Aperture vs. magnification

Boy, the new scope has brought up all sorts of new questions....

I was under the impression that the amount of useful magnification was in proportion to the aperture, up to a fixed limit imposed by the seeing.

But my new 16" SCT seems to take more magnification than my 8", even when the seeing is limiting both to less than the 8's maximum. I had about Pickering 6 skies the other night, and the 16's image was fine at 360X, breaking down at 530X, and complete mush at 800X. Now, I didn't have the 8" set up the same night, but from memory, in similar seeing, I'd get the same results with the same eyepieces -- but since the focal lenght is 1/2, that would equate to OK at 180X, breaking down at 265X, and mush at 400X.

Am I suffering from wishful thinking (and a flawed memory), or is the limit imposed by the atmosphere also somewhat proportional to aperture?

-- Jeff.

Am I suffering from wishful thinking (and a flawed memory), or is the limit imposed by the atmosphere also somewhat proportional to aperture?

-- Jeff.
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I think how the seeing affects the magnification depends on a number of factors but in general scopes/conditions are rated in terms of "magnification per inch of aperture."

jon

Jeff, I think the key is when you said "Now, I didn't have the 8" set up the same night...". Without a direct comparison it's all subjective. Bad seeing on one night is not the same as bad seeing on another night. It can even change minute-to minute. To make the comparison valid you need to do a side-by-side comparison.

Happy testing!
Doug

Maybe I'm missing something here but in case you havn't noticed you have a VLFT. (very large telescope). If you are absolutely idling along at 20x per inch you are at 320x. Apply some throttle and you really get somewhere. Unless it is raining outside you should be able to get 20 per inch. This is why the guys love the big dobs. Correct me if I'm wrong.

Harry