Saturday, May 31, 2014

Variable Star Notes - Neglected Eclipsing Binaries

  Since the last post I've had some nights of meteor observing and a couple of opportunities to get the 10" scope out to do some lunar photography, but I haven't done too much else. With meteor activity at a lull early in the summer, I'm starting to get interested in variable star observing again.

  My enthusiasm for doing this kind of amateur astronomy has waxed and waned a lot in the past few years. When I joined the AAVSO way back in 1984, making visual estimates for variable stars was still the "norm" since CCD technology was in its infancy and there was still no such thing as the Internet. However, especially in the last decade or so, I've started to have my doubts about whether there was any value to making visual estimates at the telescope eyepiece any more. CCD cameras, when used properly, can see stars much fainter than the human eye can, and they can make measurements much more accurately. This kind of data seems to be preferred now by professional astronomers. Also, there have been several automatic all-sky surveys launched in the last decade that can cover the whole sky every few nights, and make very accurate measurements of the brightness level of many variables. It's seemed more and more clear to me that visual observing is something obsolete and that most professional astronomers think it's "quaint." Why try to make estimates of Miras or Semi-Regular stars when the automatic cameras record these things weeks at a time? And for that matter, why try to make estimates of an eclipsing binary going in and out of eclipse when someone taking images with a CCD will probably be gathering much more precise data at the same time?

  The answer to me is this ... cover the things that the all-sky cameras and the CCD users aren't covering! Try to find a niche that no one else is paying attention to.

  This was one of the reasons why, a few years ago, I started to get interested in YSO's. Young Stellar Objects can show very rapid and random light variations that the all-sky automatic surveys might not be able to catch. For example, I've seen UX Orionis fade from a star that can be easily seen in the 10" scope to a star that can be barely seen in just two or three nights, and an all-sky survey camera might catch the fact that it faded, but it wouldn't be able to see how much the brightness decreased night by night like I could at the eyepiece of my own telescope. It also wouldn't catch if UX Orionis had any brief brightening before resuming its fade during the time it wasn't imaging that part of the sky.

  I have always loved watching Eclipsing Binary Stars also, but again, the CCD users seemed to have taken over this area of variable star observing and left the visual estimators like me out in the cold. However, I started to realize last year that there are a lot of these stars that are under-observed, and that this could be a valuable field of research to pursue.

  I started with two "neglected" Eclipsing Binary Stars last summer; DF Pegasi and SY Andromedae. By the fall I was also looking at the rarely observed V1380 Orionis, which is very close to the nebula M-78. I plan to start observing these in a much more systematic way this year, and also start researching, making charts for, and observing several other stars of this type.

  In the last week I've made comparison sequences for two eclipsing binary stars near Delta Cephei, KL Cephei (which goes into eclipse every eight months and hasn't been recorded by anyone since October 2008) and OT Lacertae (which has a totally unknown period and ... get this ... hasn't been observed by anyone as far as I can tell since 1954!) I'm going to be adding more stars to my list of neglected eclipsing binaries soon and hopefully getting out to observe them when I can.

  This first half of June will find me working First Shifts at my job, and with these short nights, both evening and predawn observing is going to be next to impossible. However, by the second half of June through early July I'll be on Second Shifts, and, if skies are clear, I'll be able to get some predawn observing done during those weeks. In the meantime, I'll be posting some notes about some of these stars to this blog.

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