Another image captured at Oregon Star Party this year, framing both the Iris and Ghost nebulas in Cepheus. This is a challenging target, covering large areas of low-contrast reflection nebulosity, and which benefits from the extremely dark and transparent skies available at OSP. This is a redo of an attempt to capture the same framing at last year’s OSP that was foiled by smoke. I kept my notes from that previous run, and was able to use the same reference points.

The Ghost Nebula is a reflection nebula composed of inert dust illuminated by nearby stars and designated variously as Sharpless 136, IC63 and van den Bergh 141.

The nearby Iris Nebula, NGC7023, is another reflection nebula, but displaying the spectacular blue scattered light from the bright star SAO 19158. The light we see is blue due to the preferential scattering of shorter wavelength light; this is typical for reflection nebulae.

Both of these images are close-crops from the full frame image shown here:

You can see a substantial amount of dust to the left of the image, and the scattering effect results in a blue haze around any bright stars.

This was captured using a mono SBIG STL-11000M fitted with Astrodon Gen 2 Series-I LRGB filters and cooled to -10 ° C, through a Takahashi FSQ-106EDXIII and mounted on an Astro-Physics Mach 1 GTO. All control and capture using TheSkyX Pro, and all processing using PixInsight.

Total exposure time for this image was 6 1/2 hours, with 5 hours dedicated to luminance, and 1/2 hour each for red, green and blue. The original data set that I used had only 2 1/2 hours of luminance, captured Thursday night (August 1st – 2nd), but I was able to capture an additional 2 1/2 hours on Friday night to add to it.

I also wrote up a brief explanation of the processing steps that I used here. The explanation includes images combined using the first night’s data, and does not include the full 5 hours of luminance.