NGC 6888, AKA the Crescent Nebula, is a popular target for astrophotographers in the constellation Cygnus — it’s about 12 x 18 arcminutes in size, and located about 2 degrees southwest of Sadr (the center of the Northern Cross). NGC 6888 is probably about 5000 light years distant, and formed by the stellar winds associated with Wolf-Rayet star WR 136. As an emission nebula, it is easily captured by a hydrogen alpha or OIII filter.
Data was acquired at MYHY Observatory in the Philadelphia suburbs. 28 hours of hydrogen alpha and 6 hours of RGB data with an OGS 10″ RC (from 2007) was combined with 18 hours of OIII data with a Takahashi FCT-150 (from 2018). All photons were captured using the SBIG STL 11K on a Paramount ME. Data reduction was in Maxim, star alignment in Registar, and subframe integration in PixInsight. RGB combine/ABE and curves were in PixInsight; all other Ha/OIII processing was in Photoshop. The image was assembled as a bicolor, using Ha=Red/OIII=Green/OIII=Blue, after which time the RGB stars were added.