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Old Burgess model, difficult to merge image, is it just me?

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#1 Moxized

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Posted 03 December 2020 - 03:06 AM

So around 2008 I purchased these Binoviewers from Burgess without eyepieces. They have sat in my eyepiece case a long time and figured I'd find a pair of lenses or decide on a second for my current collection, but never did, Until this past week, decided I'd just try a cheaper pair just to try things out. I picked up the svbony 20mm gold bands after reading others enjoy them in binos. I received them and checked each eyepiece alone and they appear alright.

 

So I tried it out on the moon with the Bino and I cannot get an image to merge for my eyes. I look with the same eye through each eyepiece and they appear Identical to me. But some strange reason my eyes refuse to merge the two as I play with the Bino's eye width.

 

I searched on here and found posts about this style I have, and read that the three screws are used for adjusting to help merge eyepiece images, I've found this to not be the case for mine, first the right eyepiece holder is snug compared to the left, even swapping the eyepieces around. Still even removing all the screws and messing around with any play in the eyepieces I see no benefit or change to the image. 

 

The only way I can get the image to merge is putting pressure on the eyepiece holders, pressing them outward, this will merge the image. 

 

Is it just my eyes? Is this common with these older models? Is there other collimation methods I have not been able to find?

 

Appreciate any advise!

 

PXL_20201203_062115958.jpg



#2 Rutilus

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Posted 03 December 2020 - 04:09 AM

I have a pair of these. It could be that the prism has come loose or is not glued in the correct position.

When I first got my pair, the prism glue was white, over time in turns grey and starts to crack/break.

You can inspect the prism by simply sliding the black outer cover downwards.

My pair have a production date on the inside. The glue in my pair had started to crack, so I repaired it

with modeling putty.

Here is a photo. 

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#3 Rutilus

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Posted 03 December 2020 - 04:35 AM

p.s. When I first got my pair, I had to focus using just one eyepiece, then I rotated the eyepiece holder of the other side and

I could see the two images start to merger together.  I find that adjusting the screws that hold the eyepieces in makes no difference

to merging the images together. 


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#4 Eddgie

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Posted 03 December 2020 - 09:57 AM

Back to basics.  Check your IPD.  To do this, position your head over the binoviewer and with one eye closed, and one eye open, put the open eye over the eyepiece and acquire the view. Now, blink that eye close and the other one open. If you do not see the field perfectly centered in the view of the other eye (vignetted), rotate the BV in the holder if it is high, low in that eye, and fold the hinge in or out if the field is cut off in one of the other direction.  Repeat this blink back and forth until the view is exactly the same in each side with no vignetting around the outside of the field.

 

Next, if your eyepiece has undercuts, check that when the nylon screws contact the undercut, that they are hitting completely in the groove. You can measure, or you can just use a visual inspection.  Watch each eyepiece as you screw the nylon screws in. If there is an interaction, you may see one or both of the eyepieces kind of tilt up slightly somewhere.

 

Alternately, you can look at something low in the sky and just place the eyepieces into the holder without screwing them down and see if the image merges. If it does, then try tightening the screws to see if it shifts on one or both sides.  If it does, then the eyepieces are tilting in the holders causing the merge problem. 

 

There is always the chance that the unit is not collimated, but I would not mess with it until you check these other things. 

There are also other methods you can use to check alignment and you can search on them on the forum if neither of these things is the problem. 



#5 Moxized

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Posted 04 December 2020 - 01:11 AM

I have a pair of these. It could be that the prism has come loose or is not glued in the correct position.

When I first got my pair, the prism glue was white, over time in turns grey and starts to crack/break.

You can inspect the prism by simply sliding the black outer cover downwards.

My pair have a production date on the inside. The glue in my pair had started to crack, so I repaired it

with modeling putty.

Here is a photo. 

Thank you! This is the kind of response I was hoping for.

 

I gave a good palm/wack to the black overs and off they came.  I have no date on mine, but do see the construction within. The epoxy on mine is solid, no cracks or play. I don't want to tweak that. I just ended up putting it all back together and tested again on the moon, I put considerable pressure on the eyepieces after both were focused. It seems to be holding and remaining merged after I pushed very hard on them. I guess that will work for now. I don't think I will invest more into this. If I press hard enough and it stays that's good enough. Soon as I have guests around to try and see if it works the same or better, maybe I'll sell this off. I dunno. Its neat on the moon, but not sure it will be worth the hassle and effort on other sights.

 

Thanks again for the help!

 

Best regards!



#6 Moxized

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Posted 05 December 2020 - 08:20 PM

I just want to follow up having more use last night. I discovered I have an easier time with DSO than I did on the Moon. I looked at the double cluster and had no problem merging the view, and enjoy for a good bit. I then tried on M42 and also had no issue merging. When I tried again on the Moon, I immediately had trouble, any turn or movement had one of the eyepiece blacking out, I had to really fuss about with the spread and press out on the eyepieces to get a merged image.

 

This makes me wonder if my pupil dilation has a play in this? Something bright as the moon surely is shrinking them, could that factor in why it's hard to merge viewing the Moon?

 

Anyway, I really enjoyed viewing clusters with this, I'll probably keep them around just for that.

 

Best regards!




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