Blogs / Aaron Price's blog / Egress light curve from visual, photometric and student sources
Egress light curve from visual, photometric and student sources
This semester the Tufts University introduction to astronomy class observed epsilon Aurigae as their course lab. The class has around 250 students and they do not have access to equipment for a formal lab. So epsilon Aurigae was perfect since it is bright enough to be seen from campus with the unaided eye and happens to be emerging from the eclipse. They were tasked to observe once every two weeks and report their data to Citizen Sky.
The above light curve includes all Citizen Sky data since February 1, 2011. The blue line is the 7 day mean curve based on data only from Tufts students. The red line is the 7d mean for visual observation from non-Tufts Citizen Sky participants and the green line is for photometric observations from Citizen Sky participants.
As you can see, the Tufts students agree well with the overall Citizen Sky participants. They have a higher dispersion in the beginning, which is expected considering they were brand new observers. After about a month their dispersion is only slightly higher than the non-Tufts participants. Indeed, the mean curves of all the data are almost identical in that the visual data mean falls just barely within the error bars of the photometric data.
Congrats to the Tufts students and to all the Citizen Sky observers, visual and photometric. Please keep up the drum beat as we head out of the eclipse. Observations will be needed throughout the year to help characterize the out-of-eclipse variation.
If any other instructors would like to use variable star observing in their labs, please contact us. There are a number of bright variables that can be observed in short time spans throughout the year.
Hi Aaron The Tufts students actually did submit obs in the range from 0 to 23 mag (averages, error bars and connecting line in blue, ´validated data points in gray). Judging from the blue error bars, you must have exclude their obviously worst discrepant obs to give such small error bars. But two of theerror bars of theCitizen Sky participants' data are very large andmust have beendistorted by obvious outliers too (if its not a computing error). Did you check which obs did cause the error bars to be so large ? Could you, please, check the Citizen Sky participants' data, remove the obvious outliers too, and replot the graph ? Thx. Am I right that the green line is for CCD V and DSLR green channel data ? CS Wolfgang
Yes, some students reported grossly wrong errors. In most of the cases it was because they did not take the assignment seriously. In fact, in a couple of instances we caught students making up observations. The AAVSO validation process removes these data points. We applied the same process to this data that we apply to all variable star data we receive from anyone. The fact that we have more discrepant data than normal is not surprising since we had 250 students who had zero prior experience observing variable stars (or even in amateur astronomy at all).