Thanks ALL. Why the question? Well I've just spent money (too much of!) on an IDAS MBZ nebular filter for OSC cameras. I already had an IDAS NB-1 filter but I wanted to do a comparison between the two.
This is the first stage of the comparison as these images were captured through an Altair Wave Series 115 APO Triplet @ f7 with a Planostar x1 flattener, via the above filters to an ASi533 OSC camera cooled to -12°C gain to 100.
Capture via SG Pro, PHD 2 with multi star guiding, Processing in PI duplicating each process stage.
Image A is via the NBZ filter, image B is via the NB-1 filter.
Stage 2 will be using the same filters on a different subject with the RASA 8 to see how they handle the f2 image cone (I may not use A & B references next time...)