Article: Calculating Focal Length from Plate Scale

iceman (Mike) · #1 10-04-2007, 07:36 AM

Hi all

Anthony Wesley (Bird) has written a fantastic article titled Calculating Focal Length from Plate Scale. It's a must-read for every planetary/lunar imager.

You can read the article on the IceInSpace Projects and Articles page, or directly by clicking the link below:

Calculating Focal Length from Plate Scale

Thanks to Anthony for contributing the article to IceInSpace. If you'd like to submit a review, article or other content to IceInSpace, please contact me.

iceman (Mike) · #2 10-04-2007, 08:51 AM

Article uploaded.

JonBosley (Jon) · #3 29-08-2008, 06:02 AM

Thanks for this! I believe a lot of imagers have the wrong focal length.The correct length is to the CCD. According to my system I was imaging Jupiter the other day at F15 (C11 F10 + 1.5x barlow) but with the flip mirror & image size I knew it was more then this. I applied Anthony's plate scale and it was F20.2!
From this you can take your correct focal length and divide by your pixel size to get your Arc/pixel.

Jon Bosley