Bias and Dark Subtracting
The Dark Frames capture the dark current, a charge created by thermal electrons that builds up over the durations of an exposure. It also can identify hot pixels, pixels with abnormal thermal efficiency. As the value of pixels in dark frames increases over time, to achieve the most accurate final images, dark frames need to be taken at the same exposure time as the target images. If darks are not taken at the correct corresponding exposure, the correct Dark Frames can be approximated by linearly scaling the pixel values with the length of exposure. – 337 Final Project (Cat & Alex)
I began by zipping and downloading the raw data frames as well as the dark frames from the iTelescope FTP server. They zipped in a manner where I had to write some semi-recursive code to unzip all the files and relocate them to a single folder. I was then able to use most of my 337 code to create a master dark (without bias subtracting it) and then subtract the dark from all the relevant science images.
As the exposure times and bands are given in the headers, my code worked for the most part and a lot of the foresight and generalization I had in 337 paid off quite a bit. As seen in the images below, the bias subtraction removed some vignetting (the rest will be done by flats) and generally reduced some of the noise in the images. The main difference, quantitatively, is that the counts dropped from around 2700 to about 850. This reduction is expected and a good logical test to make sure the code is working properly.

Annotated Bibliography
Project Feedback
Last Tuesday I received generally positive feedback on my project proposal draft. There wasn’t anything major I felt like I needed to change or revise, so I began thinking about general next steps. I think I am still in the knowledge gaining phase. I want to read a few more papers about star spots and maybe ask some more questions at a future office hours session. I have learned a lot about them since I chose this project, but I think I have a bit more to go before I feel as though I can write confidently on them in the form of a proposal.
Project Paper
The additional paper I chose is titled Early Cluster Evolution and the IMF by Fred C. Adams of the University of Michigan. It’s a little old, but it gives a pretty straightforward definition and introduction to an IMF and why they are important in galactic astronomy. As I am the only person in our group of three that has not taken Astrophysics III or any galactic astrophysics, I think it’s important for me to catch up a bit on the actual underlying physics to our project.
The paper also covers the formation of clusters and the mechanics by which they form as well as the relative ratios of specific stars forming within them. If there are any other papers, possibly review papers, that might make sense to read to catch up on any of this material, I would be happy to learn about them.
Conclusion
I’m so happy with my group and excited to dive into the final project for the course! I think ours is going to be so strong and I know I’m going to learn so much along the way.