Sh2-7
HII Region in Scorpius
About
A large, faint hydrogen emission nebula in Scorpius that surrounds the star Delta Scorpii, about 650 light-years away. Wikipedia gives its apparent size as 240′ by 240′, four degrees across, which makes it much wider than most telescopes can frame.
Imaging tips
- At about 240′ it fills a third to half of the frame at 100–170 mm on APS-C (150–260 mm full frame); go wider for the surroundings or plan a mosaic.
- It is an emission nebula, so Hα suits it; the wide-field Hα image in one catalogue shows it centred at the image edge.
- Sh2-1, the blue reflection nebula, sits just below it in that same wide Hα field.
- Best in May and June; it stays below 17.1° altitude from 50°N.
Facts
- Size
- 240′
- Magnitude
- —
- Coordinates
- RA 16h 0.6m, Dec −22° 56′
- Framing, APS-C
- 100–170 mm
- Framing, full frame
- 150–260 mm
- Best months
- May, Jun
- Peak altitude
- 17° from 50°N, 32° from 35°N