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Old 01-09-2014, 09:17 PM
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Terry B
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Join Date: Mar 2006
Location: Armidale
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Quote:
Originally Posted by Amaranthus View Post
I'm not really sure what you were asking then Philip. Measuring image scale in arcsec/pixel, what I said above is correct - for a given chip, the longer FL will give a higher per-pixel resolution. The speed (f/ratio) determines the rate of photon accumulation per unit area (pixel), not the aperture.

But it seems like you were already well equipped to answer your question, so I suspect you were after something else. Could you re-clarify?
Just to be confusing, this only works for extended objects. For stars that are point sources of light, aperture is more important than f ratio. If the aim is photometry then more aperture means dimmer stars can be measured.
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