More Stretch Acadamy Images

I've been practicing the lessons I've taken from Adam Block's Stretch Academy. These include:

Images with very high dynamic range areas with interesting detail are best initially stretched with a tool like the iterative masked stretch from Herbert Walter at skypixels.at. Otherwise a midtones transfer function stretch like the Pixinsight STF/Histogram Transformation is a good start.
Stars and nebulosity almost always should be stretched seperately. A stretch that brings out dim nebulosity detail will saturate bright stars causing them to loose all of their color. Stetching, which makes image data permanently non-linear, should be done after deconvolution and perhaps some initial noise reduction.
Stretching can be controlled in localize regions of brightness to bring out nebulosity details. An easy way to do this in PixInsight is with the Generalized Hyperbolic Stretch tool from Mike Cranfield at ghsastro.co.uk.

Adam Blocks videos not only introduced me to some new tools needed for this workflow, but made me give some thought to the big picture of what I do in processing deep space images. I've felt that I had a much better handle on processing planetary images, with too much trial and error for DSO images. Now I feel much more confident with DSOs. Nothing cements and refines new skills like practice. I was amazed at the improvement in these. They all are below. Details and full size images are linked.

Marfa Western Veil Nebula
The Western Veil Nebula (NGC 6960) with the Witch's Broom adjacent to 52 Cygni at the bottom. These filamentary nebula are remnants of a super nova explosion from over 5000 years ago. The Veil nebula is about 2600 light years distant. The dark skies of Marfa allow true color broadband imaging. I used a William Optics Redcat 250/51mm f/4.9 Petzval refracting telescope, Baader UV/IR cut filter, and ZWO ASI533 MC Pro cooled camera on a Sky-Watcher AZ EQ5 Pro mount. Imaging was controlled with a ZWO ASIAIR Pro astrophotography controller.Image data taken 2021-06-11 from 07:30 to 10:30 UT with 3 hours of total exposure. 59 of 67 3 minute exposure images were calibrated with a master dark, drizzel stacked, and processed in Pixinsight, with RC-Astro Noise/Blur/StarXTerminator plugins. Final exposure and crop in PS.

North America & Pelican Nebulae
Reprocessed North America (NGC7000) and Penguin Nebulae (IC5070) in a HOO palette from a dual bandpass narrowband filter. Taken last fall with Cygnus high in the late-summer sky from Joppa, Texas, taken 2021-09-05 06:30 UT. WO RedCat 250/51mm telescope, Optolong L-eNhance NB Filter, ZWO ASI533 MC Pro cooled camera at -5C, SW AZ-EQ5 Pro mount, ZWO ASIAIR controller. 42 3min images drizzle stacked . Processed in a HOO palate in PixInsight with RC-Astro Noise/Blur/StarXTerminator and GHS plugins. Final exposure and crop in PS.

Antares Pentagon
The Antares Pentagon is bounded by Antares, M4, Al Niyat, IC4603, and IC4605 (i Sco). In addition to some of the most colorful nebulosity in the Milky Way, the Rho Ophiuchi cloud complex, it includes bright, dark, and emission nebulae as well as open and closed star clusters. This nebulasity forward processing of 102' of 3' exposure data taken starting 2022-04-26 05:17 UT from Fort Davis, Texas. William Optics RedCat 250/51mm telescope, Baader UV/IR cut filter, ZWO ASI 533 MC camera, and SkyWatcher AZ-EQ5 mount, ASI EAF and guide camera. All were controlled with a ZWO ASIAir Plus Controller. Processed in PixInsight, StarXterminator, NoiseXterminator, and Photoshop.

Elephant Trunk Nebula with the Garnet Star
The Elephant Trunk and the Garnet star in a NB HOO palate. Taken from Austin Texas, WO RedCat 250/51mm telescope, Optolong L-eNhance NB Filter, ZWO ASI533 MC Pro cooled camera at -5C, SW AZ-EQ5 Pro mount, ZWO ASIAIR controller. hree hours of exposure 62 3' lights. Processed in a HOO palate in PixInsight, StarXTerminator Topaz DeNoise AI, and Photoshop.

Lagoon & Trifid Nebulae
The Trifid, Lagoon, and dimmer but lovely IC 4685, are a highlight of southern summer skies. This image is from from the Texas Star Party in Fort Davis. Imaged starting 2022-04-30 08:31 UT. I stacked and processed 15 five minute expsoures taken with a William Optics RedCat 250/51mm telescope, Baader UV/IR cut filter, ZWO ASI 533 MC camera, and SkyWatcher AZ-EQ5 mount, ASI EAF and guide camera. All were controlled with a ZWO ASIAir Plus Controller. I've rerendered as a drizzle stack in PixInsight with the the BlurXTerminator, NoiseXTerminator, and StarXTerminator plugins in Pixinsight and final exposure adjustment in Photoshop.

Arizona Andromeda
M31 under the dark skies of the Coconino Plateau in northern Arizona. Seventy minutes of 30" exposures of Andromeda on 2020-09-14. William Optics RedCat 250/51mm Petzval refractor and ZWO ASI533MC cooled astrophotography camera. Controlled by a ZWO ASIAir Pro. All on a single axis Vixen Polarie mount. Reprocessed 12/2022 with the BlurXTerminator, NoiseXTerminator, and StarXTerminator plugins in Pixinsight with drizzle stacking and final exposure adjustment in Photoshop.

Content created: 2023-06-14

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