Continuing our series of images taken by students in “Advanced Observational Astrophysics” running Fall 2020, here are two color palettes showing off the beautiful Helix nebula, by Ross Silvers ’22.
Ross explains: “Pictured above is an image of the Helix Nebula (NGC 7293) created from a 16’’ telescope and CCD. We took eleven exposures at 120 seconds each for emission lines in each filter (Hα, OIII, and SII) from ionized gas in the nebula. Emission spectroscopy allows us to read electromagnetic radiation from chemical elements in an astronomical object. In this case, we were able to compile the images and assign pigmentation to each emission filter to create a full color image. Classically, red, blue, and green colors are assigned to each layer, but I chose to create a different image, using magenta, yellow, and cyan. The first image shows Hα in magenta, oIII in cyan, and sII in yellow. The second image has Hα in yellow, oIII in cyan, and sII in magenta, for a slightly different composite image. Sometimes, the Helix Nebula is nicknamed “The Eye of Sauron” as a reference to the Lord of the Rings addressing the eye-like shape of the nebula!”