Hi All,
Not sure if this is the right place to post these but I thought I would share some sites that I have found useful. The following links are handy for eyepiece, telescope and astrophotography calculations:
http://www.stargazing.net/naa/scopemath.htm
http://www.astro.shoregalaxy.com/dslr_calc.htm
http://www.myoptics.at/atmlj/stuff/epcalc.html
and the following are good for predicting seeing conditions:
http://www.skippysky.com.au/Australia/
http://realtime2.bsch.au.com/wv_sat....y=&start=&stop=
I hope these can be useful.
Duncan