binoviewer william optics 1.6 barlow

[dobbie]

Hi guys , does anyone know where I can find the Williams optics 1.6 Barlow nosepiece , been looking on web can't seem to find it , is it only sold as as package? As I can't focus without it otherwise , or is they another way to achieve focus regards dobbie .

[brantuk]

I don't know if it's only sold with the BV package - but it's not like a standard eyepiece barlow cos it screws into the nose of the binoviewers. I have taken my 1.6x off and used the bv's with a 2x barlow though and achieved focus easily enough. Hope that helps

(you may have to change the eyepieces to a different size depending on which scope you're using and fov required).

[coulthamst]

If you can't find a Barlow lense element to screw into the nosepiece, the Barlow supplied with many Skywatcher telescopes has an element which unscrews and will both fit and work in the majority ov binoviewers.

[Mark at Beaufort]

 I bought a pair of binoviewers which did not include the 1.6x barlow but I was able to use this magni-max from Scope'n'skies. Here is a link - http://www.scopesnskies.com/prod/astro-engineering/barlow/astrophotography/AC555.html

I use my binoviewers mainly with my 4" Astro Tech APO frac and I need to use this 1.6x barlow to gain focus. The quality is very good. Hope this helps.

Mark

PS - I also on occasions use these barlows from Baader - http://www.firstlightoptics.com/baader-planetarium/baader-classic-q-225x-barlow.html or http://www.firstlightoptics.com/baader-planetarium/baader-hyperion-zoom-barlow.html

[dobbie]

thanks for the replies guys,, will look into all the options ,thanks for the link mark , regards dobbie.

[dobbie]

^{sorted... just unscrewed the end off my spare 2x tal barlow  fits perfect , just need some ep,s now using two 26mm ortho,s at the mo , what ep's are recommended for bino viewers what does everbody else use?}

[brantuk]

I use the WO supplied 25mm wide angle ones mine. I have a pair of TV 16mm plossls but not tried them out yet.

[Mark in Macc]

I use 25 mm TV plossls, the 20 mm WO eyepieces that are supplied with the binos and 15 mm Vixen NLVs. Be careful not to choose eyepieces that are too wide as you might not fit your conk in between. BST Explorers work well apparently.

[Mark at Beaufort]

Dobbie - when I view the Sun through the Herschel Wedge the 25mm plossls are an excellent choice with the Sun almost filling the whole FOV. I have tried to work out the magnification based on the scopes focal length (709mm) + the 1.6x barlow + the extra focal length of the binoviewers (65mm) which comes to 1200mm. approx. This should give me a magnification of 48x and with a 52 degree plossl this should give me a FOV of 1 degree?? However, as I said the Sun almost fills the FOV so my calculations are going wrong somewhere. Its almost as if the binoviewers + the barlow are making the 25mm plossls act like 8mm plossls?

For this reason I mainly use just he 25mm in the 4" frac. If I use the binoviewers in the 180 Mak/Cass then I don't need the 1.6x barlow. I have a  pair of Skywatcher 15mm wide field and a pair of 12.5mm William Optics planetary. Again in theory the 12.5mm should give me a magnification of 216x but it is greater than that.

So my conclusion is if you need to use a barlow to gain focus don't buy eyepieces that are too powerful. I would say a set of 15mm, 20mm and 25mm are the best options.

Mark

[dobbie]

thanks mark for the info , I have two 26mm uo ortho,s  but not tried them yet as my brother has the other one ( which I am in the process of getting it back off him ) it might cost me scones and coffee , I also have a mak/cass  a nextstar 6se , as I am reading your post you don't need a barlow to achieve focus ? .

[Mark at Beaufort]

Dobbie I think you will find that the Nexstar 6SE is a SCT rather than a Maksutov Cassegrain. Anyway the important point is you want need a barlow and the views will be 3D and fantastic.

You need that 26mm EP from your brother - the bribe of scones and coffee will be worth it.

Mark

[Mark in Macc]

Dobbie - when I view the Sun through the Herschel Wedge the 25mm plossls are an excellent choice with the Sun almost filling the whole FOV. I have tried to work out the magnification based on the scopes focal length (709mm) + the 1.6x barlow + the extra focal length of the binoviewers (65mm) which comes to 1200mm. approx. This should give me a magnification of 48x and with a 52 degree plossl this should give me a FOV of 1 degree?? However, as I said the Sun almost fills the FOV so my calculations are going wrong somewhere. Its almost as if the binoviewers + the barlow are making the 25mm plossls act like 8mm plossls?

For this reason I mainly use just he 25mm in the 4" frac. If I use the binoviewers in the 180 Mak/Cass then I don't need the 1.6x barlow. I have a  pair of Skywatcher 15mm wide field and a pair of 12.5mm William Optics planetary. Again in theory the 12.5mm should give me a magnification of 216x but it is greater than that.

So my conclusion is if you need to use a barlow to gain focus don't buy eyepieces that are too powerful. I would say a set of 15mm, 20mm and 25mm are the best options.

Mark

I found the same with my C9.25 SCT. The binos act like an extension tube and I have to re-focus quite considerably, which changes the focal length of the system as the primary mirror moves. I reckon that my 20mm EPs in my binos give a similar mag to a 15 mm EP sitting in the diagonal. It's quite significant. The lowest I use with binos is 15mm, which should give about 150x, but it seems to be closer to 200x.

[Trentend]

On 24/10/2013 at 14:30, brantuk said:

I don't know if it's only sold with the BV package - but it's not like a standard eyepiece barlow cos it screws into the nose of the binoviewers. I have taken my 1.6x off and used the bv's with a 2x barlow though and achieved focus easily enough. Hope that helps

(you may have to change the eyepieces to a different size depending on which scope you're using and fov required).