NGC6888 – Crescent Nebula (Caldwell 27)
NGC6888, known as the Crescent Nebula, is an emission nebula in the constellation Cygnus. It has an approximate visual magnitude of +7.4, an apparent size of 20 × 10 arcminutes and lies about 4,700 light-years away. The exposures were captured on the nights of 10 and 16 June 2022 and 24 August 2023, at temperatures between 22.0 and 24.75 °C, with the object at elevations between 33° and 68° and the Moon aged 10 and 16 days.
General information
- Constellation
- Cygnus
- Category
- Nebulae
- Date
- 24 August 2023
Capture
- Total time
- 7h 27min
- Subframes
- 300s (Ha: 19x) bin1 + 240s (CLS: 45x) bin1 + 240s (R: 14x, G: 14x, B: 15x) bin2
- Gain / Offset
- 125 / Not specified
- Calibration
- Not specified
Equipment
- Telescope
- TS102 f/5.6
- Camera
- ZWO ASI294MM at -5 °C
- Filters
- Ha, CLS, R, G and B Astronomik
- Mount
- Sky-Watcher HEQ5 Pro with belt drive
- Guiding
- PHD2, Guide scope 60 mm f/4 + ASI224MC
- Focuser
- Not specified
- Filter wheel
- Not specified
Processing and environment
- Processing
- Pre-processing, stacked and post-processed with PixInsight 1.8.9
- Acquisition
- NINA
- Location
- l'Ampolla, Tarragona
- Sky
- Bortle 3–4
Annual visibility
164 days per year above +30° at 00:00 UTC from 41° N, 1.5° E.