Today I started off with a bit more tinkering of parameters on the second image. I was able to get the subtracted image looking a little better, but not much. We've determined one of the biggest causes of error is that the focus wasn't consistent across the CCD. In reality, this is pretty typical given that every telescope design has some sort of inherent abberation. It's also entirely possible that the CCD wasn't perfectly aligned with the focal plane.
Either way, the best subtraction seems to be in the center. Towards the top it's a bit off, and for the bottom it's quite poor. Once I finished the second image, Dr. Sandquist advised me to go ahead and process the rest of them since I seem to have found the settings that work best.
At 11:00, Dr. Sandquist gave us a brief presentations on giving presentations since we have to do that Friday. Although he recommended a few things I didn't have, I think I'm going to ignore them. For instance, I don't really feel it's necessary to have a summary slide for a 5 minute presentation. I don't think anyone's memory is that bad.
I also spent a bit of time today trying to identify the single variable star Crinklaw & Talbert identified amidst the few thousand stars in the images. To do so, I took the finding chart from their paper, printed it out, and tried to match it up with our images. If you'd like to play along, here's the images:
This is the finder chart. The variable star is identified by the red circle. It may help to click to view the image in full and print it.
Here's the actual image I'm working with (with a little photoshopping of the levels to increase contrast).
NOTE: Just as I had to deal with, the two images may not be the same scale, area, center, or orientation! It took me about 3 minutes to locate. How quickly can you do it?
If you need the answer, click here.
At this point, I took a break for lunch and decided to take a quick nap. Quick of course meaning a little over 2 hours. When I woke up it was almost time for dinner so I decided to spend the little bit of time before then making a few quick changes to my powerpoint as I've decided that there my be a bit too much information for a 5 minute presentation, and I should drop a slide or two.
I did, however, add a few slides at the beginning as a refresher on properties of open clusters since not everyone in the group has much astronomy background. Once I made these changes, I Emailed it to my advisor back in Kansas for approval.