I think this is from the oberworks home page (www.bigbinoculars.com [?])
Home Page >Product User Guide > Binocular Collimation
Oberwerk 56mm-70mm Binocular Collimation
A binocular is actually a pair of refractor telescopes joined together. The alignment between these two telescopes is called "collimation". Proper collimation is critical to a binocular's performance, and the user's viewing enjoyment. The brain can do a remarkable job of compensating for poor collimation, but has more trouble doing so on the night sky due to the much lower amount of visual information. For this reason, good collimation is especially critical for astronomical binoculars. Here at BigBinoculars.com, every binocular we ship is first tested (and adjusted if necessary) for proper collimation. Because collimation is occasionally lost due to rough handling during shipping, and because some individuals need to adjust collimation for their own eyes, we have decided to put these collimation instructions on our website for our customers usage.
Surprisingly, collimation adjustment is easiest to perform in daylight. Collimation can be quickly be checked by viewing a house at about 100-200 yards. It is best to do this outdoors, as viewing through a window can cause distortion from diffraction. Begin by focusing on an object with horizontal and vertical lines, such as a door or window on the house. Alternate viewing with the left and right eyes by gently closing one eye at a time. Alternate eyes about once per second. Relax your eyes as you do this so they are not compensating for misalignment. Notice that the object will move somewhat as you alternate eyes. A slight amount of horizontal movement (to the left with the left eye, and to the right with the right eye) is normal, and is desirable. Excessive horizontal movement, or any amount of vertical movement (see pic at right), should be corrected.
An even more accurate test for vertical collimation is to focus on a distant, yet distinct, horizontal line, such as a roofline or gutter. Slowly move your eyes back from the binocular until they are about 4 inches away, while maintaining the view of the roofline in eyepieces. Let your eyes relax and focus more on the image at the eyepieces rather than through the binocular. Even a slight vertical miscollimation will now be readily shown as a difference in position of the horizonal roofline (see pic at right).
Now that we can determine collimation problems, how do we correct it? The secret is the porro prism adjustment setscrews hidden under the rubber armor close to the edge of the prism covers, as shown in the picture at the lower right. You'll need a rather narrow jewelers screwdriver to adjust the setscrews. Use it to carefully lift the rubber covering to find the setscrews. If you don't stretch the rubber any more than necessary to reveal the setscrews, the rubber will snap back to original position when you are done. The setscrews may be rather difficult to move, and some downward pressure may be necessary to prevent stripping of the setscrew slot.
The setscrews move the image in the same direction as the screw. So when screwing the right setscrew inward (clockwise as viewed from above), the right image will move downward and also to the left. Unscrewing the right setscrew (couter-clockwise) moves the image upward and also to the right. The left setscrew works in the same manner for the left image. Turning the setscrew clockwise moves the image in the left side down and to the right, counter-clockwise moves it up and to the left. Typical minor miscollimation can usually be corrected by tightening just one setscrew. The key is to determine which side needs to move, and how much it needs to move. Make adjustments in very small increments, moving the setscrew as little as possible, and frequently checking progress by using the above visual tests. To correct for horizontal miscollimation, where excessive left-right difference exists between the left and right views, requires moving both setscrews. Move them both inward to push the images downward and toward each other. Make sure that you end up with perfect vertical alignment. A slight amount of left right movement between the two images is acceptable- in other words, the left image should be slightly to the left, and the right image, slightly to the right. Under no circumstances should the images cross over to the opposite direction- this will quickly cause a headache if viewing for any length of time.
Using the above techniques should allow you to obtain perfect collimation. The ultimate test is to view the night sky. Bright objects such as Jupiter should be well merged, with no double images. Perfect collimation will allow you to view for extended periods with no eyestrain or headaches.
40mm-70mm |80mm-150mm |Tripods |Mounts |Accessories |Specials |Gift Ideas |Spec. Chart |Mission |News |FAQ |User Guide |Comments |Contact
© 1999-2003 Oberwerk Corp.
On Friday, October 3, 2003, at 09:49 AM, Richard Tenney wrote:
The pair sounds like it was out of collimation. I once found an article on a website out there that tells you how to adjust the collimation on these binos, but certainly you shouldn't have to collimate a new pair. I'll see if I can hunt it down, or if anyone on the list knows where to find that article, please respond. Meanwhile, good luck with the next pair.
Rich
--- Richard Brady <rhbstargazer@networld.com> wrote:
I got a pair of the 15x70's and had to send them back. It showed everything in double-vision. When I looked at star fields with first one eye and then with the other, the two didn't match up. So I sent them back for exchange. Hopefully the next pair (if they aren't out of stock yet) will be OK. Star images weren't pinpoints, but they were small.
Richard Tenney wrote:
FYI Although the Sportsman Guide 15x70 Galileo binoculars were out of stock when I sent the last emailing out about them, a list member checked back today and they are in stock again. The total with ground shipping is $82.45
Chuck Hards also informs me that he still has 2 sets of Solar Filters for these babies leftover from his last e-bay auction; $25 a pair (it's a steal).
-Rich
__________________________________ Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. http://search.yahoo.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com
http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
__________________________________ Do you Yahoo!? The New Yahoo! Shopping - with improved product search http://shopping.yahoo.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy