M8 — Lagoon Nebula

About

The Lagoon Nebula, a large emission nebula in Sagittarius, roughly 4,000 to 6,000 light-years away, one of two star-forming regions visible to the naked eye from mid-northern latitudes. The young cluster NGC 6530 sits inside it.

Imaging tips

• About 90′ × 40′, so it fits a 150′ frame at 270–450 mm on APS-C (410–690 mm on full frame).
• M20, the Trifid Nebula, is about 83′ away; one write-up framed the two together in a single shot, with NGC 6530 on the left side.
• Two approaches worked: 8 hours of 300 s subs with a one-shot colour camera and no filter under a Bortle 2 sky, or 3 hours of 180 s subs in Hα, OIII and SII.
• The same imagers found their first narrowband version too green and reprocessed it for a more natural colour.
• Low in the sky: it stays below 16° altitude from 50°N, so avoid city glow to the south. Best in June and July.