The California Nebula (NGC 1499) is an emission nebula located in the constellation Perseus.  Named after the nebula’s resemblance to the US State of California, it is extremely large. 

Even though its total integrated magnitude is that of a bright, 5th magnitude star, this light is spread over an 2.5° (60 light-years across) and so it has a very low surface brightness.  Therefore this nebula is extremely faint and very difficult to observe visually but the beautiful structure can be observed dramatically through astrophotography. 

It lies at a distance of around 1,500 light years from Earth.  The distinct red glow is caused by the nearby hot, blue-white star Xi Persei that can be seen in the top right of my image.  The energetic, O-type star (also known as Menkib) is a blue giant is over 12,000 times brighter than our own sun.  This massive star ionises hydrogen atoms and in particular the fluorescence is due to the excitation of the hydrogen-beta line in the nebula. 

This image is from 5 nights worth of data from the 25th February to the 8th March with less than ideal conditions over a full moon.  The unfortunate trend continues in the UK of having clear nights exclusively during a bright moon. Despite this the Radian Triad Ultra filter managed successfully isolate the hydrogen spectra from this target and combined with some new processing tricks we have a dramatic final result.  The position of Perseus in the night sky means this project finished for now but it is definitely something I will revisit in the future.

Hope you enjoy it.

Total Integration - 18 Hours 25 Minutes

ZWO ASI183MC Pro

William Optics RedCat51

iOptron CEM40

ZWO ASI120MM-Mini Guide Camera and ZWO Mini Guide Scope

Radian Triad Ultra Quadband OSC Filter

Images captured in my Bortle 4 skies in Shropshire with ZWO ASIAir Pro.  Processed with PixInsight, Photoshop and Topaz DeNoise AI.

Follow @leather_ben on Instagram to learn more and if you have any questions about astrophotography or my images, don’t be afraid to message me!