The region of Cepheus, near the border with the Constellation Cygnus is very complex. The plane of the Milky Way galaxy is off the left edge of the image. Reddish-brown interstellar dust is seen throughout the image. The large pink nebula in the left half of the image is the Elephant Trunk Nebula (IC 1396). The pink color is emission from Hydrogen (H-alpha in the red, and H-beta plus H-gamma in the blue). In the right half of the image is SH2-129, a faint hydrogen emission nebula. In the center of SH2-129 is a bright blue star, and extending in the 2 to 8 o'clock direction is a lighter zone which is Oxygen Emission from the faint Ou4 nebula. Going through the middle of the image, top to bottom is a zone of blue stars, hot, relatively young stars. At the left edge, below center is the spiral galaxy, NGC 6946.The OU4 nebula is difficult to discern because the natural color image recorded too many stars. I did an aggressive star reduction procedure, but the star density is still overwhelming to see faint nebulae. Along the strands of OU4 are many stars, which are not apparent in many online images made of the area with narrow band filters. The lesson here is the nebulae needs to be imaged with longer focal lengths, like 300 mm when imaging in RGB color to provide better separation of the nebulae and the many stars.
Post processing: raw conversion with Photoshop ACR and stacking with deep sky stacker. Stretched with rnc-color-stretch, and final adjustments in photoshop. No darks, no flats, no bias frames (flat field is in the ACR lens profile and corrected during raw conversion, bias is in the EXIF data). The exposures were tracked on a Fornax Lightrack II with no guiding. This is the full frame image after cropping edges from stacking.
More info at:
https://clarkvision.com/galleries/gallery.astrophoto-1/web/squid+elephant-trunk-rnclark-105mm-2022-av190-IMG_3521-641-i2-2173sw.htmlThe is a well calibrated image. For more info see: Sensor Calibration and Color
https://clarkvision.com/articles/sensor-calibration-and-color/
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