Celestial hemisphere:  Northern  ·  Constellation: Cygnus (Cyg)  ·  Contains:  22 Cyg  ·  27 b01 Cyg  ·  28 b02 Cyg  ·  29 b03 Cyg  ·  34 P Cyg  ·  36 Cyg  ·  37 gam Cyg  ·  40 Cyg  ·  B145  ·  B342  ·  B343  ·  B344  ·  B347  ·  Crescent Nebula  ·  HD188591  ·  HD189301  ·  HD189432  ·  HD189492  ·  HD189574  ·  HD189942  ·  HD189959  ·  HD190131  ·  HD190275  ·  HD190359  ·  HD190381  ·  HD190402  ·  HD190428  ·  HD190446  ·  HD190466  ·  HD190467  ·  And 390 more.
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Sadr Region, 135mm lens with ASI294MC, Josh Loum
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Sadr Region, 135mm lens with ASI294MC

Getting plate-solving status, please wait...
Sadr Region, 135mm lens with ASI294MC, Josh Loum
Powered byPixInsight

Sadr Region, 135mm lens with ASI294MC

Equipment

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Acquisition details

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Description

Wide field of the region around Sadr (γ Cygni), with a 135mm f/2 Samyang lens and ASI294MC color cooled CMOS camera.

This was an experiment with a huge number of short exposures (1991 x 5 sec), to see how high gain / low read noise / fast optics would work. At 5 second exposures no guiding was needed.

The initial calibration and integration took multiple hours total, even on an AMD 3950X with 128GB RAM. I also drizzled so that the ultimately-downsampled image would be slightly sharper, which added more processing time but I feel like it was worth it.

Processing was PixInsight for calibration, stacking, and initial curves, then a 16-bit TIFF to Photoshop CC for numerous curves layers.

With my light pollution, and also probably because I started it too low in the sky, there were decent gradients that took some Photoshop work to clean up. Not too hard though, using curves layers with gradient masks.

This is also the first time I've used this lens for astro. There's a bit of tilt - you can see it in the star shapes, and also in the chromatic aberration (with an unbranded UV/IR filter) which is blue near the bottom and green near the top. Some of it was cleaned up in Photoshop, but I couldn't get it all. Horizontally roughly through the center of the image, the star shapes are great even wide open - this is an amazing lens, just need everything truly square at f/2!

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Sadr Region, 135mm lens with ASI294MC, Josh Loum