I am testing out some Baader Ultra-Narrowband Ultra-Fast (F2) filters along with the LRGB filters that are also designed for fast optics, so far what I have found is that all filters are parfocal except for the OIII filter, which I am awaiting a response from Thomas Baader on that. But this leads me to ask for a couple of feature requests.
The first would be an option to state if filters are parfocal or not, maybe a filter group where filters belonging to one group are deemed to be parfocal with eachother.
The second would be to allow an “Offset” between the filters, so rather than auto focus, it moves to the offset for a specific filter for example when going from Ha to OIII it knows the adjustment it needs to make on the focuser.
Right now there are only two options, focus on filter change, which is pretty pointless if the filters are parfocal, or do not focus on filter change which is pointless if the filters are not parfocal. However if in this situation where one out of seven filters are not parfocal it would be good to have some additional options.
This exists in sense that SGPro assumes your filters are parfocal. If they are not (mixed branding or you are very precise), then you should define the focus point for each filter. They are defined in an absolute way, but they are, most of the time not read by SGPro in this way. We keep them in absolute terms so that if we need to go to them blind we have a number, but typically we’ll just read the delta and move that much. After you define these numbers make sure to toggle the Auto adjust focus per filter option in the focus tab.
I currently use the “Adjust focus per filter” but that is a waste of imaging time from a perspective of 6/7 of the filters are parfocal and do not need to adjust the focus. I only need to adjust focus on the OIII filter, so being able to group the filters as being parfocal with each other would eliminate that need as you could have an option of “Adjust focus per filter group” for example, where I would have L, R, G, B, Ha and SII in Group 1, and OIII in Group 2 for example