Collecting Photons

Crab Nebula

A night of poor transparency but of excellent seeing. Autoguiding error was under 1" and everything worked out flawlessly. Celestron 8, f6.3, modified Canon 350D, 17x8' at iso 800. Preprocessing in Iris (offset, dark, flat and white balance). Pre-processing was completed with ten iterations of R-L deconvolution (RL2 in Iris).

Processing was a long affaire. Hyperbolic asinh stretching for best colour discrimination in the nebula and stars. DDP for the dimmer parts of the nebula. The two layers were blended together in Photoshop CS and at this stage also levels and curves were applied. The red layer was processed in PixInsight to extract more details from the red filament by applying wavelet filtering. The RGB composition was treated with a very moderate erosion operator and completed in Photoshop.

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Send anything that comes to mind to Gimmi Ratto gimmi@in.cnr.it