The California Nebula


“This was, also, the last image I took with my modified Canon 450D”

The California Nebula is a region of gas in space that resembles the state of California in America. A large billowing region, you’ll need a large field of view if you hope to fit the entire nebula within one frame. Since I didn’t have that field of view, I decided to focus my framing on a specific region.

I originally shot this to work alongside Trevor at AstroBackyard‘s HaRGB composite tutorial. I ended up however making a large project out of it that incorportaes over 18 hours of total integration time between Hydrogen Alpha and RGB data. Despite it not being entirely suitable for narrowband, I shot this with a Canon 450D.

Framing Considerations

As previously mentioned the California Nebula is large. However it would just about fit into my Skywatcher Evostar 80ED’s field of view (with a 0.8x reducer and a crop body DSLR). Even though it fit, I wanted a more dramatic picture that looked balanced and obeyed the rule of thirds. So I decided to frame it with the bright star Menkib in the top right of the frame. I chose this framing as it would allow me to put the nebula on the left 1/3 of the frame at its angle, and balance the image out using Menkib.

Framing Considerations Of California Nebula
How I Framed My RGB Image (note the amp glow). Quick Edit.












I mainly wanted to do this to add some drama to the image. I believe it’s quite a pleasant looking target already but I like how I chose to frame it at least.

Finding NGC 1499

Sometimes trying to find a target in your DSLR’s live view is practically impossible. DSLRs lack the sensitivity at times to show up deep sky objects in short loops. One advantage then of having Menkib where it is meant I could use that bright star for framing and focusing. That is, with the Skytech CLS-CCD light pollution filter in the camera.

When I swapped it for the Baader 7nm Hydrogen Alpha filter I could all but kiss goodbye to being able to see anything in the live loop.

What My Guide Loop Shown For Manual Solving

It was so dim I ended up using my guide scope’s feed to manually plate solve my target. I don’t have the image anymore but this is sort of what I would see in my PHD2 loop, and that’s how I chose to frame when I was using the narrowband.

It wasn’t easy, but I felt it was an adequate work around.

Target Details

  • RA / Dec: 04h 03m 18s / +36° 25′ 18″
  • Constellation: Perseus
  • Apparent Magnitude: +6
  • Distance: 1000 Light Years
  • Type: Emission Nebula

The California Nebula in Hα

The main reason to add Hydrogen Alpha narrowband data to emission nebulae is added contrast. Blending the Ha into RGB data makes the aforementioned HaRGB composite image and really makes the picture POP. It’s well worth adding. Just look at the difference between broadband and Ha. There is a tonne more contrast in the Hydrogen Alpha, as it rejects any wavelength that doesn’t fall into its bandpass. Even Menkib has been reduced – another effect of adding narrowband data.

Demonstrating The Difference Between Ha and Broadband Data On The California Nebula








You can see the RGB data has some detail there, but when you add in the high contrast of the Ha, it makes sense. It wasn’t easy, I had to use very long exposures and there’s a lot of amp glow in my subs; but the end result was worth it.

The Red Channel and Ha Channel of the Cali Neb
Contrast difference from Red channel (left) to Ha data

My First Long Project

What was meant to just be an experiment in adding a new skill to my processing abilities turned out to be an epic journey of soaking up the data. 7 hours became 10 which became 20. I weighed it more towards the Ha data than the RGB. Had I done this again I would probably balance it out a lot more. This was, also, the last image I took with my modified Canon 450D. I progressed on to a dedicated astronomy camera after that.

NGC 1499 shares a special place in my heart; it was my first long project, it was my first HaRGB composite image and I just enjoy the look of the target in general. Menkib burning brightly and illuminating this enormous gas cloud light years away from us and light years long. The numbers are difficult to comprehend but one thing is for sure. I have a picture I will treasure for the rest of my life.

Will I return? Yes, I will. But for now I enjoy what I have, and I hope you do too.



  • Skywatcher Evostar Pro 80ED
  • Skywatcher HEQ5
  • Canon 450D (full spectrum modified)
  • Baader 7nm Ha 2″ Filter
  • Skytech CLS-CCD Clip-In Filter
  • Altair Starwave 50mm Guidescope
  • ToupTek ToupCam Guide Camera