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Merging Problems with Bright Objects

Started by Peter Glus, 06/06/2007 06:47AM
Posted 06/06/2007 06:47AM Opening Post
Dumb question that probably has been asked before -- when I use binos on bright stars, it is impossible to merge images. However, dimmer objects and clusters are perfect. Is this to be expected?
Posted 06/06/2007 11:40AM #1
If you are new to binoviewing it may take some time before your brain "figures out" what merged images should look like. This varies from person to person. I have no problems now, but I did have trouble merging certain targets at first, while others were relatively easy. It's kinda like learning to ride a bike. You are shakey at first but one day you wake up and wonder why you were having so much trouble before.

David E
Posted 06/08/2007 01:30PM #2
As you've been told, practice helps. Other things?

Make sure you're in focus on both eyepieces--that is, adjust the diopter on whichever eyepiece has that adustment until its focus is the same as the other eyepiece. If your binoviewer does not have a diopter adjustment, just pull an eyepiece in or out until its focus is idential to its opposite number and clamp it down.

If your binoviwer does not have self-centering eyepiece holders, you'll need to play around with the setscrews on one of them until the eyepieces are similarly aligned in their holders. Tightening down setscrews may tilt one eyepiece differently from the other eyepiece and cause merging problems.

Play around with the interocular distance setting. Too far apart, especially will make it hard to merge images.

Merging images is easier at lower powers.

Finally, keep after it and you'll be successful (assuming there's not an alignment problem with your binoviewer).

Unk Rod

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Posted 07/04/2007 12:15PM #3
The cheapest Chinese binoviewers are often miscollimated and get knocked out of collimation much easier than the upscale binoviewers. Check them often for proper collimation.

Check to see if images in both EP's are the same. I use terrestrial viewing or lunar viewing to check EP collimation. Sometimes you need to rotate EP's because their optical centers are off. Mark them for correct orientation next time.

I use binoculars more than a telescope anyway, so merging images comes second nature to me. If I can't merge an image, then something is wrong with the binoviewer or EP's.

No binoviewer is perfectly collimated, which is easily seen by viewing the moon and alternately looking through left and right eyes quickly. You will see some shifting of the image at high powers. Image should not shift more than about 5% though. If it changes when you change EP's, then your EP's are at least partly to blame. I order binoviewer pairs from Siebert, or use those EP's made under tight quality control, like the old Celestron Ultimas.

Buy binoviewers that have a self centering eyepiece holder like Tele Vue, Baader, Siebert or Denkmeier. Once you mark EP's that are off center, you just drop them in by your index marks and tighten down and you are collimated.

Start at lower powers if new to binoviewing. Images diverge more as you go up in power. Stay focused on the center of the image. Rolling your eyes around in a binoviewer will cause a newbie a lot of grief most of the time. Make sure your eyes stay centered over BOTH eyepieces. Make sure you have your diopter setting dialed in correctly.