7 May
2010
7 May
'10
9:39 p.m.
Looks nice. But I've always wondered how one calculates the exact focal length of a given setup. I suppose one could just use the manufacture's stated focal length of the OTA. However, once one starts adding accessories to the back like focal reducers, tele-extenders, extension tubes and filter wheels the advertised focal length becomes useless. Thoughts? patrick On 07 May 2010, at 19:28, David Rankin wrote:
Here is an imaging calculator I wrote in flash.
http://rankinstudio.com/astrocalc
If you put in all the inputs it will tell you your focal ratio, arcseconds/pixel, arcminutes imaged height and width, and size of your sensor in mm.
- Any feedback appreciated :)
David