SH2-155 or Cave Nebula is a diffuse nebula in the constellation Cepheus. It is called a diffuse nebula because it is located withing a larger nebula complex containing emission, reflection, and dark nebulosity. The nebula is in an ionized H II region with ongoing star formation activity, at an estimated distance of 2 400 light-years from Earth.

Data for this image was gathered 2024-09-19, 2024-09-21, 2024-09-26, 2024-09-28, 2024-09-30, 2024-10-01, 2024-10-03 and 2024-10-11.
Data for this image: 60x300s S-II, 67x300s Ha, 66x300s O-III.
Total number of exposures 193 with a total integration time of 16 hours.
Processing: PixInsight with SHO palette with SHO stars.
Equipment: SkyWatcher EvoStar 80ED Pro (0,85x FR/FF) and ZWO ASI294MM Pro on SkyWatcher HEQ5 Pro with SkyWatcher EvoGuide 50ED and ZWO ASI120MM Mini. ZWO SII, Ha, and OIII filters.
Location: 63 degrees north with a bortle 4 sky.