Friday, November 26, 2010

webspotting 18 - JDSO

As published in the Dec 2010/Jan 2011 issue of SCOPE, the newsletter of the RASC Toronto Centre. Republished here with permission.


If you know me, you know that I love observing double stars. While I have log entries on double or multiple stars as far back as 2000, it wasn’t until 2006 that I started to regularly observe them and include them in my star party itinerary.

Doubles feature in the wonderful The Evening Sky Map by Kym Thalassoudis, which of course categorises objects visible by eye, binoculars, and telescope. Many multi-star targets are noted in Turn Left at Orion. The web site of the Belmont Society of North Carolina had some interesting information, little colour sketches, useful lists but, some time late 2006, it… vanished. I stumbled across the "attractive" summer and winter double lists at the Sky and Telescope web site (typos and all). I repurposed the lists and began checking off items viewed. In January 2007, I procured  Sissy Haas's famous "spreadsheet" entitled Double Stars for Small Telescopes with over 2000 items. I've since viewed 123 targets with an additional 6 attempts requiring a revisit.

I love the colours, the vibrant and the subtle. I enjoy the widely separated doubles that challenge my naked eye (er, eyes with corrective lenses) one-power resolution; I revel at trying to split extremely tight doubles in powerful light buckets under good seeing. It was in May 2009 that I started using a calibrated eyepiece, excited at the prospect of measuring binaries. In addition to seeing fast-movers change over a season or two, I could collect data points for next couple of decades, for long-period partners, making scientific contributions from the backyard. 

I stepped up my research, reading both Observing and Measuring Visual Double Stars and Double and Multiple Stars and How to Observe Them. I rigorously studied the articles by Alan Alder, Ron Tanguay, and Tom Teague, scouring back issues of Sky and Telescope (tucked away at the CAO library). I practiced, relearned basic trigonometry, built custom spreadsheets. I actually connected with Teague to double-check my calculations. I built upon his improved techniques to further streamline the process of visually measuring separation and position angle. The most recent addition to my personal collection is the beautiful Cambridge Double Star Atlas (with its own list of 2000 systems).

While scanning the old Sky and Telescope magazines, I found Luis Argüelles's February 2000 contribution, "The Spirit of 33." The concept was intriguing: offer a forum, online of course using the internet and web, to allow observers to work through target lists and submit their findings. But, it seemed, that in the 9 or 10 years before my discovery of this article, things had tapered off. The "s33" YahooGroup ( was pretty quiet. I was a little disappointed, as I was just getting my legs in double star observing and measurement, and now there did not seem to be an active community of observers.

Happily, I have since learned of the Journal of Double Star Observations at hosted at the University of South Alabama. This is actually a regularly published electronic newsletter with contributions by amateur astronomers. Periodic posts on the binary-stars-uncensored YahooGroup ( I was happy to see some familiar names like "Uncle Rod" Mollise and Mr. Teague and our own Ed Hitchcock. There's a plethora of current articles as well as archives going back a few years. I'm particularly interested in tackling some of the "neglected" items suggested.

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