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Astronomy Rewind: Keeping Our Data Alive

When I was growing up, there was a small outbuilding between my house and the stand of woods behind our property. The previous owner had built it as a little house in its own right, everything on a miniature scale, so that while it looked like an actual house — with front door, nice windows, even a porch and small deck on the back — it was comprised of only one room inside. This man’s kids had used it as a playhouse, but when I got my hands on it, I turned it into what a young boy thought of as his ‘lab,’ with microscope, chemistry set and telescope.

On the walls I put photographs I had bought at Chicago’s Adler Planetarium, and I can still see those blurry images of Saturn, Jupiter and the Milky Way, all taken at the Palomar Observatory, and almost as breathtaking for what they didn’t reveal as what they did. I gradually augmented these photos with sky charts and other imagery, and would use these to plan my observing sessions with the 3-inch reflector I would take out into the yard.


Image: A classic photo (though not one of my Palomar images). This is M31, then known as the Great Andromeda Nebula, its nature as a separate galaxy not being known when the photograph was taken in 1888 by Sir Isaac Roberts. Reproduced in A Selection of Photographs of Stars, Star-clusters and Nebulae, Volume II (The Universal Press, London, 1899), this is the image whose long exposure time first.revealed M31’s spiral structure. Photos like these may look quaint compared to the brilliant detail and color of today’s work, but studying the sky over long periods of time may tease out new information, making even our older datasets useful tools for exploration. Credit: Isaac Roberts.

You would think old astronomical photographs would have a place only in memories like these, but I’m reminded of the vigorous debate that broke out not long ago over the anomalous star KIC 8462852, and Bradley Schaefer’s contention that, on the basis of archival imagery, it could be shown to have undergone a long-term dimming (see KIC 8462852: A Century Long Fade? for more on this — there are likewise numerous articles in the archive).

Schaefer was using a collection of some 500,000 sky photographs in the archives of Harvard College Observatory, covering the period from 1890 to 1989. A program called Digital Access to a Sky Century@Harvard (DASCH) has been digitizing the observatory’s archives, offering a way for astronomers to re-examine historical imagery. DASCH has only digitized a fraction of the archives but it’s a work in progress. What else can we do to reinvigorate such material?

One answer is a project called Astronomy Rewind, whose aim is to restore tens of thousands of astronomical images — photographs, radio maps and other sky-related material — from a wide variety of sources, placing them into context in digital sky atlases and catalogs. The project is part of the Zooniverse platform that gave us Galaxy Zoo a decade ago and now includes ‘citizen science’ projects in a variety of disciplines. Here the idea is to turn our attention to the contents of scientific journals and collate their imagery over time.

American Astronomical Society journals go back to the 19th Century and became accessible electronically in the 1990s. The volunteers will catalog the types of images, separating photographs with and without sky coordinates, maps of planets with or without latitude and longitude grids, graphs and diagrams, focusing on labeled images or those with sufficient detail to make a clear determination of orientation and sky position. Other images will be sent to Astrometry.net, which identifies areas of sky by comparing photos to star catalogs.

The project depends upon human judgement and pattern recognition at a large scale:

“You simply couldn’t do a project like this in any reasonable amount of time without ‘crowdsourcing,’” says Julie Steffen, AAS Director of Publishing. “Astronomy Rewind will breathe new life into old journal articles and put long-lost images of the night sky back into circulation, and that’s exciting. But what’s more exciting is what happens when a volunteer on Zooniverse looks at one of our journal pages and goes, ‘Hmm, that’s odd!’ That’ll be the first step toward learning something new about the universe.”


Image: An early view of Orion. This is a digital print of a photographic plate from the Ritchey 60-inch telescope at Mount Wilson Observatory, made in 1908. Credit: Mt. Wilson Observatory.

The journals involved at present are The Astronomical Journal, Astrophysical Journal, Astrophysical Journal Letters and the ApJ Supplement Series. Images are to be annotated and extracted into digital files that will end up in data repositories as well as becoming part of the Astronomy Image Explorer and becoming viewable in the data visualization tool and sky atlas WorldWide Telescope.

