Binoviewer collimation

[gliderpilot]

Help, I have been using a WO binoviewer for observing but noticed that it has recently lost its collimation. I have no idea how this happened as it is kept within a case in the shed and therefore does not travel anywhere. The collimation is not bad but if I relax my eyes, stars become double and lunar craters are more numerous. It is passable at low magnifications with the supplied 20mm eyepieces but easily noticeable when using my celestron zooms at high powers.

While trying it out last night on the waxing moon, I noticed that if you put the moon just outside the field of view so that the light path is illuminated, the right hand eyepiece’s prism edges are clearly visible so it has obviously become misaligned. The left eyepiece remains evenly illuminated implying that the prism is still true.

Unfortunately the WO 2y warranty has expired so I need to post it back to get a quote for repair. I guess it is too much to expect an optical instrument to last more than 2 years? Oh well ….

Thanks for reading, Mark

[philsail1]

Hello Mark,

Forgive me for asking - but you do know your WO Binoviewers can be collimated by turning one of the barrels in which the eyepieces fit?

I have a cheap pair of "Astro Engineering" binoviewers, and they sometimes go out of collimation - even though they are kept in a box of their own in the house.

I think that it is quite amazing how these binoviewers do keep their collimation so well - especially when one thinks that "collimation" in binoculars is so critical a part of their construction. (The prisms in most pairs of "ordinary" binoculars are held in place very securely).

If you have already tried re-collimating your binoviewers, then do forgive me for suggesting it!

Best wishes,

philsail1

[gliderpilot]

I didn't know that, Phil, so thank you for the pointer. I know that the individual focus is adjusted when turning the eyepiece barrels so would you mind explaining how to adjust the collimation - googling didn't turn up any instructions?

Thanking you in advance,

Mark

[philsail1]

Mark,

On my "Astro Engineering" binoviewers there are two adjustable rings on each barrel. One is for ajusting the focus of each eyepiece, and the other for adjusting the collimation of each eyepiece. On mine, the bottom knurled ring adjusts the focus, and the top one slackens to allow me to turn the eyepiece within the barrel as I'm looking through the binoviewers (say at the Moon or Saturn), until the image merges into one.

I find that I only need to move one eyepiece to achieve this. Once the eyepiece is in the right position, I "lock" the adjusting ring.

If I change the 26mm eyepieces, to use a set of 10mm, I have to collimate all over again, so I tend to leave the 26mm's in, and use a 2x Barlow.

Williams Optics are a quality manufacturer of optical goods, so I would think there will be facilities to collimate. Have a study of yours - I'm sure you will see how to do it.

Regards,

philsail1

[gliderpilot]

Will check this out this evening after work, thanks, Phil.

Mark