Almost finished with our series of images made by students in the Fall 2020 “Advanced Observational Astrophysics” class.
Here’s an image made by Miranda Kong, BMC’22 using data of part of the Double Star cluster in Perseus I took over the summer.
Miranda explains: “We have used backup data for the Perseus Cluster taken by Professor Karen Masters at the Strawbridge Observatory with the 16” telescope and 4096×4096 pixels CCD. The images are taken in g, r, and i filters.
I have produced the 3-color combined image using the data. For the combination process, since the i filter indicates infrared wavelengths, I have assigned the color red to the i-filter images. Therefore, my color scheme is shifted, so I need to assign magenta to r (red), and cyan to g (green), i.e. the whole spectra is shifted blue for a little. This produced a decently balance image of which I could adjust the 3 filters to form an image of black background, and stars predominantly white. However, some of the star do appear more red or more blue (especially the small ones) than others. Since these data are just taken with gri filters, a star appearing more blue in this image simply says that it emits more blue light than other colors, i.e. its color spectrum peaks at blue. By black body radiation, we know that hotter stars tend to peak at the bluer end of the spectrum. ”