[gregbradley]

Superb choice of imaging setup Bert. I was eyeing off that 200mm Riccardi Honders F3. I don't quite understand why its bigger brother is so expensive in comparison to the 8 inch.

Proline should be 65mm shutter standard, check with Greg at FLI though to be sure.

50mm square filters are what I use and they are fine.

I use Astrodon Gen 11 filters and original Astrodon Gen 1 5nm Ha O111 and S11. They all work fine. Astrodon Gen 1 filters gave bad reflections with 16803 chipped cameras which show up the optical imperfections of the scope quite badly.

Astrodon Gen 11, latest Baader (I would check them out thoroughly though to make sure they don't still have some reflection issues - not certain on this point but I do recall a cople of images on the net where reflections were still not good enough). Astronomik latest generation.

Basically the filter needs the antireflection coatings otherwise you will get nasty reflections as every scope with this large of a chip needs a flattener and the reflections bounce back and forth.

PMX should be great.

I did read one negative comment though about the 200mm Honders though. Best to check it out for yourself. I was unsure how someone could comment as they are new to the market. A friend of mine Bob Fera images using an Officina Stellarvue 14.5 inch RC and his images are great.

Being a new scope though I wonder if all the little bugs have been sorted. AP and Massimo Riccardi worked together to help produce the AP version which is a slightly different design and a bit slower at F3.6. It has a separate mirror, the Massimo one has a mirror on the back of the corrector plate like a Mak Cass I believe.

It would be worth checking out as it appears to be an awesome cutting edge scope. Main issues would be whether it has a large enough corrected circle for the 16803 which is 52mm, also how bad the vignetting would be. Do they publish a vignetting diagram? I get heavy vignetting with my CDK17 but it flat fields out largely then I usually have to do some gradient processing to take it the rest of the way. Most scopes show some vignetting with this large chip. I can post you flats of various scopes to show you what I mean. You would be shocked by some of them!

As far as bandpass width of narrowband that is probably its own debate. I use 5nm, I have used 6nm and 7nm. I had Baader 7nm Ha and I got a bad filter -it was defective, but looking past the black spots defect it seemed good.

I find though even with 5nm I can't really image with the CDK17 if the moon is to close by. It lets too much in and there is no contrast to make an image with. 200mm F3 - the F3 will affect the bandpass anyway. There is an article about this on the Astrodon site. As I recall it makes your 3nm wider because of the light ray angles in the fast scope hitting the filter at such an oblique angle.

Have you considered a FLI Microline 16803? It weighs a lot less, cools only 3 or 4C less than the Proline and has the same features.
The Proline has a USB hub (2 extra USB slots) and 2 extra power outlets but the USB hub like most USB hubs can jam with some other equipment and still require a separate cable (my ST402 often seems incompatible with the Proline). Tilt in the focuser at F3 will be ciritical to achieving round stars to the corners.



Greg.