The entire filter assembly. In order, from telescope objective side (L) to camera side (R), the optical elements are: 1. Baader UV/IR cut filter (ERF), 2. Collimator Lens (-150mm achromat), 3. Baader 1.25in Halpha 35nm (to block out the blue remaining in the "cyan" Ha narrowband filters), 4. Refocuser Lens (+324mmfl by combined system of -120mmfl and +100mmfl achromats), 5. Two "cyan" Ha filters in kinematic mounts for tilt-tuning. There is also a Borg-Hutech helical focuser on the camera side of the filter assembly.
