This mosaic was created spontaneously. I wanted to shoot the area around NGC6888, WR134 and SH2-101 in order to make 3 different pictures in bicolor scheme. However at the end I don't have enough O3 frames to do this. As a result, during processing, I noticed that all three images have enough common FOV to make a three-panel mosaic. The mosaic below spans the region between the stars γ and η Cygnus, at the very heart of this summer constellation. The narrow-band image shows well-known nebulae such as NGC6888 (Crescent), SH2-101 (Tulip) and SH2-104, and many other faint stuff at the background.
Image on Astrobin (Cygnus core mosaic)
Starless image on Astrobin (Cygnus core mosaic)
The Crescent Nebula (also known as NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures.
The Tulip Nebula (Sharpless 101) is an emission nebula located in Cygnus constellation. It lies at an approximate distance of 6,000 light years from Earth and has a linear diameter of about 70 light years. The HII region is called the Tulip Nebula because its shape resembles the form of a tulip.
The emission from the Tulip Nebula is powered by ultraviolet radiation of the hot young star HD 227018. The O6.5III class star belongs to the Cygnus OB3 association and has a visual magnitude of 9.02. In images, it can be seen near the nebula’s center.
Sh2-104, also cataloged as DWB 14, is about 14,000 light years away toward the Cygnus constellation. This is located due east of the popular Crescent Nebula. Sh-104 is viewed by professional astronomers as a good illustration of the "collect and collapse" model of star formation triggered by the rapid expansion of a HII.
Own remote observatory, 50 km from Kiev, Bortle 4 zone. Imaged during May - August 2020. AZ-EQ6 mount, Jupiter-37A lens (135mm at 1/3.5), QHY22. Guide - 50x9 finder with DIY Cam10 camera.
Astrodon 5nm Ha: 224 x 900s (total for mosaic)
Total exposure - 61 hr.
Captured in SGP, processed in Pixinsight.