The Corona Australis Molecular Cloud
Infrared-Visible Composite image using IR data from the
Wide-field Infrared Survey Explorer (WISE)
The Corona Australis Molecular Cloud is a dusty nebula and star-forming region with both reflection and absorption components. This image here has a combined exposure of 4.5 hours of data, shot under very good sky conditions in Flinders Ranges, South Australia, and Mersing, Malaysia. NGC 6723, an ostensibly adjacent globular cluster (but in fact much farther away from Earth than the nebula), is also visible here on the top right of the blue reflection nebula, NGC 6726/67.
The second image depicts the molecular cloud as a Visible + Infrared composite. The infrared data is credited to NASA's Wide-Field Infrared Explorer (WISE) space telescope, which is available from archives online. The infrared data used has a wavelength of 3.4 micrometres, corresponding to the shortest wavelength band from the WISE telescope. Since infrared light is strongly absorbed by the Earth's atmosphere, infrared telescopes are almost exclusively in space-based or air-based platforms. The purpose of adding infrared data into the original image is to show the stars which were otherwise obscured by the absorption nebula. Since longer wavelengths are not scattered as much as shorter wavelengths, longer wavelengths (in this case infrared light) can be used to peer into the otherwise opaque (in visible light) dust clouds.
Location: Flinders Ranges, South Australia and Mersing, Malaysia
Date(s): July 2016 and July 2017
Telescope: Takahashi FSQ85ED at f/5.3
Camera: SBIG ST8300M
Mount: Losmandy G11/G2
Exposure Integration: 4.5 hours in LRGB
Credit: NASA Wide-field Infrared Survey Explorer (WISE)
Bandpass centre wavelength: 3.4 microns
Image reduction, integration and processing with Astro Pixel Processor and Pleiades Astrophoto PixInsight.