimation screws the same amount to move the mirror up without changing collimation ?

[electrok]

...secure the bv into the holder then put this into the focusser...

You use the M2 grub screws to secure the (upside down) 1.25'' eyepiece holder to the focuser? ,

or to secure the binoviewer to the 1.25'' eyepiece holder? ,

or both?

Also, which is the (aprox) magnification that 20mm WO eyepieces give you through x1.6 corrector? (i have read that x1.6 is the magnification that this kind of barlow/corrector give when it is attached in an eyepiece, when it is attached in a bino, because of the bigger distance the mag is bigger)

[gooseholla]

Man, I wish some of you would learn to write clearly! Trying to decipher some of these descriptive posts is impossible!

[electrok]

Sorry for my English, greetings from Greece...

[Mark at Beaufort]

Electrok

I have a 1.6x barlow and I have compared the binoviewer magnification with a single eyepiece. When I use my 15mm eyepieces with the 1.6x barlow in the binoviewers they are almost the same (not quite) as a single 8mm eyepiece in the same scope without the barlow.

Mark

[sunshine185]

The grub screws secure the bv in the 1.25 holder.

[electrok]

The 1.25 eyepiece holder unscrews so you can screw it in back to front so the tube goes into the focusser instead of sticking out

I dont understand how you screw the 1.25 eyepiece holder (back to front) to the focuser, i cant find a way to do it

Thank you all, you are very helpful

Ready to order....(my binos)

[sunshine185]

The barrel of the 1.25 holder unscrews from the bit that sits in the focusser, if you unscrew it then turn it round and screw it inback to front, then the 1.25 holder goes into the focusser but instead of the barrel protruding out, it goes into the focusser allowing for more inward travel.

[electrok]

The barrel of the 1.25 holder unscrews from the bit that sits in the focusser, if you unscrew it then turn it round and screw it inback to front, then the 1.25 holder goes into the focusser but instead of the barrel protruding out, it goes into the focusser allowing for more inward travel.

My friend, you are fantastic, i have this scope for 4 years now and never noticed that the barrel unscrews, nor i have read it somewhere (scope manual or other forum)

Thanks so much...

Going to order the WO bino right away...

[sunshine185]

Glad to be of help. Wait until you see the moon using the 20mm ep's and just the 1.6x corrector, you'll be sat there for hours in amazement.

[sunshine185]

P.s, let us know when you get to try them out.

[Adz]

Sunshine thanks for helping us to understand how you are getting them working. Any chance of a picture of it all set up?

Thanks

[sunshine185]

Pics

[sunshine185]

The set up above its when I am using the 1.6x on its own to view the moon, when using high power with the 2x Barlow, the 1.25 holder can be used as normal.