Justin Timberlake
Where are the new tunes, I need
Some new JT please
So far this week I’ve reduced the rest of the data and attempted to make a light curve with my Praesepe I-Band stacks. I got astro-IMGJ to work on the UMass computers following the steps from class, but I am not picking proper references or targets. Right now I am just freestyling as I don’t really know where the brown dwarfs are. When trying to cross-check with my region file of the cluster created a couple weeks ago, i could not successfully open it in DS9. I think it has to do with the region ‘uploader’ is trying to upload the file in physical/image coordinates as oppose to FK5 which the file is in. Right now I can’t find a way to change the settings, I hope that my OOC meeting can help in this regard.
OOC meeting was very helpful. I have learned that my shifts are too big. I am aligning them to a different reference image as I am typing. Tonight I think I will make all night stacks and run one through astrometry to I can make a proper light curve tomorrow.
These are the results for last weeks class that Savio and I got:
These results are really interesting. There is a super regular period shown in the lightcurve to the right. Considering this was kinda a shot in the dark I was surprised it worked so well on the first try. Hopefully I will be as fortuitous tomorrow making the lightcurve on my own data. As we can see the difference is magnitude is only about 0.025 magnitudes, but a very clear oscillation. AstroimageJ is a super nifty program that takes in a series of images and performs ensemble photometry for you. It takes into consideration all of the technical notes of the instrument that you took data on, as well as pixel value saturation/non-linearity values etc. in order to run differential photometry on a target and as many comparisons as you’d like to plot a lightcurve. Even though it is seemingly intimidating for our purposes it is pretty straight forward to use. Frankly it is impressive this was put together by one or two astronomers. My cap off to them.
Making a lightcurve went alright. My test one is shown below. There appears to be some variability, but nothing too regular. My first instinct is that the comparisons were not chosen too wisely. I was trying to pick sources outside of the cluster members to get an object that is relatively constant in magnitude across our image set. Alas, i have made a curve and seen what I saw. I know that this is not our method to perform photometry on our data so I’m not gonna trip about it. My image with the cluster members circled is also shown below.
Aligning so far is going well. There is still some issues with shifts greater than 100 pixels in an axis for some stacks. Should I pick another reference image. I’m realigning another night right now so we will see if it remains to be a significant drift. Some TESS images have huge shifts. We might need to consider changing reference images.
Cassidy and i have compared our reduction and it seems they resemble eachother well enough to reproduce data products. Which is all we need. Our shifting methods are the same, but our trimming differs a bit. I trim to a square 4096×4096 while Cassidy trims to a rectangular 4110 x 4095. This is something that we should keep in mind but i don’t think will produce too many roadblocks in themselves. We have a similar median count for our test images of about 150 a piece. Overall it appears we are on the same page and should proceed as we have for the last few weeks. The next step in our reduction is to make deep stacks. I have been tasked with the TESS field as it has less data and Cassidy’s machine has more computing power than mine so she will take the brunt of the force. Then hopefully we can do lightcurves in Python and start making some measurements.
Owen H. ASTRO-341 Research Blog 