Binoviewers help

[tooth_dr]

Hi all

Looking some advice. I received a new pair of SW BVs a few days ago.  I tried them out this evening on my 12" dob on the moon, Saturn and a few stars.

I used the 2x Barlow that came with it (to get focus) and my pair of 26mm EPs. I then moved onto my 15mm EPs.

I can easily merge the images but they aren't naturally aligned. So when I look with one eye at a time the left image sits diagonally above to the left of the right one. The last time I noticed this was on my Pentax binos which I sent back to Pentax and they collimated then. The problem disappeared. 

Ive tried rotating the EPs and loosening the locks, all this makes it worse. If I physically push the left (or right) EP I can get the two images in the same place.

Is this the norm? I'm worried I will get a sore head or tired using these for more than a few minutes.

 

Thank you in advance.

[Louis D]

Undercuts are killing your alignment.  Push down hard on each eyepiece as you tighten them into their collets to maintain vertical alignment.  Alternatively, fill the undercuts with pinstriping tape or find a pair of eyepieces without barrel undercuts.  I have the same issue with my Arcturus BV.

[tooth_dr]

4 hours ago, Louis D said:

Undercuts are killing your alignment.  Push down hard on each eyepiece as you tighten them into their collets to maintain vertical alignment.  Alternatively, fill the undercuts with pinstriping tape or find a pair of eyepieces without barrel undercuts.  I have the same issue with my Arcturus BV.

Hi Louis. Thanks for the reply.  None of my EPs have undercuts. 

[tooth_dr]

[Moonshane]

Sounds daft  but here's some things to consider:

Don't use your binos when you are tired or have had a drink (red wine even a little seems to affect my ability to merge)

Are the binos parallel with your face? Sometimes I find a small rotation helps

Ensure you adjust the IPD to best fit

None of this may apply of course but just reflect my experiences 

[tooth_dr]

1 minute ago, Moonshane said:

Sounds daft  but here's some things to consider:

Don't use your binos when you are tired or have had a drink (red wine even a little seems to affect my ability to merge)

Are the binos parallel with your face? Sometimes I find a small rotation helps

Ensure you adjust the IPD to best fit

None of this may apply of course but just reflect my experiences 

 

Thanks Shane. I found all the things you have mentioned (bar the drinking as it's a school night!) did affect my view. But even with most precise facial alignment they are still out. Maybe I'm just being too fussy for cheap binos?

The box of these took a fair battering before I received them so I've been given the opportunity to try or send back. I'm just afraid of keeping something knocked out a bit or perhaps they are all like this?

[Moonshane]

I found that on moon and sun merging and alignmet came immediately and easily.  With planets it took a bit of practise.  The problem is you don't have the luxury of time as if you wanted to return them I presume you are on a deadline. The damage to the box looked bad but the metal on them is soft and thin. Maybe they are out of alignment but as I say I struggled for a while on small high power objects. Difficult decision. 

[tooth_dr]

Hard to know indeed. I'm going to try on the sun again (if it comes out) and if it's good then I'll just keep them as that was my main reason for buying. It's hard to describe how far out but maybe if you imagine Saturn in the right EP, then there is a gap the size of Saturn to the top left for the left eye view of Saturn. If that makes sense. 

[Louis D]

Try them during the daytime on familiar objects.  If you remove the 2x element, you should be able to focus quite close because the binoviewers act like an extension tube.  If you can't merge a brightly lit scene, there's little hope of merging a dot (planet) in a black field.

[Cosmic Geoff]

My budget binoviewer came with a pair of short barrel 32mm Plossl that merge perfectly, but the pair of 20mm Plossl (one with undercut) that I put in it would only merge with some fiddling around. I suggest therefore that the eyepieces are the problem.

[tooth_dr]

2 minutes ago, Cosmic Geoff said:

My budget binoviewer came with a pair of short barrel 32mm Plossl that merge perfectly, but the pair of 20mm Plossl (one with undercut) that I put in it would only merge with some fiddling around. I suggest therefore that the eyepieces are the problem.

I've four pairs of eyepieces (none have undercuts) and I've tried two pairs so far and it happens with both 26mm and 15mm. I'm guessing it'll be worse with 9.7 and 6.4mm too.  I'll try the others but I'm not optimistic.  What you are saying though is that they should merge perfectly? I think I might be too particular. 

[Cosmic Geoff]

58 minutes ago, tooth_dr said:

 What you are saying though is that they should merge perfectly? I think I might be too particular

They should merge properly, without effort, like with regular binoculars.  Your unit might have gone out of alignment (as binos do). Does the misalignment stay put or move with the eyepieces?  OTOH I wonder if sticking in a pair of standard long-body eyepieces is sufficient to obtain proper alignment.

If your supplier is any good they may offer advice or swap the unit.

[Louis D]

On 8/1/2017 at 10:14, Cosmic Geoff said:

They should merge properly, without effort, like with regular binoculars.  Your unit might have gone out of alignment (as binos do). Does the misalignment stay put or move with the eyepieces?  OTOH I wonder if sticking in a pair of standard long-body eyepieces is sufficient to obtain proper alignment.

That's right.  That's how I discovered it was my eyepieces causing the misalignment.  While watching through both eyepieces, I rotated each one in its diopter corrector.  It was plain to see that the planet I was trying to merge rotated around the field instead of staying in one place.  If I loosened the locking collet and merely held the eyepiece against the collar with my finger and thumb, the image would stay put.  That's when I realized I had to cram the eyepieces with undercuts into the holders while tightening the collets to avoid tilting.