we will swap the currently used 3.5nm Ha filter on the iDK 20" in Namibia with a 7nm Ha filter soon. We were able to source one such filter from Baader, and I expect delivery to my home in the coming week. I will then ship it somehow down to Namibia. As the Covid crisis, regrettably, went back to full emergency down there I am not sure currently when they will be able to swap the filter, but it should happen within the next few weeks.
This should bring back performance when using narrowband filters. 3.5nm is simply too narrow under such a prisitine sky 😅