Around the Sky in 28 Days – Day 7

The Moon is now a day past First Quarter or when it appears half Full in the evening sky. It is also getting bright enough that it is hard to see some of the objects nearby. Still this evening the Moon can be used to locate one of the most easily observable star formation regions in the sky.

Called the Lagoon Nebula (also known as NGC 6523, Messier 8, or M8 for short), it is a region of gas and dust stretching across 140×60 light-years at a distance from Earth of 5,200 light-years. All of these numbers are somewhat uncertain so errors up to 10-20% should be assumed. Much of the energy powering the “glow” of the nebula is produced by a cluster of stars which is currently forming from the nebula.

The image below shows the Lagoon in all its glory. Unfortunately this is not what it looks like to any human being. The picture is the result of long exposures on a large telescope. For most of us the Lagoon complex will appear as it does in the finder chart above. To the unaided eye the Lagoon is visible as small faint cloud though that is only true from dark sites. With the Moon so close even dark site observers may not be able to see it without help. oTo really see the Lagoon point a pair of binoculars or a small telescope a few degrees to the right of the Moon. A line of 5th-6th magnitude stars are superimposed on the Lagoon. Within this line of stars you may make out the Lagoon’s associated star cluster sand perhaps the inner core of the nebula itself.

Image of the Lagoon Nebula and associated star cluster. Image taken as part of the GigaGalaxy Zoom project with the MPG/ESO 2.2-m telescope. Credit: ESO.

Tomorrow – Day 8 – Moon in a Teapot.