Abell 21 – Medusa Nebula
Abell 21, known as the Medusa Nebula, is a planetary nebula located in the constellation Gemini, near the border with Canis Minor. It is a very faint object, with an apparent magnitude of +11.30, an apparent size of 12.4 × 8.5 arcminutes, and an approximate distance of 1,500 light-years.
General information
- Constellation
- Gemini
- Category
- Nebulae
- Date
- 28 January 2022
Capture
- Total time
- 2h 35min
- Subframes
- 300s (light frames: 31x) ISO 1600
- Gain / Offset
- 0 / 0
- Calibration
- 20 dark frames, 50 flat frames, 50 dark-flat frames and 50 bias frames
Equipment
- Telescope
- TS102 f/5.6
- Camera
- modified Nikon D90
- Filters
- Ha+OIII/Hb
- Mount
- HEQ-5 Pro belt drive
- Guiding
- PHD2, Guide scope 60mm/f4 + ASI224MC
Processing and environment
- Processing
- Stacked and post-processed with PixInsight 1.8
- Acquisition
- NINA
- Location
- l'Ampolla
- Sky
- Bortle 4