What’s that noise Fred… Did you hear the Dichroic Beam Splitter calling?
Seriously, it will be the answer to your guiding woes assuming you intend to go longer than 30mins for subs. I can’t imagine why you’d do that now anyway. Your ST8 has an NABG chip so unless you’re using some really narrowband pass emission line filters (like the Custom Scientific 3nm Ha for example) you are going to get blooming within 15-20 mins, right? The benefits in going deep really on work with ABG chips as they bleed photons as the pixel wells begin getting full (typically around 80% mark). Like most CCD cameras, this can be tuned. I know the STL series has a setting you adjust inside the camera to alter the depth, but really I don’t see any true benefits of such tweaks. Of course if you are interested in doing scientific work (say photometry), stay clear of the ABG chips. The bleeding of photos/controlling of pixel well depths can alter the true reading of star values/measurements.