Sh2-140 is an H II region and a star-forming nebula located in the constellation Cepheus, about 3,000 light-years away from Earth. It is part of a larger molecular cloud complex known as LDN 1204. Sh2-140 is characterized by its bright emission nebula, where new stars are forming from collapsing clouds of gas and dust. The region contains several young stellar objects, including protostars and massive young stars that emit intense ultraviolet radiation, ionizing the surrounding gas and causing it to glow. This star formation activity is driving the expansion of the H II region, which is a key site for studying the early stages of star development and the processes that trigger and regulate star formation in molecular clouds.

The weather forecast predicted several cloudless nights at the end of August and the beginning of September, which also coincided favorably with the moon phase, so I decided to take this opportunity to capture Sh2-140 in the constellation Cepheus. I had seen images showing faint gas and dust clouds surrounding the nebula, and I wanted to make these visible using the RASA at f/2.2, focusing primarily on the RGB data. In the end, I accumulated nearly 25.5 hours of exposure time, with about 20.5 hours dedicated to RGB and 5 hours to H-alpha. The images were taken from my backyard on the outskirts of the city under Bortle 5 conditions.

The processing was more challenging than expected because, despite the long exposure time, everything was still quite faint overall. I blended the H-alpha data very subtly to keep the RGB look. I was very pleased that the dust clouds became visible in the lower right of the image, as well as the two reflection nebulae VdB 153 (bottom center) and GN 22 12.3 (top center). Sh2-140 also stood out nicely with its shockwave, along with the gas cloud Sh2-145 (left).