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Message: <blockquote data-quote="mayoayo" data-source="post: 1504695" data-attributes="member: 16781"><p>I Did use the ZEN 8x43 ,on a tripod,for casual astronomy,and my unit showed very sharp stars,No strange shapes or diffraction ..For a real star test you need something like 1x per mm of aperture to see the real resolution..That would need a 5X boost in the ZEN ED..But even at low power,looking at a bright star ,like Sirius,would help you determine if there are obvious problems present.Basically look for any deformity in the circular shape of the Out of focus image of the star,and look also for diffraction spikes in the Focused star.....of course ,when Star testing a binocular,you are only testing ONE particular unit,one barrel at a time..I do Star test every scope I get ,with a little LED light,.I make a pin Hole in a piece of electrical tape,cover the LED with the tape,and look at it from a set distance in my living room,,,!..I am so familiar with the image and characteristics of this "artificial  star",that it becomes obvious if Coma,pinching or astigmatism are present( to a casual level),or to estimate the level of color correction...This,The level of color correction,IS very obvious ,even at low power..As i said..Im not an optics expert,so this is only a casual and fun experiment...</p></blockquote><p></p>