1. INTRODUCING ASTROTAGS How amateur photographers can make a map of space Photo by orvaratli

2. ASTRONOMY PHOTOGRAPHER OF THE YEAR To mark International Year of Astronomy 2009, the Royal Observatory Greenwich decided to launch Astronomy Photographer of the Year. It was going to be a traditional photo competition, but…

3. DIGITAL OUTREACH ON FLICKR Running the competition on Flickr not only let us reach a dedicated, worldwide community of astrophotographers, but a whole bunch of people who might not know they were interested in astronomy. It also made us ask: What’s the space equivalent of geotagging?

4. THERE WASN’T AN EASY ANSWER… It’s not like putting a pin in a map. Things in space move about and there are the added dimensions of depth and time. The question was, how could we make astrotagging easy for amateurs?

5. ANSWER PART ONE: THE ASTROTAGGING ROBOT Astrometry.net already had a Flickr group with a robot that calculated the astrometry of submitted photos, then added the results as notes and comments. Could it add machine tags too?

6. Photo by Skiwalker79 RESULTS APPEAR AS THREE PART MACHINE TAGS astro:RA=23.3534170222 astro:Dec=30.6174596384 astro:pixelScale=3.50 astro:orientation=-12.78 astro:fieldsize=1.56 x 1.04 degrees astro:name=NGC 598 astro:name=M 33 astro:name=Triangulum galaxy

7. BUT WHAT ABOUT STUFF LIKE PLANETS? We decided that if people took a photo of a planet or comet, they probably meant to, and so knew their subject. So this is the bit that’s done by hand, along with a tag for date and time. astro:gmt=2008-03-22T06:40 astro:subject=saturn Photo by Ethan Allen

8. EXPLAINING IT ALL… Having worked out how to do astrotagging we needed to explain it to our visitors. We wrote illustrated guides called Astrotags explained, and How the astrotagging robot works. We also commissioned a short animated film.

10. WHAT CAN ASTROTAGS DO? Flickr already has a public API, which means astrotags are immediately accessible to anyone who wants to play around with them. At the ROG we’ve made a mashup with Google Sky.

11. ANYTHING ELSE? For non-specialist audiences photos that belong to them and their friends are a huge draw. Robot and hand-made astrotags mean there is the potential to use these photos en-masse to help explain science. Exhibitions Online Planetarium Installations Mobile Photo by giumaiolini

13. AND COULD PHOTOS FROM PROFESSIONAL SCIENCE BE ASTROTAGGED TOO? Machine tags can be used to link blog posts, photos and events together. And Flickr’s Title and Description fields can be called via their API which means astrotags could be an easy way for science centres to harvest the latest imagery using existing infrastructure. Photo by Nik Szymanek

14. AND FINALLY… Using the public’s photos means we have people stories as well as science stories. For us, the result was that Astronomy Photographer of the Year appeared on the Flickr blog twice, across the web, in every UK broadsheet and in several tabloids… …it even made the front page of the Sun online

15. Photo by Pere Sanz