Amateur Photometric Distance Measurements for Type Ia Supernovae

I began thinking about what I wanted to research in the spring of 2025. I eventually landed on my first solid idea. I thought that with my computerized telescope, I could take spectra of protostars inside star forming regions/nebulae. This turned out to be quite difficult. It was expensive and not feasible. Over the summer, I began to image galaxies and nebulae on clear nights. One night in late June, I imaged the galaxy NGC 7331, a local galaxy that isn’t unlike the Milky Way. It was a nice image, though nothing I was too proud of. But, on July 14th, a supernova was discovered in that galaxy which gave me the very rare opportunity to capture my own image before and after the supernova. So on July 25th, I briefly imaged the galaxy again. August 2nd is when I took the first solid, photometrically valid image. By then, I realized that using the knowledge of cosmology from years prior, my project could be about photometry and supernovae. After thinking about it a little more, doing some research, and taking a few more images throughout August and September, I landed on my topic: can amateurs perform accurate differential photometry on supernovae to determine the distances to their host galaxies?

Comparison of NGC 7331 before the supernova, when the supernova occurred in late August, and when I last imaged it in September

Image of the supernova 2025rbs on September 18th