Once up to speed, Astronomy Rewind hopes to process 1,000 journal pages daily, with each page examined by at least five different people to produce consensus. This number is based upon other projects at Zooniverse, where 1.6 million volunteers have classified 4 billion images over the last ten years. Peer-reviewed publications, over 100 of them, have flowed from the Zooniverse work, and as the KIC 8462852 story shows, the potential for discovery is here.

We have to remember as we look into old astronomical materials that we continue to accumulate data at a faster and faster rate. We’re learning how to sift through older material as we build the database from which details that may have escaped our attention decades ago can come to light, perhaps to be reinterpreted in the context of subsequent findings. An earlier effort, the ADS All-Sky Survey, was originally set up to analyze imagery from old astronomy papers, but using computers for the job wasn’t always effective. Now we turn volunteer eyes on the cosmos as we bring digital technologies and older printed journals together.


Comments on this entry are closed.

  • Larry Kennedy March 24, 2017, 11:52

    These programs are doing very important work. What a shame if hard won data should fade away into the background due to being almost inaccessible in the evolving world.

  • Alexander Tolley March 24, 2017, 17:46

    IAnd not just astronomy. There is a wealth of data that backs up journal papers in the sciences that have never been accessible but should be. Then consider the wealth of physical objects in museum archives, e.g. the British Natural history Museum’s huge collection of specimens from around the world of fauna, both contemporary and paleo. Just recently I read a paper on the analysis of pollen grains on specimens of bees in a collection that was used to analyze habitats and flowers that the bees visited in the past compared to the impoverished contemporary situation.

    The digitization and archiving of the world’s artifacts and physical data will prove a treasure for future research in a number of disciples, some we cannot even guess at.

    • J. Jason Wentworth March 26, 2017, 23:23

      This is very–and sadly–true. Dr. Rupert Sheldrake, a British biologist who theorizes that the laws of nature are not rigidly fixed, but are more like habits which become more and more ingrained through repetition over time, endeavored to look up past measurements of the speed of light and the gravitational constant “Big G” in old volumes of the physics handbooks, in order to see if there were any slight changes in their measured values (and there were). But he was almost unable to do so, for lack of old volumes of the handbooks:

      As he described *here* http://www.youtube.com/channel/UCz8XNwQXIAejAaDmEaPNmIA/featured (beginning at 9:53 in his 18:19 talk at TEDx Whitechapel), he had great difficulty locating the old physics handbooks that contained the information he sought; it turned out that the Patent Office Library in London had the *only* copies of the old volumes that he was able to find! Since scientific work not uncommonly requires comparing measurements or observations made years or even decades apart, it’s troubling to think about what other opportunities for discoveries may have been lost by trashing old journals and books without digitizing them for researchers to use. Also:

      Physical artifacts (especially biological ones in collections, as you mentioned) are indeed ephemeral, and 3-D scans or images of them could permit future researchers to have access to–and in a searchable way!–such specimens.

  • xcalibur March 25, 2017, 21:52

    The more digitizing, the better. Of course, physical records are still important, but digitization greatly increases accessibility and redundancy.

  • J. Jason Wentworth March 26, 2017, 1:17

    A big “Amen” to this article! Modern digital scans and analyses of 1910 Halley’s Comet photographs were used to tease out data that were valuable–especially compared with 1986 astronomical photographs and images taken by the “Halley Armada” probes–to determine (or determine more precisely) parameters such as the nucleus’ rate of gas and dust loss when it is active near the Sun. Also:

    Old astronomical photographs are very useful for more accurately determining the orbits of objects (and for charting changes in their orbits over time), by finding them (when they were still undiscovered) on old photographic plates. To give a relatively recent example, Chiron (the first of the centaurs, or “ice-teroids”), which Charles Kowal discovered in 1977, was later also found on a plate taken in 1969, and even on one taken as far back as 1895.

