Background

This was a really tricky target for a number of reasons. First, the nebula is only visible during a narrow window of opportunity from my garden, as it passes my house’s chimney but before it reaches the shed roof. That’s a few hours at most per night. Also, the weather was awful and I was clouded out almost all the time. Then worst of all, my camera fan broke! I had to order a new fan and then install it before I could continue. All in all, a bit of a disastrous six weeks.

Despite that, I managed to build up just over 11 hours using my Optolong L-Ultimate. I then collected almost two hours of RGB data (by simply removing the filter). My plan was to use this RGB data just for the stars. However, I found that despite the short integration time, M43 — the smaller nebula to the right of the image — showed up well. This is probably due to the fact that it’s part reflection nebula, so shows up better in broadband wavelengths compared to the larger hydrogen-rich M42 nebula that dominates the picture. So, I followed a simple tutorial and combined my L-Ultimate and RGB data into a single image. I was happy with how well that turned out.

As for the stars, I just couldn’t get them looking as good in RGB as the L-Ultimate data. I even tried shooting shorter subframes for RGB — 30 seconds, instead of my standard 120 — but it didn’t seem to make any noticeable difference overall. So, the stars are actually from the L-Ultimate data. There wasn’t much colour in the RGB version, so no big loss there.