The Rosette Nebula is a very special object to me. It has been almost exactly five years since I last photographed it – back in February and March 2021, when I was just taking my very first steps in astrophotography. It was my first “project” that stretched across two nights. Now, five years later, I set out to capture the Rosette Nebula once again. This second attempt turned out to be far more chaotic than expected.
The new imaging series began in January, though under anything but ideal conditions. Hardly a single evening offered truly good weather: clouds, humidity, high fog, and repeatedly only partial nights set the rhythm. On January 21, I initially captured the first red and green exposures, about 20 subframes each at three minutes. The blue channel followed a day or two later – but was completely discarded because something was fundamentally wrong. In addition, I discovered that I had centered the wrong object: instead of the Rosette Nebula, NGC 2238 was in focus, pushing the actual nebula awkwardly toward the edge of the frame.
The first integration of these data confirmed the impression: the quality was simply unusable. The Rosette Nebula sits relatively low in the sky, moves unfavorably across my field of view, and is further affected by a streetlamp behind my house. Although I shield it with a kind of folding screen, in this configuration the camera repeatedly came very close to the frame of that shield. The result was unwanted spikes and artifacts – present in virtually all exposures.
So I decided to start over once more and invest additional nights. This time I centered on Sharpless 275. On January 24, I re-captured the blue channel, collecting 21 subframes at 180 seconds each. The same evening I also recorded the red channel again, though time allowed only ten frames. Early processing showed that the green channel from the earlier nights was actually the best – but even here, strange, uneven structures appeared around bright stars.
After another waiting period, I finally managed to capture additional targeted green data on February 7: 14 subframes at 300 seconds each. Only afterward did I realize that different exposure lengths were now mixed together, but in the end everything could be combined effectively. Altogether, nearly two and a half hours of total integration time went into the final image.
Despite all the challenges – not a single night went completely without issues – I am very satisfied with the result. What fascinates me most is the direct comparison with the image from five years ago. In that time, everything has changed: my experience, the telescope, the camera, and above all my understanding of acquisition planning and image integration. The difference between then and now truly feels like night and day.
High-resolution on Astrobin:
The annotated image:
Session Details:
| Telescope | Baader Apo 95 Travel Companion |
| Focal Length | 590mm |
| Erecting Lense | Baader M68 Field Flattener |
| Camera | ToupTek SkyEye62AM |
| Filter | Baader LRGB CMOS Optimized 50.4mm |
| Mount | Skywatcher HEQ5 Pro, Belt and Hypertuned |
| Guiding Equipment | William Optics Uniguide 50 |
| Guiding Camera | ToupTek GPM462M |
| Photography Date | January and February 2026 |
| Exposure-Time Lights | R 10x180s G 15x300s B 20x180s |
| Correction frames | FLATS, DARKS |
| Sensitivity | GAIN 100, Offset 125 |
| Processing Date | 02/08/2026 |
| Software Stack | Stellarmate OS, PixInsight |
| Capture Place | Koblenz, Germany |
