A supernova occurred in the Pinwheel Galaxy during this imaging project. It was discovered during daytime hours from my observing location in the UK, but as soon as the skies were dark, my telescope was back on the target collecting more light. This meant I was able to make a before / after comparison. I can’t claim any credit for being particularly organised; it’s just a happy coincidence that I was imaging this target every clear night around the time the supernova was detected.

The weather forecast then predicted an unusually long period of clear skies. This presented me with a dilemma: I had already gathered nearly 20 hours of data, which is what I’d initially planned. But if I kept going, would I be able to detect any noticeable change in brightness of the supernova? I decided it would be fun to try, so I just kept going every clear night for the next few weeks.

Ultimately I couldn’t really see an interesting enough change in brightness night on night, but before I knew it I was approaching 70 hours of RGB data — by far the most for any of my astro targets.

I then got thinking about my previous galaxy shoot, M81 and M82. That turned out well, but I regretted not getting any Hα data to show glowing red areas of star formation. I shoot using an OSC camera and don’t have a dedicated Hα filter, but I do have an Optolong L-Ultimate, which captures Hα and OIII. So, I gathered 30 more hours of data using this filter, then extracted the Hα data (i.e. the red channel), and combined this with the 70 hours of RGB. Hey presto, a nice round 100 hours of data, resulting in an HαRGB image.

This slider comparison shows the RGB data (left) with what it looked like after I added in Hα.

Finally just for fun, this slider comparison shows my image compared to the same galaxy imaged by the Hubble Space Telescope. (To be fair, the Hubble data absolutely trashes mine when viewed at full resolution!)