This project is an interesting one because the finished product will require a compilation of many different regions of the sky. For now, I’ve finished the central region of NGC6523 and the remaining outlying regions will take a year to finish (I suspect). The Lagoon Nebula (catalogued as Messier 8 or M8, and as NGC 6523) is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and as a H II region.
The nebula contains a number of Bok globules (dark, collapsing clouds of protostellar material), the most prominent of which have been catalogued by E. E. Barnard as B88, B89 and B296. It also includes a funnel-like or tornado-like structure caused by a hot O-type star that emanates ultraviolet light, heating and ionizing gases on the surface of the nebula. This creates a structure known as the Hourglass Nebula (so named by John Herschel). To give you an idea of the size of a Type O star in comparison to the Sun, the following picture shows the scale. The Sun is a Type G star on this list. It’s a huge difference. Type O stars typically explode violently and leave black holes in their place.
The finished produce has been taken with a GSO RC12-A, approximately 12 hours of exposure guided with an SBIG ST-ic using off-axis guiding on a Paramount MX. Data captured with Nebulosity, post processing with MaximDL, Nebulosity and GimpShop on Ubuntu. I have a finished picture and one which shows the highlights of the region in M8.
Here’s the finished shot:
And here’s the shot with interesting regions highlighted.
The funnel-like or tornado-like structure caused by a hot O-type star that emanates ultraviolet light, heating and ionizing gases on the surface of the nebula creates a structure known as the Hourglass Nebula (so named by John Herschel), this is shown in detail at section A of the photo.
Section B of the photo is NGC6530, an open cluster of stars thought to be only a few million years old. This is relatively young in interstellar age.
History and mythology of Messier 8: While the fanciful name Lagoon might suggest a mythical origin, there is no known mythology associated directly with this interstellar cloud. The name apparently refers to the shape with the dark lane through the middle, not unlike two lagoons separated by a sandbar. While visible to the unaided eye and therefore certainly seen in antiquity, there is no known mention of this nebula until 1654, when Sicilian astronomer Giovanni Battista Hodierna recorded his observations of the star cluster within the nebula. The area was observed by several other astronomers, including Charles Messier in 1764, after which it ultimately also became known as Messier 8, or M8, the eighth object in Messier’s catalog.
Messier 8 science: M8 is about 5000 light years away, and roughly 130 light years across in the longer dimension. Composed primarily of hydrogen, much of it ionized (heated or energized) by radiation from the nearby superstar Herschel 36, M8 is known as an emission nebula. As such it also is a star-forming region, sometimes called a “stellar nursery.” There is an open star cluster, NGC 6530, of young, hot, blue stars probably only a few million years old. In addition to these young stars, there are also many dark “Bok” globules of condensing gas and dust on their way to becoming “protostars” and ultimately full-fledged stars like those already formed nearby.
As a point of interest, here’s the difference between a year or so of processing experience and a new scientific instrument. The Lagoon Nebula from 2013 using a Celestron 9.25 xlt SCT (you can see the difference from the GSO RC12-A above):