difference betw big and small pixel size

shoelevy · Post by **shoelevy** » Sat May 29, 2004 1:55 pm

hi all....how does pixel size affect the performance of a ccd camera for astrophotography?

tanguan2001 · Post by **tanguan2001** » Sat May 29, 2004 2:39 pm

Shoelevy,

For a given no. of pixels, smaller pixels give a smaller field of view.

Also smaller pixels are less sensitive.

TG

shoelevy · Post by **shoelevy** » Sat May 29, 2004 4:48 pm

so wat's the advantage of having a camera with smaller pixels?

tanguan2001 · Post by **tanguan2001** » Sun May 30, 2004 8:47 am

The idea is to match your telescope to your CCD. If you are doing DSO, the ideal match is to have each pixel cover 2 arcsec of sky. Much less and you lose sensitivity, much more and you lose resolution. Most of our seeing results in stars covering more than 2 arcsec because of atmospheric turbulence, so less than 2 arcsec per pixel doesn't give you more resolution.

For planets you'd aim for less than 1 arcsec per pixel, becuse the short exposures and possibility of freezing good moments of seeing may give you that resolution - if your optics are up to it.

You can get the formula for matching pixel size and focal length from the S&T website, I believe - a couple of excellent articles on matching F to CCD's. Try this as well.

http://www.licha.de/AstroWeb/articles_f ... 3?iHowTo=9

TG