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Old 04-07-2012, 02:35 PM
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LightningNZ (Cam)
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Join Date: Oct 2011
Location: Canberra
Posts: 952
Bill - No, it hasn't changed your aperture at all. It's only changed your FOV. That's why APS-C sized chips have a so-called "magnification factor" for any lens attached to them - the field of view is reduced by that much and spread over all your pixels.

For photometry the bucket size matters a lot as it is one of the main ways to make sure you have a wide dynamic range (and hopefully good linearity over that range). Given that the whole point of doing CCD photometry is that you get photometry over a wide field then with a big dynamic range you have more comparison stars to work with.

Hope this helps,
Cam
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