spacepilot
Well-known member
I was looking for a way to test collimation of my binoculars that doesn't require me to look through them. Frankly, I can't detect any image separation using the common methods by looking at terrestrial objects. Looking at stars might yield more definitive results, but I don't have a tripod. Then I found this, using the Sun as the collimator and measuring the position of the Sun's images to calculate angles of misalignment.
http://sites.google.com/site/rchamon/home/sun-images-method-for-collimation-of-binoculars
I just carried out the simplified version (section 4.1), which doesn't require a tripod. I asked my wife to take pictures of the Sun's images, and later measured the misalignment angles in the computer file. It turns out that, out of the two pairs of 8x that I tested today, one has a 11' vertical and 6' horizontal (convergence) misalignment, the other is spot on vertically and misaligned horizontally by 16' (convergence). Figuring in the magnification, both pairs are well within the tolerances listed in the link above and Ed Z.'s post on Cloudy Nights. That explained why I couldn't see the misalignment before.
The simplified test is really easy to do. For roofs, I think it is simple enough to carry out even in the field by trying to align the Sun's images with the shadows of the barrels. The test may be a little harder harder for porros because the eyepiece shadows might not stand out. Either way, I found the quantitative results this test gives very helpful. Now, if only there were a similarly simple and straightforward way to test my diopter setting :smoke:.
I did a search on BF and didn't find a thread discussing this method. Has anyone tried this before?
http://sites.google.com/site/rchamon/home/sun-images-method-for-collimation-of-binoculars
I just carried out the simplified version (section 4.1), which doesn't require a tripod. I asked my wife to take pictures of the Sun's images, and later measured the misalignment angles in the computer file. It turns out that, out of the two pairs of 8x that I tested today, one has a 11' vertical and 6' horizontal (convergence) misalignment, the other is spot on vertically and misaligned horizontally by 16' (convergence). Figuring in the magnification, both pairs are well within the tolerances listed in the link above and Ed Z.'s post on Cloudy Nights. That explained why I couldn't see the misalignment before.
The simplified test is really easy to do. For roofs, I think it is simple enough to carry out even in the field by trying to align the Sun's images with the shadows of the barrels. The test may be a little harder harder for porros because the eyepiece shadows might not stand out. Either way, I found the quantitative results this test gives very helpful. Now, if only there were a similarly simple and straightforward way to test my diopter setting :smoke:.
I did a search on BF and didn't find a thread discussing this method. Has anyone tried this before?