Moravian instruments, Inc., source: https://www.gxccd.com/art?id=567&lang=409, printed: 15.12.2019 2:53:13
|NGC 7023 “Iris” nebula in Cepheus is a popular target for astro-photographers. Its blue-green color is caused by reflection of a light from a 7th magnitude star in its center. But the nebula itself is much greater than the shining part around the bright star, only the majority of its gaseous clouds remains hidden in shadows.|
However, long enough exposure can accumulate scattered light of remote stars in our Galaxy and reveal also dark parts of the nebula.
Miniello Massimo Stefania used his G3-11000 camera on the Takahashi FSQ106 refractor to combine 5 hours of exposures through red, green and blue filters with another 5 hours of unfiltered exposures to capture this beautiful image of Iris.