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Message: <blockquote data-quote="Alexis Powell" data-source="post: 1348525" data-attributes="member: 5327">This has been an interesting discussion of potentially relevant theory/hypotheses for understanding the basis for the validity or possible pitfalls of star testing with a booster.  However, at the end of the day, I must admit to harboring a different sort of skepticism (than Ed's) with respect to judging the utility/validity of this practice.  It seems to me that those who regularly use this technique are careful, detail oriented, discerning folks, and that it has been their experience that these tests reliably reveal differences in optical quality among units, and provide some inkling of the bases for those differences (i.e. the particular aberrations involved).  At the extremes, I've not heard of anyone discovering that a seemingly excellent unit was "actually" substandard, or that an obviously flawed unit was "in fact" excellent.  As importantly, it seems that units that are found to be cherries consistently test as such.  I think this has already been done a bit, but unless _all_ boosters have certain biases in common, testing for the practical validity of the practice should simply involve using several different optics as boosters and checking that the results from testing a particular unit do not differ depending on the optic used as the booster.  Maybe Henry, Kimmo, and others always use the same optic as their personal booster, but I don't think so.--AP</blockquote>

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