Sadr Region Wide Field

I ended up imaging a similar region twice in 2025. My first effort was a test shot using equipment destined for a remote observatory. That data turned out so well that it deserved its own page.

This is a wider field of the region around Sadr, or Gamma Cygni, which is the brightest star in this image.

One distinctive difference between the two cross-shaped constellations is that there is a bright star that marks the “heart” of the northern cross. This star is Sadr, or Gamma Cygni, which is the brightest star in this image.

While the emission nebula around Sadr is designated as IC 1318, it is also listed as SH2-108, which is entry 108 in the Sharpless Catalog of HII regions.

Data for this image was gathered over multiple nights in August 31 and September, 2025. The camera used was a one-shot-color (OSC) camera instead of the usual mono camera using special narrowband filters that helped reduce the effects of light pollution. Specifically, I used an Antlia-brand Alp-T filter designed for color cameras that passed H-alpha and OIII data. I also used an Antlia-brand RGB Tri-band filter that is designed to cut light pollution while passing regular RGB color data for color cameras.

With the type of data gathered, my original plan was to create an Ha/RGB composite as well as an Ha/O3 image. In the course of processing my data, I made a lucky mistake at one point while processing the Ha/O3 component which resulted in a pleasing pseudo-SHO-like image. I decided to showcase all versions here. From left to right, the thumbnails represent Ha/RGB, Ha/O3 and a pseudo-SHO image using just Ha/O3 data. Stars from the RGB dataset were used in all three depictions.