Messier 16
The weather here has been pretty poor lately - lots of cloudy or very cold nights (with lots of condensation and damp) that don’t really inspire me to get outside and start imaging.
There are a few targets that are only visible to me for a few months of the year, and M16 (Messier 16) is one of them. It goes by a swag of other names, so you may be used to seeing it called something else.
According to Wikipedia:
The Eagle Nebula (catalogued as Messier 16 or M16, and as NGC 6611, and also known as the Star Queen Nebula) is a young open cluster of stars in the constellation Serpens, discovered by Jean-Philippe de Cheseaux in 1745–46. Both the “Eagle” and the “Star Queen” refer to visual impressions of the dark silhouette near the center of the nebula, an area made famous as the “Pillars of Creation” imaged by the Hubble Space Telescope. The nebula contains several active star-forming gas and dust regions, including the aforementioned Pillars of Creation. The Eagle Nebula lies in the Sagittarius Arm of the Milky Way.
Of course, it wouldn’t be astrophotography without something going wrong. Not only did my autofocus system not want to work properly, but the controller for my dew heater decided it wanted to melt itself. It’s always alarming to smell melting plastic and self-combusting electronics, and even more so when it’s near some expensive equipment.
I was able to get the electrics sorted out, but I knew that without a dew heater condensation on the telescope lens would put a quick end to the night’s imaging. I’ve purchased some new electronic bits, which will be the focus of another article when they’re all sorted out and operating as they’re supposed to.
I wasn’t confident that I’d get a good image out of this, but pressed ahead and processed the data anyway. It was surprising to see the end result - the colours are good, there is an acceptable level of detail in the gas / dust clouds, and you can see the ‘Pillars of Creation’ quite clearly.
The processing workflow was the same as always - stack and pre-process in Siril, then use starnet++ to separate the image into stars / starless layers for further processing and then recombining with Siril and Affinity Photo.
I’m hard-pushed to decide which one I like the best, as I like elements of both of them…
Image data:
- Gain: 100
- Offset: 10
- Temperature: 0 degrees C
- Exposure: 120 seconds
- Frames: 68 Lights, 25 Darks, 25 Flats and DarkFlats (2 hours and 16 minutes integration in total)
- Filter: L-Enhance (Ha + Oiii dual-narrowband)
Equipment: SW72ED@420mm / HEQ5-Pro / ASI183MC-Pro / SV165+SV305 / Kstars/Ekos
This image is darker and somehow “moodier”, which draws out some of the detail hidden away in the brighter parts of the nebula’s core; but at the cost of easily seeing the details in the outer part of the gas and dust clouds.
The second image gives you better views of the details and patterns in the nebula’s outer regions, at the cost of a slightly over-exposed central region. As I said above, I like them both for these reasons.