Saturn & Tethys Shadow Transit 4/20/10

Under good seeing but poor transparency, I was lucky to capture a shadow transit of Tethys shortly after it reached peak altitude. My usual f25 1/15s only gave a poor 50% histogram so I backed off to 7.5fps 1/8s R,G and 3.75fps 1/4s B all at full gain to achieve 75%. Best 800 frames stacked. Tethy's shadow can be seen just over the ring slightly left of center at the top of the first dark band. With my optics newly realigned, my improved collimation really made a difference.

Regards,
Steve

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Here's the Red channel image which shows the shadow better

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