Well I finally got the Nikkor 200mm F/2.0 onto the mount an took a few images last night.
I images two regions of the sky, the first was Gum15 flanked by Gum17 (lower left) and Gum14 (upper right) and the other was NGC 6334 and NGC 6357 in the same FOV.
This big lens is excellent lens for astro imaging.
Image details: Nikkor 200mm F/2.0 lens set at F/4, Astronomik 12nm Ha filter fitted to the QHY9 CCD camera, 4x1800 second exposure.
Chris, I use a Nikon to T thread adapter which screws on directly to a TS- Services 15mm thick filter draw which in turn is screwed to the QHY9 body once the front nose piece containing the optical window is removed.
Mike/Ross, thank you for your comments. Yes, the Nikkor 200mm f/2.0 has a big piece of glass on the front. If it's clear to night I may try to open up the aperture stop to f/2.8 or maybe even to f/2.0 but I'm not sure what effect this fast focal ratio will have on the narrowband filter. I have heard that the narrowband filters do not work well at these fast focal ratios (band shift?). I also live in a heavily light polluted part of the city.
