Latest Image: M42 HDR from SRO

Steve Reilly

What makes this a HDR image is the use of multiple exposure times. The luminance data was taken using 120 seconds, 300 seconds, and 600 second exposures. The RGB data is 300 and 600 second exposures only because I forgot to setup the 120 second series but decided later it wasn’t needed. The total data used is 114,240 seconds which equals 1904 minutes which = 31.73333 hours. The breakdown is 15.73 hours luminance and 16 hours RGB. At the smaller scales it looks maybe overcooked but at the larger you see the fine details and gas that’s somewhat lost in the smaller images. It pays to looks t these on a larger monitor vs say a cell phone. There’s probably 8 hours of processing time which includes calibrating, aligning, and combining the 247 luminance images and 96 RGB images. The images combined to make their respective masters and in the RGB case, the RGB 300 and 600 second RGB combined images into one using Pix Insight’s High Dynamic Range combine process. Actually all of the processing is done in PI. Same with the luminance, each timed group made into their respective masters and then combined as a HDR image. Each HDR image is cropped to clean the edges up from the dithered guiding process and then stretched, the background cleaned up using Dynamic Background Extraction, and the fine details enhanced by use of HDR Multiscale Transformation. That process brings out various details such as galaxy cores and finer details in nebula depending on the masks used and the number of layers.


SRO Image Page or Direct Link


Thanks for Looking,



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