binoviewer focus in refractor

[inspectapart]

I have a Vixen 102 fluorite which won`t come to focus using my WO binoviewer with my diagonal.(not enough in travel). It works ok staight through, but it can be a bit uncomfortable without the diagonal.

Does anyone know if the Denkmeier 11 system would come to focus using my WO diagonal, or do I need the Denk diagonal as well?

Bob.

[Peter Drew]

I also have a Vixen 102FL which didn't come to a focus with a regular binoviewer until I introduced it to the hacksaw. I've since got a Denkmeier "Big Easy" binoviewer which I've not tried on it but I would expect it to reach focus even without the cutting by way of its OCS system.

[inspectapart]

Thanks peter. ( hacksaw is a bit drastic. did consider this myself, but only for a milisecond !

You think a denk may focus with a diaginal in place then?

Do I need a 2" diagonal?

Bob

[E621Keith]

Have you tried using a prism. Most prism diagonal have shorter light path.

You can also extend the focal point using a Barlow.

2" mirror diagonal have the longest optical path length of all common diagonals, so you definitely don't want to use that.

[SkyGibbon]

Have the same binoviewers and same issue with WO 71z. Unscrewed lens element off a 2x barlow, screwed it on binoviewer nosepiece and works like a charm, only magnified a bit of course.

[Naemeth]

Barlow will do it, so will taking a hacksaw to the tube.

Personally, I'd prefer the barlow, although you will have to put up with higher powered views .

[Stargazer_00]

Check out Siebert Optics in the states. The guy makes all kind of optical light path reducers for a relatively affordable price. I was going to get a Newtonian reducer for the short period of time that I owned a pair of WO BVs.

I realised the amount of compromises I'd need to make and the amount I'd need to invest in quality eyepieces and simply sold the BVs on instead.

[Stu]

Telescope Service are also worth a look. They do quite a few adapters with shorter optical length which may help you reach focus.

Stu

[Mark at Beaufort]

I bought a pair of Skywatcher binoviewers for use with my 4" APO frac and was able to gain focus with the 1.6x barlow. However, I could not obtain enough inward focus on the William Optics SD66 frac.

What I have noticed is that using a different barlow I am able to gain focus on the small WO frac. I have used the Baader Hyperion zoom barlow and this gives me an extra 15/20mm of extra focus capability - link - http://www.firstligh...oom-barlow.html

I also tried out the bottom end of this Baader Classic Q 2.25x barlow at the SGL8 star party and again this gave me extra focusing capability - link - http://www.firstligh...25x-barlow.html

So rather than the hacksaw, or buying a new Denk binos, try and get hold of one of these different barlows to see if they work. Clearly the magnification is going to increase but the use of different low power EPs (25mm ?) might be better than nothing.

Mark

[Space Dragon]

The best chance you have of reaching focus without cutting or using a barlow/OCS is to use the Baader T2 Prism diagonal, it's only a 38mm light path.

You can screw various noses/EP adapters onto it for use with different set-ups but the shortest path would be to use Baader Maxbright binos which attach directly to the prism via a T2 thread.

This is the shortest possible light path possible and the last thing you'd want to do is use the Denk with a 2" diagonal.

This set up would also give the shortest path in your CPC 800 which would minimise the chance of aperture loss.

PS It would be good to be able to edit before 500 posts.

[Stu]

The best chance you have of reaching focus without cutting or using a barlow/OCS is to use the Baader T2 Prism diagonal, it's only a 38mm light path.

You can screw various noses/EP adapters onto it for use with different set-ups but the shortest path would be to use Baader Maxbright binos which attach directly to the prism via a T2 thread.

This is the shortest possible light path possible and the last thing you'd want to do is use the Denk with a 2" diagonal.

This set up would also give

Baader Maxbrights attaching straight to the diagonal is how I do it too, quite a neat solution.

Stu