1 good dinner + 1 good martini + 1 calmed brain = ready to blog less panicy
Dennis di Cicco is giving a talk on the history the building we are all sitting in. This is actually way more exciting than one might expect. Dennis is an editor at Sky & Telescope magazine, and S&T and the AAVSO have a very strangely interwoven history. Both orgs started at Harvard College Observatory. Both orgs had headquarters on Concord Ave (decades apart in time, but across the street from each other). They both (several decades apart) moved to the same 1 block area on what eventually grew into adjoining properties. They stayed next to each for about 20 years.
I’ve read these stories many times over the years, but this is the first time I’ve heard it told. Dennis is not just an excellent writer, editor, and observer, he’s also an excellent story teller.
One of the neat things about this history is S&T’s Bay State Rd. HQ was it started as the Editor in Chief’s, Charlie Fedderer personal home. He bought the property and built the HQ onto his house. Over the years, that original home eventually got converted into offices. AAVSO is no where near as big as S&T in terms of staff. We don’t fill this building up at all. These means the old house / converted offices are currently empty. One idea for our future for this building is to convert that once home into a future home. I find sweet symmetry in this possibility.
8:46 Joe Patterson “Cataclysmic Variables, Computers, and CCDs: The First 30 Years”
This is one of the big talks of the weekend. Joe has been playing the Cataclysmic Variable game since 1979. He’s basically been there, done that, and defined the field. Today Joe is a prof at Columbia University and is part of the Center for Backyard Astrophysics.
1979 was the year he started graduate school at my alma mata, the University of Texas. Working at McDonald Observatory, he used some of the very first photoelectric photometer to study cataclysmic variables. He was one of the first folks to do this work, and he was in the right place at the right place with the intellectual tools to discover that many stars have extremely short periods (order of tens of seconds) scattered across the sky. (Only DQ Herculis was known to do this before.)
Today about 50 of these stars, then thought to be white dwarfs with strong magnetic fields sucking mass off of companion stars into a disk of material.
After leaving Texas, PhD in hand, he wandered in various directions without the observational facilities he needed to continue his research. He tried, working within the national observatory system, giving academic talks to places that just didn’t really care about this new set of objects he’d been busy discovering. Luckily, a rather tenacious fellow Dave Skillman asked some good deep questions. Dave had a home built robotic observatory and he was willing to acquire photometry for Joe.
There were just 4 stars bright enough for this backyard observatory, and for many years they plugged and plugged away, until in the mid-1980s Dave built his own CCD camera. This allowed more stars to be observed. This new technology also had a much easier interface than photomultiers (Skillman’s old technology), and Joe and Dave sucked in more people, more telescopes, and started getting as many as 16 hours a night on individual objects as observers passed objects from one observatory to another.
Today there are observers scattered over North America, Europe, South Africa, Australia, and New Zealand.
So, the next great frontier, having conquered Earth, was clearly space. When a call went out for ballast for a Space Shuttle mission, they even got to launch a 12″ Meade into space. Their are some great images of the Solar Panel covered little optical package floating off to orbit above it’s backyard observers. Unfortunately, the little Meade was never able to establish contact with its parents, and today (unless it burned up) it makes solitary silent orbits.
That said, from these collaborations and equipment experiments, Joe and Dave and others built the organization, The Center for Backyard Astrophysics. They specialize in creating light curves of cataclysmic variables, and using the repeatable bumps at wiggles in their signal to study system dynamics.
He just said something that really caught my attention: Some Cataclysmic Variables are white dwarf – White Dwarf binaries. White Dwarfs are about the size of the moon, and these binary stsytems are small enough that they could fit inside Jupiter. The entire binary – both stars – could orbit one another inside an empty Jupiter sized sphere.
Now that isn’t something I’d never put together, and it is really cool.
In addition to CV work, they have also found some exoplanets, gravitational lensing events, and other objects that vary in brightness.
And in the midst of all their hard work, they also sometimes just get lucky. Last year, on Oct 30, a 12th magnitude (bright enough to see through off-the-shelf telescopes), jumped to 7th magnitude (something easy to see through binoculars). The Halloween date, as Joe tells it, made him thing it was a practical joke, but (as he tells it laughing) the fact that a Japanese fellow (not a high candidate for Halloween pranks) was on the announcement, made him think it was real. So, he got a satellite observation with Swift to see if it was a CV – nope, it wasn’t. Some colleagues dove through historical plates. No history of misbehavior. Spectra were taken and compared to pre-brightening spectra – It looked like an A star across the boards. It also had a completely symmetric shape in its brightening and fading. All these bits added up to this star, Var Cas 06, was a microlense. These are obscenely rare events. I think he just said you’d have to watch 10^12 stars for an entire year to see one of these events. And this one was a nearby field star that brightened to binocular viewing brightness. That makes this a very insanely improbable event.
Thanks to automated surveys, lucky observations, hard work, this 40 day microlense event was masterfully and rapidly understood.
Andy Gould told Joe a neat story about how the idea of gravitational mcirolensing came from Einstein. He’d figured out the theory 3 years before he published his first relativity paper, but he didn’t publish his work because he thought it was an unobservable effect. The thing is an engineer in Hungary somehow found out about it and became a terrible pest. That engineer (a rather famous fellow named Mandel) ended up going to America, than came back and pestered Einstein some more until it was finally published in Science. BUT, Einstein attached a note saying it was a useless piece.
That work rested ignored until the 90s. Today microlensing is a cottage industry.
One final fascinating fact: Joe just told us that an early calculation by a name I didn’t catch said that one of these nearby stars may go Lense! every 30 years. The Japanese amateur comet hunter who found Var Cas 06 had been sweeping the sky for new objects for 29 variables. Now that is statistics at work.
Now, time for bed…