Jerry Hubbell - Explore Scientific VP Engineering
On Sat, Nov 9, 2019 at 10:16 AM, Jennifer Shelly wrote:
Additionally I am having a hard time finding the correct spacing for the FF/FR as my search results have yielded anywhere between 55 mm to 65 mm.Hi Jennifer,
We use the 3-inch 0.7x FRFF on the 6.5-inch ES 165 FPL53 ED APO CF scope (with a Moonlite focuser - I think they are the best) in the MSRO and it works pretty well. The scope is F/7 and with the FRFF it is f/5.2. The design spacing is 55 mm which is what we use. Our imaging train is a QHY163C camera with QHY FW-S and the FRFF. It's pretty flat in the middle but the field curvature starts to increase towards the corners when using larger chip cameras.
Vice President of Engineering
Explore Scientific, LLC.
jrh at explorescientific.com
1010 S. 48th Street
Springdale, AR 72762
Author: Scientific Astrophotography: How Amateurs Can Generate and Use Professional Imaging Data
Remote Observatories for Amateur Astronomers: Using High-Powered Telescopes From Home
Mark Slade Remote Observatory (MSRO) IAU MPC W54 Equipment
Mounts: ES PMC-Eight G11 + Telescope Drive Master (TDM)
Scopes: ES 165 FPL-53 ED APO CF, ES 102 FCD100 ED APO CF
Cameras: QHY174M-GPS + FW, QHY163C
Misc: 3-inch 0.7x Focal Reducer Field Flattener, Filters: Luminance,
Red, V-band Photometric, Diffuser, 200 lpmm Spectral Grating
Software: MaxIm DL 6, Cartes du Ciel, Astrometrica, AstroImageJ, AutoStakkert!