    Pluto was also found on pre-discovery (called “precovery”) plates, as have numerous asteroids, comets, natural satellites, and stars, and Galileo saw Neptune–and even noted that this “star” had moved between two observations!–when he was making discoveries night after night with his little “optik tube.” In addition:

    Even drawings (that is how Galileo’s observations of Neptune were recorded) and written descriptions in notebooks are useful astronomical data that deserve to be preserved. For example, over his long life Patrick Moore made many time-and-date-indexed drawings of the development of dust storms on Mars, changes in Jupiter’s cloud belts and zones, Venus’ polar “hoods” and ashen light, Mercury’s disc features, and lunar features (and changes in them), from which useful data (even such parameters as the wind velocities on Mars) can be extracted. Countless other amateur and professional astronomers’ drawings and written notes also constitute data that should be preserved.

  • Michael Spencer March 26, 2017, 7:14

    Digitization’s chief advantage, aside from shining a light on old data, is search ability, of course; the flip side being the evaporative nature of electronic storage. The originals are to be revered, not let to waste away simply because these flimsy ‘copies’ remain.

    As they say, if you want to keep data for a millennia carve the face of a rock.

    • xcalibur March 26, 2017, 22:31

      I touched on this point in my post. While digitization is an excellent form of progress, it should not completely replace older media. Data rot is a significant concern for electronic storage, as is the often transient nature of formats and operating systems. Ideally, we should maintain hard copies of important data, alongside digital versions for greater access and redundancy.

  • ljk March 27, 2017, 13:27


    Where telescopes cannot (yet) see – the Moon as seen by Scriven Bolton, Etienne Trouvelot, Lucien Rudaux, Chesley Bonestell

    Angelo Adamo

    (Submitted on 15 Mar 2017)

    Scientific illustrations, thanks to the vision of great artists fascinated by astronomical research and astronautics, have provided us with an accurate depiction of the possible views which mankind will one day observed from locations other than our planet. In this talk I will pay homage to some of these geniuses who serve science, and underline the scientific, artistic, political, and social implications deriving from a wise use of space-art.

    Comments: 9 pages, 4 figures, published in the proceedings of SEAC 2015 Conference (Rome)

    Subjects: History and Philosophy of Physics (physics.hist-ph); Earth and Planetary Astrophysics (astro-ph.EP)

    Journal reference: Mediterranean Archaeology and Archaeometry, Vol. 16, No 4, (2016), pp. 509-517

    Cite as: arXiv:1703.08138 [physics.hist-ph]
    (or arXiv:1703.08138v1 [physics.hist-ph] for this version)

    Submission history

    From: Angelo Adamo [view email]

    [v1] Wed, 15 Mar 2017 11:03:46 GMT (887kb)


  • Alyssa Goodman March 27, 2017, 16:02

    Thanks to you all! I am Prof. Alyssa Goodman, founder of the ADS All Sky Survey & scientist on the Astronomy Rewind project. I am extremely grateful for everyone’s enthusiasm. Here’s the text of my (Public) facebook post, thanking the many others who’ve made this happen & offering some demo & video links that might interest you all…

    My colleagues and I are honored that Nature has decided that our “Astronomy Rewind” Zooniverse/AAS/Seamless Astronomy citizen project is “News.” Actually, I think it’s more like “Olds.” (After all, we are putting old images back on the Sky!) Yes, Bryan Gaensler, they’re zombies, I know.
    (Press release at: https://aas.org/media/press-releases/astronomy-rewind; live WWT sample at http://tinyurl.com/astrorewindsample; quickie video demo at
    Many thanks again to Alberto Pepe Gentile, Alberto Accomazzi, Julie Steffen, Pat Udomprasert, Erin Pousson Johnson, Curtis Wong, Jonathan Fay, Tony Hey, Laura Trouille, Chris Lintott, Chris Beaumont, Sarah Block, Rick Fienberg, Megan Watzke, Peter Edmonds, and many others not on fb with me who made this happen!)