Sh2-240 — Simeis 147
Supernova Remnant in Taurus
About
Simeis 147, the Spaghetti Nebula, a supernova remnant on the Auriga-Taurus border about 3,000 light-years away and some 3° across. Grigory Shajn's team found it in 1952 with a Schmidt camera. It is about 40,000 years old, and a pulsar is believed to sit in its core.
Imaging tips
- Its 3° span calls for 130–220 mm on APS-C, or 210–340 mm on full frame, to fit the whole shell.
- Brightness is extremely low, so very long exposures are needed; narrowband filters bring out the filaments.
- One imager collected 52 hours with 300 mm lenses: 32 half-hour subs each of Hα, SII and OIII, plus short LRGB for the stars.
- The small nebula Sh2-242 sits near the edge of a wide frame centred on the remnant.
- Best in December, peaking near 68° altitude from 50°N.
Facts
- Size
- 180′
- Magnitude
- —
- Coordinates
- RA 5h 41.1m, Dec +28° 5′
- Framing, APS-C
- 130–220 mm
- Framing, full frame
- 210–340 mm
- Best months
- Dec
- Peak altitude
- 68° from 50°N, 83° from 35°N