Antlia a Chinese manufacturer of filters has released a range of 3.5nm filters (Ha/OIII/SII) for short focal ratio scopes (F2).
These images are taken with the new QHY600 on a C11HD RASA using the 3.5nm Ha filter.
The 2nd post of this CN link shows an awesome picture of the Horsehead, there is so much detail, that even Alnitak just disappears into the background.
https://www.cloudynights.com/topic/7...faster-optics/
EDIT: I got carried away I did, just realised he has deleted all the stars.