[Atmos (Colin)]

About two months ago or so I bought a Sigma Art 85mm F/1.4, it had some QE issues in regards to the auto focuser. Had it out under the stars to see what it was like optically and it had some zonal errors at F/2.8 and F/4, star shapes moving in different directions across the frame. Decided to get a replacement due to the auto focuser motor, seemed that if the focus motor made it though QC the optics seemed to have as well.

Well yesterday afternoon I picked up its replacement, took a couple of months but OMG it is sharp. Sadly I last 1/2 of my data last night due to the Q setting on my Nikon D7200. I know I cannot use the Mirror Up setting with an intervalometer but I was hoping that the Q setting (designed to be quiet, slows down the timing between mirror up and exposure) would relax any potential mirror shutter, and it did, but also only saved every second exposure for some reason.

This is 44x120s of Rho Opt with a Nikon D7200, Sigma 85mm F/1.4 @ F/2.8. Haven't done any calibration as of yet, just wanted to see what would show but I'm planning on getting another 6 hours or so tonight so I'll get all of the stuff then.

Processing has been a run of ABE, colour calibration, histogram stretch and 30s of playing with curves.
All in all, very happy with the lens! By tomorrow I hope to have flats, darks, bias and ~8 hours of exposure.