MasterFlatHa

Ha master flat frame - un-stretched - this was taken with the original filter orientation - the radial interference pattern is even visible in the un-stretched version that was seen more clearly in the stretched frame

40 flat frames at 10.79 seconds using Sequence Generator Pro. Integration time was determined using SGP flats calibration wizard.
Illumination was using an Alnitak Flatman with two layers of tee shirt fabric.
No bias frames used only Flat Dark Frames - 40 flat dark frames
ORION EON 115mm APO
ZWO ASI1600MM-COOL with a Williams Optics Flattener IV at F/5.75 with Gain - 75, Offset - 40, USB - 60, Temp = -15C