An Astrodon Continuum filter is a 5nm narrow band filter not centred on any emission line. It just records star intensities.
Here is the OIII data with the Continuum data subtracted.
https://www.flickr.com/photos/343863...n/photostream/
Here is the NII data ditto
https://www.flickr.com/photos/343863...n/photostream/
Can anyone spot the obvious PN? There are quite a few more that were hiding in plain sight.
Sorry I took so long to get back but I got distracted.
The RH200 at 600mm and F3 is fast but here is what the RGB looks like.
https://www.flickr.com/photos/343863...n/photostream/
My major aim in imaging is to look around and image dim stuff and areas that have been neglected that have interesting dim objects. With the wide field of the RH200 3.5x3.5 degrees I can cover a fair bit of sky.
This may give others with longer focal lengths some interesting objects to image at greater detail. Bert