During the summer months of June through August 2025, I dedicated myself to one of my most ambitious astrophotography projects so far: capturing Sharpless 119, also known as the Clamshell Nebula, in the constellation Cygnus. This extensive emission nebula lies approximately 2200 light-years away and spans several degrees across the sky.
The Imaging Sessions
The total exposure time for this project amounted to an impressive 41 hours, spread over 14 nights. After discarding frames affected by clouds, wind, or guiding issues, the net exposure time totaled 32 hours. These images were captured using my Baader Travel Companion 95 telescope mounted on an HEQ5 Pro, with a ToupTek SkyEye 62M mono camera. I used Baader 50 mm filters in Luminance, Red, Green, and Blue.
The sessions were spread over June to August, with a short break during my summer vacation. Notably, session 14 saw another use of the Red filter to emphasize the hydrogen and sulfur emission regions. This decision came after test processing revealed that the Red channel could be stretched particularly effectively.
Unfortunately, sessions 11 and 12 had centering issues, so their images were excluded from the final result. These were also the shortest sessions, and the guiding and seeing conditions were suboptimal, so the loss was manageable.
High-resolution on Astrobin:
The annotated image:
Technical Setup
A few months ago, I switched my optical chain entirely to Baader components to reduce internal reflections. A key step was replacing the Off-Axis Guider with a William-Optics Uniguide 50 mm guide scope and a ToupTek 462 mono camera. This change significantly improved both image quality and guiding performance.
The HEQ5 Pro mount consistently achieved guiding accuracy under one arcsecond. Longer guiding segments ran around 0.5 arcseconds, with typical variations between 0.6 and 0.8 arcseconds. This precision was crucial to capture the fine details of the nebula complex.
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 | June 25 – August 25 |
| Exposure-Time Lights | R 115x300s G 45x300s B 35x300s L 305x300s |
| Correction frames | FLATS, DARKS |
| Sensitivity | GAIN 100 |
| Processing Date | 08/30/2025 |
| Software Stack | Stellarmate OS, PixInsight, Affinity Photo |
| Capture Place | Koblenz, Germany |
Conclusion
With over 40 hours of exposure and careful technical execution, this astrophotograph of Sh2-119 represents a major milestone in my astrophotography journey. The combination of precise guiding, high-quality equipment, and patient work over several months produced a result that showcases the beauty and complexity of this nebula complex.