The Orion Nebula, M42 and M43, with surrounding associated nebula and star clusters, such as the Running Man Nebula above (NGC 1975) and blue star cluster above it, NGC 1981. This is one of the most often photographed but most challenging dee-sky objects to shoot, because of its huge range in brightess from the bright core to the outlying wisps of dim red nebulosity. Capturing it all in one frame requires a form of “high-dynamic-range” techniques: shooting several different exposures and manually stacking and masking them in Photoshop. I shot and processed this image for use as a demonstration and tutorial image for my Photoshop for Astronomy Workshops. This demonstrates the methods and result of masking several different exposures to retain details in the bright core while also bringing out the faintest outlying bits of nebulosity, compressing the dynamic range tremendously. All processing was done with Adobe Camera Raw and Photoshop CC 2014. Total processing time from Raw to final was about 3 hours. The image is made of: - 10 x 6 minute exposures, Median combined in a registered stack, at ISO 1250. The median stacking reduced, but did not completely eliminate, the satellite trails from geosatatonary satellites that were in almost every frame. - 5 x 1.5 minute exposures at ISO 1250 for the mid-level brightness areas, blended using Darken mode - 5 x 30 second exposures at ISO 800 for the bright core, blended using Darken mode - 5 x 30 second exposures at ISO 400 for the brightest part of the central core around the Trapezium stars, blended using Darken mode Shorter exposure layers were stacked and masked using a luminance mask: created by Command Clicking on the RGB Channel to select just the highlights of that exposure then using that selection to create a mask to reveal the core area and hide the rest. Additional top-level layers were added for enhancing detail overall: - Luminosity layer created from the Red channel, and blended using Luninosity blend mode - Sharpening layer created from a “stamped” merge of all layers and with a High Pass filter applied, and blended using Overlay blend mode. All adjustments and filters were applied through adjustment latyers and smart filters so every aspect of the image could be re-tweaked at will later. Masks were blurred using Feathering in the Mask Properties panel. No destructive filtering to images or masks was employed. All frames were taken with a filter-modified Canon 5D MkII and through a TMB 92mm apo refractor at f/5.5 with a Hotech field flattener. Diffraction spikes on stars added with Noel Carboni’s Astronomy Tools actions. Final noise reduction and debanding applied using Nik Collection DFine. Taken from Silver City, New Mexico, January 22, 2015.
Comet Lovejoy, C/2014 Q2 amid the clusters, nebulas and dark dust clouds of Taurus and Perseus, on Friday, January 16, 2016. Its long blue ion tail stretches back at least 15°, almost to the open cluster NGC 1647 on Taurus at the left edge. At centre is the Pleiades star cluster, M45; at top right is the red California Nebula, NGC 1499, in Perseus, while the field is filled with the dark dusty lanes of the Taurus Dark Clouds. At left is the red giant star Aldebaran amid the V-shaped Hyades star cluster. I turned the field 90° clockwise from the original orientation, putting the “bottom” of the field (the area farthest south and closest to the horizon) at the left edge. North is to the right here. This perhaps provides a “more natural” orientation to the comet for most people. This is a stack of 10 x 2 minute exposures with the Sigma 50mm lens at f/2.5 and filter-modified Canon 5D MkII at ISO 1600. Tracked on the Sky-Watcher Star Adventurer, but not guided. Shot from City of Rocks State Park, New Mexico, Jan 16, 2015.
Star trails showing Orion and Taurus rising behind the rock formations of City of Rocks State Park, New Mexico. I shot this Monday, Dec 29, 2014. The colours of the stars and trails have been boosted in vibrancy to show the colour differences better. Red Betelgeuse is at left, while the pinkish Orion Nebula is at centre. The cyan trail at right is Comet Lovejoy (C/2014 Q2). Light from the waxing quarter Moon illuminates the foreground. A satellite streak is at right of centre. This is a stack of 260 exposures, each 30 seconds at f/2/8 with the 24mm lens and Canon 6D at ISO 400. The foreground is mostly from one frame, the first frame, to preserve shadows. I also added larger star glows around the brighter stars of Orion to make the constellation patern more obvious. It starts just above the rocks at lower left and rises to above centre. The images were stacked with the Advanced Stacker Actions from Star Circle Academy, using the Elastic Stars effect to add point-like stars from the first and last frames.
