For Sale:
Williams Optics P-Flat88 field flattener. This is a 1:1 field flattener designed for f5.5-6.0 refractors. Has a 2" barrel (with a 2" female filter thread) on the telescope side, and a T-thread on the camera side for direct connection to your CCD or DSLR T ring. See here for details:
https://www.williamoptics.com/access...ner88_spec.php
Price: $130 posted within Australia (SOLD)
Williams Optics VR-1 violet reducing 2" filter. This filter proved to be very effective at controlling CA when used together with the above field flattener on my Long Perng 80mm f6 achromat. See here for image example:
http://www.astrobin.com/79602/
See here for filter details:
https://www.williamoptics.com/access...r_features.php
Price: $90 posted within Australia (SOLD)