Sh2-9
HII Region in Scorpius
About
A red emission nebula blended with blue reflection nebulosity around Sigma Scorpii, a multiple star system in Scorpius about 568 light-years away. The variable giant in that system is thought to ionize the gas, and small telescopes can show it.
Imaging tips
- At 270–450 mm on APS-C (410–690 mm on full frame) it fills much of a 150′ frame.
- M4 lies about 1° from Sigma Scorpii and Antares about 2°, so a wider field is needed to include them.
- In one Hα wide-field image, Sigma Scorpii's red glow tops a frame that also takes in Antares, M4 and the neighbouring vdB 104.
- Best in May and June; it stays below 14.4° altitude from 50°N.
Facts
- Size
- 90′
- Magnitude
- —
- Coordinates
- RA 16h 21.2m, Dec −25° 36′
- Framing, APS-C
- 270–450 mm
- Framing, full frame
- 410–690 mm
- Best months
- May, Jun
- Peak altitude
- 14° from 50°N, 29° from 35°N