Today’s student image from the Advanced Observational Astrophysics class is a purple view of the Pelican Nebula, by Kate Matthews ’22.
Kate explains: “The image above is of the Pelican Nebula (IC 5070), a nebula with magnitude 8.0 located 1,800 light years away from Earth in the constellation Cygnus. This color image consists of 30 individual overlaid images with an exposure time of 120 seconds each, giving the final image a total exposure time of 1 hour. These images were taken with the CCD on the 16” telescope at the Strawbridge Observatory on September 20, 2020.
The Pelican Nebula is an HII region, meaning it is an emission nebula made up of gas clouds ionized by very hot, nearby stars. To capture several different ionized gases in the nebula, we used 3 emission line filters when taking the images: Hα, OIII, and SII, which refer to ionized hydrogen, doubly ionized oxygen and ionized sulphur, respectively. Each filter was assigned a color when creating the final composite image, specifically magenta for Hα, green for OIII, and blue for SII. Due to the large amount of energy required to ionize hydrogen, Hα emission is a common indicator of new star formation.”