The California Nebula is an emission nebula located in the constellation Perseus. The name comes frome its resemblance to the outline of the US State of California.
It was discovered in 1884 by E. Barnard.
The blue star next to it is Menkib, a blue giant, over 12.000 times brighter than our sun. This star ionizes the hydrogen atoms in the California Nebula and is responsible for the creation of this nebula.
This is the gear I used:
Red cat 51
Skywatcher EQ3 sync
ZWO 183 GT MM (-5°, bin × 1, gain 130)
ZWO 120 MM mini (guide camera)
ZWO 30 mm (guide scope)
ZWO ASI AIR PRO
Baader HA 3.5 nm filter ( 84 × 300sec)
Baader OIII 8.5 nm filter (51 × 300sec)
Calibrated with darks and flats.
Bortle 9 sky
Taken with the ASI AIR PRO, stacked in DSS and processed in PixInsight & Photoshop.