Click on Image to switch to Annotated View.
M4 Globular Cluster & SH2-9 Emission Nebula
When summer comes to northern hemisphere, the vast Rho Ophiuchi cloud complex, the closest star-forming region to Earth, become one of the primary targets for Astrophotographers, as it holds objects for widefield and narrowfield imaging all the same. And this image is no exception, as it captures two very distinctive objects, packed very close together, but only to observable eye.
The globular cluster, called M4, is one of the two closest globular clusters to our Solar System (second one is NGC6397) and lies at about 7000 Light Years away, while red emission nebula SH2-9, lies about 600 Light Years away. So although they look very close in the image, they have very distinctive distance from each other. Globular Clusters believed to be as the oldest objects in our Galaxy and in case of M4, it's about more than 12 billion years old, almost as the known Universe itself. M4 cluster is wide as 75 light years across and contain tens of thousands of stars in it.
On the other side, we have a good example of combination of both, emission and reflection nebula – SH2-9. The nebula surrounding bright, multiple star system, Sigma Scorpii, which causes the bluish colors of reflection part of the nebula in the center. The emission part of the nebula, is a surrounding glowing clouds of excited hydrogen gas, which brings distinctive red colors to it. This emission part of the nebula is best captured with H-Alpha filter, which brings more details and shows clear structures of those hydrogen clouds It is believed that Sigma Scorpii is directly responsible for ionizing this whole area.
Optics : Takahashi FSQ106-EDX4 @ F3.6 @ 380 mm (645x0.72)
Camera : QSI 660 WSG-8
Filters : Astrodon Gen 2 E-Series - HaLRGB Filter Set - 1.25"
Mount : NEQ-6 Pro (Self Hypertuned/Belt Mod)
Guiding: QSI OAG + SX Lodestar X2
Acquisition : Sequence Generator Pro (188.8.131.520)
Exposure : Lum (1x1) - 75 x 120 2 Hours 30 Minutes
R (1x1) - 44 x 120 1 Hour 28 Minutes
G (1x1) - 44 x 120 1 Hour 28 Minutes
B (1x1) - 44 x 120 1 Hour 28 Minutes
Ha (1x1) - 11 x 600 1 Hour 50 Minutes
Total Exposure: 8 Hours 44 Mimutes
Processing : PixInsight 01.8.8-8