A question about flocal lenghth.

White Rabbit · #1 14-10-2011, 04:57 PM

Hi Guys.

Can someone help me calculate, or should I say can somone calculate for me the focal lenght of my scope please.

I have a refractor that is 714mm focal length but I have a 0.8x field flattner/focal reducer.

Thanks

White Rabbit · #2 14-10-2011, 05:00 PM

Would I be correct in thinking 571.2?

Alchemy (Clive) · #3 14-10-2011, 05:09 PM

Yep sure is.

Neil · #4 14-10-2011, 05:16 PM

I second that.

Barrykgerdes · #5 14-10-2011, 05:23 PM

Tecnically the focal length will be changed by .8x for calculations of FOV but using a field flattener on the focuser will not change the physical length of the focal path by more than a few centimeters.

Barry