William Optics binoviewer ,Lunt 35dx and a small frac....

[Fish]

Today thanks to FLO my William Optics binoviewer arrived, thanks yet again for the next day delivery .

Main use for these will be in my Evostar on the Moon, but as a bonus I was hoping to use them in my grab and go scope a WO ZS 66sd and my little Lunt. Searching on the net came up with nothing conclusive except that the Lunt would be a no....

I won't go into the unboxing or the quality of the items as they are perfect, the only minor thing is the 1.6 Barlow only has one protection cap and is too big ?

Out into the garden armed with everything that may help in focusing in my small scopes, various Barlows etc. After quite some time (even removed my Lunt focuser at one point )focus was achieved . At this point I'm looking through one eyepiece only and the magic combination is a 2.5 power mate and the supplied 1.6 Barlow . At this point I would add that the weight and the length of the power mate mean that you have to be careful not to have any disasters , I used two hands on the bins and found them very comfortable

I have the stock 20mm eyepieces , a 1.6 Barlow , 2.5 power mate this is pushing the 35mm of the Lunt and I'm thinking that this is going to be a fail....

Time to take a look with two eyes... WOW... What a shock, the view is a little soft as it always is when pushing the magnification but the view is fantastic. The only way to describe it is its like sitting 6 foot away from a wide screen TV with a large sun in the middle.

A Large filament was visible on the SW of the disc and I could see it standing off the disc in 3d . I then quickly swapped back to my single 15mm TV plossl to compare , the filament I had just seen was only just visible now ,just a flat brownish line ,even though the image was very sharp. Back to the binoviewer and filament still there in all its 3d glory. The level of detail is so much higher with this combo, but it should be less. I don't understand how , obviously two is better than one. The sun looks so much bigger through these but you can still see all the disc, it even seems to make the sweet spot bigger???

Next it was the turn of my Zenithstar 66 , again the only combo that would get focus was the same as the Lunt. I had a look around at some daytime targets and even at this magnification everything was very sharp. Looking forward to being able to have a look at the moon, night shift this week so will have to wait.

Looks like I now have to get another set of TV plossls :-) ....

So WO binoviewer will focus in a 35mm Lunt ,you just need a power mate.

[Joseki]

I really want a WO binoviewer.  Mainly for lunar with my Helios 120 frac.  I might make myself wait for Christmas though.

[JED-E3]

If you have the 2.5x powermate to T-adapter you can get a female T thread adapter that screws into the WO binoviewer, that might allow you to reduce the optical path enough to get rid of the 1.6x barlow.

James.

[NGC 1502]

Nice write up, thanks 

One thing - you mention the possibility of a larger sweet spot with the Lunt 35.

Mine is the basic version L35 with B400 blocking filter. What I find ( with regular mono viewing ) is that at higher power, the sweet spot covers a larger proportion of the field of view, than at low power. I'm thinking that's because I'm viewing just the central portion of the image formed by the optical system.

Regards, Ed.

[Fish]

If you have the 2.5x powermate to T-adapter you can get a female T thread adapter that screws into the WO binoviewer, that might allow you to reduce the optical path enough to get rid of the 1.6x barlow.

James.

Thanks for that James, I will look at doing that if 25mm eyepieces don't drop it enough. In saying that I'm very happy with it as is .