It occurred to me yesterday that perhaps I was being unfair to Zeiss here, as this thread has quite a few views. People may get the wrong impression regarding quality control and thus reluctant to choose a new Zeiss if the opportunity is there.
I regret putting the optical test results here since they were in fact, a bit crude. My view at the time was that if the results were horrible (150/D), I would retest more precisely and evaluate my options. So let me tell you, if you want a precise idea of the optical qualities of your scope, what not to do, as I did:
-- don't perform star tests when low pressure systems are still passing through. I did on a night of fast moving partly to mostly cloudy skies. Star test when you can, on a clear night with little to no turbulence
-- don't use a cheap, zoom bino as your multiplier to achieve magnifications of 100x or more. I did. You risk incorporating any optical flaws of the bino into your results.
-- don't perform resolution tests where any haze is present. I did. Make sure it is a clear, sunny day, with little wind and before any heat haze presents itself. Keep your scope in the shade and the target well lit.
-- make sure your scope is thermally equilibrated before testing. Talking at least 2 hours here. Fortunately, I did this previously when testing.
So why did I perform such crude tests? Impatience, really. But like I said, I knew what I was doing wasn't precise, so I knew the scope was better than I was reporting. I believe I failed to communicate this clearly in my post, though.
I visited a scope shop yesterday that is familar with me. They allowed me to borrow an eyepiece doubler for a few days so I could be more precise with these tests.
I performed a star test on my scope with the doubler on a near perfect, crystal clear night last night. Before, I could detect no astigmatism at 75x on just the scope. With the doubler, there was still no hint of astigmatism present at 150x. It may be that the astigmatism I detected previously was due to the cheap binos I was using as a magnifier. Undercorrection to spherical aberration was still present, but I could at least see diffraction rings on both sides of focus.
This morning was a perfectly clear, wonderful morning for resolution testing. Again with the doubler, I could detect no astigmatism when looking at the usaf chart. This time, I got a resolution of 1.46 arcseconds, which amounts to 124/D. A far superior result than previous. Needless to say, I won't be exchanging this scope, but I will be repeating these tests to verify.
I'll post some digiscoping details later in the week, but at 20x, this is a good combo with the s95. I'll likely be getting some astro eyepieces for this scope for more eye relief, once I can sift out which ones will work best with the adapters available. The baader hyperions I know will work well (with baader adapter) but I'm also looking at perhaps the vixen lvw series as well. Both offer 20mm of eye relief with the baaders offering a slightly larger field of view.
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