SPCC with duoband filter (only Ha and OIII let through)

Paul Mongillo

I struggled with this matter with PCC as well and am optimistic that filters might be added to the new SPCC. However, there seems to be no option for these commonly used filters. When I shoot broadband with a UV/IR cut filter, the graphs are spot on. However, with either the NBZ Nebula Booster or my Antlia Gold Douband, the graphs are pretty scattered or bend away . I have tried setting to narrow band and just changing the band width to match my filters, but no cigar. Is there a solution that I am missing here?  I have watched both of Adam's new videos on this. There seems to be a way to import filter specifications, but it's Greek to me. Thanks.

BlockHead

Paul,

There are a couple of issues. The point with NB filters is that you can obtain the proper ratio of flux (brightness) between them. If you put an NB filter in front RGB filters... this double filtering is kinda crazy. Since your H-alpha and SII will fall into the same Red filter - there is no discrimination. The OIII will fall into bother green and blue pixels to some degree... a degree to which is dependent on filter, sensor and proper metrics of both- which is something you likely do not have with OSC sensors. 

So I am not surprised things are wonky. I suspect you should be able to create a combined R+Ha and a B+OIII and a G+OIII custom response and then use this. I am guessing this would help but you are doing something (by double filtering) that is not really helpful in principle. Yes, it is clever to utilize OSC for NB by using these dual band filters... but it is not characterized sufficiently. 

Perhaps I will show how to hack the filter definitions. It should be trivial to create a rectangle for the NB filters. 

-the Blockhead

Paul Mongillo

Thanks