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Thanks Rodney!
I have to admit that my experiment was just a long standing idea that someday I would test out the barlow this way. It sat in a drawer for many years after reading about it on the AP website. Obviously Roland C knows of what he speaks, so the idea was intriguing. With all my issues with my large heavy KAF16200 camera, while Josh was busy making numeroues adapters and corrections, the opportunity presented itself.
After the fact I was pointed to Russ Crowman's MTF webpage. The numbers are very interesting. Whilst some years back it was common practice, I believe, to recommend an imager like the KAF8300 or KAF6200 for an OTA with a focal length of around the 1 meter mark, advice certainly seems to be shifting in the direction of what would have been considered over-sampling.
Take a look at the two comparisons below. The first shows my TEC180 at f7 with the KAF16200 CCD. It appears to be seriously under sampled. Then just adding a smaller pixel size camera, the IMX571 nearly perfects sampling. The barlow completely wipes away the under-sampling and provides quite a lovely image scale to boot.
Now, I'm back setup with the KAF6200 CCD and wondering if I'll be satisfied with it!
P
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