Sh2-1
HII Region in Scorpius
About
A blue reflection nebula mixed with red hydrogen glow in Scorpius, curving through roughly 180° around the star Pi Scorpii. It lies about 650 light-years away and sources give its size as about 150′, more than two degrees across.
Imaging tips
- At about 150′ it fills a third to half of the frame at 160–270 mm on APS-C (250–410 mm full frame); go wider for its surroundings or plan a mosaic.
- The blue reflection part needs broadband colour. One imager added a 3 nm Hα filter to LRGB to bring out the red emission.
- One imager collected 60 frames of 300 s (about 5 hours) with a one-shot colour camera; another logged 9.8 hours of LRGB with luminance taking the largest share.
- Sh2-7 lies just above it, and an Hα wide-field image shows both together.
- Best in May and June, but it stays below 13.9° altitude from 50°N; one imager noted the target sat low in the sky.
Facts
- Size
- 150′
- Magnitude
- —
- Coordinates
- RA 15h 58.8m, Dec −26° 7′
- Framing, APS-C
- 160–270 mm
- Framing, full frame
- 250–410 mm
- Best months
- May, Jun
- Peak altitude
- 14° from 50°N, 29° from 35°N