Reviewed by 2 customers
I purchased them to use for astronomy only and they were to be used mounted. A rather strange optical artifact is seen in both barrels when looking at stars or Jupiter in the night sky. I've never seen it in any other binocular that I've used. In the left barrel when focused in on a star like Vega you would see two spikes/flares that extend outward from the star about 1/2 degree each. These are seen at the 10 o'clock and 6 o'clock position. I rotated the binocular to rule out any problems with my eyes, the spikes moved when I rotated the binocular only. The right barrel has the exact flaw; however, it is a mirror image of the left barrel. The spikes/flares are seen at 2 o'clock and 6 o'clock, looking through both barrels merging the images together gives 3 spikes at 10 o'clock, 2 o'clock, and 6 o'clock. I test for spherical aberration and other problems so as far as I can tell the problem are the prisms that are causing the excessive flaring/spiking. I really liked the binoculars otherwise, it was just this issue that made them intolerable for me to use so they were returned.
Great for bird watching and scanning the night skies. Clarity is excellent out to the edges and I like that you can lock the focus. I've had no collimation issues - solid construction! I'd highly recommend a tripod for astronomy.