Description
These Sandqvist dark nebula are part of the large, western Circinus Cloud complex that is about 2 x 5 deg. North is up, east is left and the image is 2.8 x 2.8 deg. The darker, filamentary nebula toward the west (middle right) is comprised of Sandqvist 169, 170, 166 and 171. The larger, dark nebula toward the east (center and left) is Sandqvist 172. It is suggested that the filamentary structures result from outflows from numerous young stars. This image was made with RGB and H-a filters. It contains about 8500 stars. An annotated version is presented below:
Exposure: 9.33 hrs Total; 2 hrs each RGB, 3.3 hrs H-a
Telescope: Takahashi Super-Reduced TOA130 760 mm f/5.8
Mount: PlaneWave Ascension A200h
Oag: SBIG ST-402 on BORG AG50B 2" Guide Scope
Acquisition: ACP-8 Expert
Calibration: CCDStack v2
Observatory Site: iTelescope.net, Siding Spring, NSW, Australia
Telescope: Takahashi Super-Reduced TOA130 760 mm f/5.8
Mount: PlaneWave Ascension A200h
Oag: SBIG ST-402 on BORG AG50B 2" Guide Scope
Acquisition: ACP-8 Expert
Calibration: CCDStack v2
Observatory Site: iTelescope.net, Siding Spring, NSW, Australia
Camera: SBIG STX16803
Filters: Astrodon 5 nm H-a, E-Series RGB
Guider: SBIG ST-402
Camera Operation: MaximDL 5.24
Processing: Photoshop CC 2017
Image Date: 07/25/2017 - 07/27/2017
Filters: Astrodon 5 nm H-a, E-Series RGB
Guider: SBIG ST-402
Camera Operation: MaximDL 5.24
Processing: Photoshop CC 2017
Image Date: 07/25/2017 - 07/27/2017