Pausing to Recalibrate

Ideas more or less related to teaching and learning physics at Luther College.

It seems appropriate to reflect on our research work two weeks into the summer student projects. This summer I have six students working on three projects. It’s the most I have had at one time and we are off to a great start. The students are working in pairs on the three main projects areas we have ongoing: timing eclipsing binary minima, searching for rare stellar flare events and looking for secular evolution in long-period pulsating variables. In this last project we have spent most of the summer so far working on testing nightly normalization of the stars in field and developing a new way to complete that calibration. We are always working on data normalization.

A little while ago I wrote about how my teaching interacts with my administrative duties, claiming that the teaching is simultaneously draining and restorative. I suppose that the research/administrative work shares a somewhat similar relationship but it feels skewed toward the frustrating end of that spectrum. To be sure, the rhythm of taking data every clear night serves the restorative function but making progress on understanding a problem or working through analysis requires a kind of focus over longer blocks of time, the kind of dedication to task that I must provide elsewhere currently. Last fall we encountered a potentially interesting and wholly unexpected result in our long-period variable secular evolution study. That surprise led to the current investigation into our normalization technique, with a particular emphasis on the regions where we acquired new equipment. Nothing is lonelier than thinking that maybe you have seen something and deciding when the checking and re-checking is sufficient.

In January or February the re-calibration effort in turn led to a surprising result but we have idled since then as I lacked the time to make progress happen until the students could start working full time this summer. Our prior normalization protocol was good enough for what we were trying to accomplish early on, before we began thinking about long-term trends in our pulsating stars, really before we even knew we had a bunch of long-period variables in our field. Now, however, we are looking at trends at the level of a few percent over a decade. The data from the last couple years of that decade were acquired with new equipment that we may or may not have calibrated in at a level that doesn’t bias the fits that detect the few-percent trend. In this case a very small tail can wag a pretty big dog. So we are fiddling with the normalization, again. It is work that I would like to have done four months ago but simply could not give it the focus it required. Still, it is good work for the summer and the students have made remarkable progress in two weeks. I just hope they get all the data re-calibrated before we realize the next change in calibration we need to try.

{ Return to Physics Faculty Blog for more posts. }

Add a comment

Name*
Comment*
The following fields are not to be filled out. Skip to Submit Button.
Not Comment
(This is here to trap robots. Don't put any text here.)
not URL
(This is here to trap robots. Don't put any text here.)
Avoid
(This is here to trap robots. Don't put any text here.)