Skip to main content

Catching up on history

Posted by Matthew Templeton on February 27, 2012 - 10:18am

I set aside a sizable fraction of my time per day for about a week in late January and early February to catch up on some long-term projects, especially on many digitization projects undertaken by volunteers for the AAVSO.  There's been quite a haul of archival data over the past several months, and we're getting close to making it all available to the community via the AID.  Importantly, we've begun implementing our new tracking fields in the AAVSO International Database that cover digitized archival data, providing the user with the identity of the person who digitized the record and the citation or BibCode of the work.  Users of these light curves will not only have the observations themselves, but will also know who digitized them and where the data came from so that they will have access to comparison star information, observing methods, and raw step data.  I'm incredibly grateful to our digitizers for their hard work and patience over the past year and I encourage the research community to take advantage of this great new resource.

As of the morning of February 7, there were 76,748 observations in the AID tagged as being digitized from archival sources, and by the time you read this there will likely be several thousand more.  Many of these consist of observations taken from published tables of variable star observations in sources like the Harvard Annals, Memoirs of the Royal Astronomical Society, and others published around the turn of the 20th Century.  Many of these publications have data from observers whose names are certainly a part of AAVSO lore, like Campbell, Cannon, Pickering, Yendell, Furness, and even Argelander.  These have been either keypunched or scanned and automatically converted to data points by a number of volunteers.  A number of people have worked on this project, some long-time members of the organization, and a few new faces as well.  Kevin Paxson, Bob Stine, Christian Froschlin, Andrew Rupp, Steve McKay, and Alan Plummer have all contributed important data sets.  There are too many neat light curves to highlight, but as an example I can point you toward the wonderful light curve of R Leo that now goes back well over 150 years and is almost unbroken during that time.  We've also had a few volunteers help out with various internal projects, including Ken Mogul, who is helping out with a project to digitize unprocessed paper records from AAVSO observers.

A substantial amount of data was also provided by professionals using archival data for their own purposes, who then provided the scanned data to the AAVSO for inclusion.  As an example, we now have a substantial amount of photoelectric data for bright Cepheids courtesy of Doug Welch (and his many students over the years) who provided MySQL-ready files of all of his digitized light curves late last year.  We're also tagging the huge trove of data digitized by Brian Skiff over the years.  Brian's work was an inspiration for the digitization project that we started in 2010, and we wanted to acknowledge his work that has already been a part of the AID for several years.  There's quite a bit of archival data that Brian provided left to be tagged, so the 76,000+ number above will rise soon.  Yours truly has even gotten into the digitizing act, with my keypunched data from the M31_V1 project and a few selected light curves from the Harvard Annals thrown into the mix.

Other projects are coming up at Headquarters, including my wrapping up two NASA- and NSF-funded research projects before the summer.  Working with the digitized data has been a pleasant way to wind down from the activity surrounding the end of the year and the recent AAS meeting in Austin, Texas, especially since I can take all of the hard work that volunteers did and turn it into real results -- new data sets for the AAVSO data user community.  I'm deeply gratified by the effort that volunteers have made in this project, and I encourage everyone to make frequent use of this new trove of data.  Many light curves of LPVs have been extended backwards in time by several decades at least, and there might be some interesting science there for those willing to go through the data with a careful eye.  It may be challenging to interpret all of the data -- especially with different sequences in use over the years for many stars -- but you'll have a great head start in looking at these objects over the long term now.  Importantly, you'll have a record of the publication that the data are taken from with each record in the light curve in the form of either a citation or an exact ADS BibCode, and you'll be able to go back and investigate things like step magnitudes and sequences to better understand these data.

Before I close, I'd also like to thank HQ staff member Sara Beck for writing such great Java software for HQ use; her software has made it incredibly easy for me to tag all of the data that volunteers have submitted.

There's more work to be done, more sources to be digitized, and more data to be processed, and we'll be adding new data sets to the AID very soon.  In the meantime, enjoy your new light curves, and be sure to thank the observers and the volunteer digitizers when you do!

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484