Fripon means “rascal” in French and is the acronym chosen for the French Fireball Recovery and InterPlanetary Observation Network. The Fripon all-sky camera network aims to track meteorites as they fall over France and to coordinate their recovery as quickly as possible for scientific study. As you might guess, recovering a meteorite quickly is the best way of preserving its original chemistry and mineralogy. Matching that information with the object’s original orbit (calculated from the camera observations) should allow scientists to piece together much more about the asteroid belt and the assorted fragments arriving on Earth from there.
In theory, about ten meteorites should land in France every year but history records that only about 1% are recovered and that, surprisingly, the recovery rate may be decreasing. In an attempt to push the recovery rate up to 20% or better, the Fripon network was launched by five collaborating faculties of four French institutions - the Observatoire de Paris, the Muséum National d’Histoire Naturelle in Paris, the Geosciences department of the Université Paris Sud, and the Geosciences and the Astrophysics departments of the Université d’Aix Marseille.
A glance at the map of the Fripon network showed lots of cameras in France but also the odd one in Italy, Spain, Austria and even Brazil, so I wondered - why not the UK? It seemed like something that I could help with. As background, I’d been fascinated with fireball recovery since I was a kid. After a fireball in Britain on 17 March 2016 fireball got widespread media coverage, I asked Google “why isn’t there a fireball network in the UK?” and so found my way to the UKMON and Nemetode networks which I joined in May (this article has been written for both UKMON and Nemetode). When Fripon launched in June, I decided to join that as well.
I must have been one of the first to try, because I know that other who’ve tried since have been asked to wait a while. However, I was kindly introduced by the director of Fripon to the camera assembly manufacturer (Shelyak instruments of Grenoble) who built and sold me the 171st Fripon camera – pictured here newly unpacked on arrival in London in September.
I thought that camera 171 was operating in splendid isolation, but soon discovered that there was another one already running in Devon, forming the beginning of a UK network. The Italian “Prisma” meteor network provides a good model – it uses the same Basler camera and shares data with Fripon, but is organised from Turin rather than Paris.
The camera itself is a Basler Ace 1300-gm30 digital industrial CCTV camera which uses the GigE protocol, and so plugs into an Ethernet port. It uses Power over Internet and so has just a single cable which can be up to 100 metres long – quite an improvement over the 10 metre maximum that analogue cameras require. The lens is a Focusafe FS12520FEMP with a 1.25mm focal length, F/2 aperture and field coverage of 185°. Shelyak makes the enclosure which is designed to dissipate excess heat. Their experiments showed that the internal temperature is typically eight degrees Celsius above the outside temperature, so in theory there’s no need for a separate heater or fan though occasionally some of the mountain-based French cameras do ice up. The Basler camera has higher resolution than the Watec cameras usually used for meteor detection (1280 x 960 pixels for the Basler, against 720 x 576 for the Watec) which helps deal with the larger area of sky captured by the fisheye lens. Basler doesn’t publish ISO or lux sensitivity data for their cameras, but to capture bright stars I discovered that I needed to run it at an unfeasible two frames per second (compared with 25 fps for the Watec), so it’s significantly less sensitive than the Watec, particularly when running at FRIPON’s normal rate of 29.95 fps. While this makes it perfect for capturing bright fireball events that are likely to drop meteorites, it’s not ideal for traditional meteor astronomy. It’s also not totally clear how the calibration works, given the lack of sensitivity.
The Basler camera’s exposure time can be adjusted very widely while it’s running, meaning that it’s suitable for daytime operation. Because meteorites are bright and can arrive any time of day or night, having the Fripon network running all day is their eventual aim.
Here’s a photo of the Fripon camera installed on my (now fire-free) chimney, with uninterrupted views of East Barnet and the English sky.
While the camera hardware is easy to set up and use, the dedicated FRIPON software is much less so. “FreeTure” is open-sourced meteor capture software written specifically for the project and is freely available on the GitHub repository. Designed for Linux (specifically, Debian) it’s also available in a Windows version.
At the moment, the only screen output is as below – just a brief report on each frame showing the exposure time and the current frame rate, scrolling at about 100 lines of text per second. During a capture the scrolling pauses briefly while results are written, then resumes. The program can also produce an AVI video of the capture. Each frame of the capture is saved as a highly-processed FITS image file and a variety of other summary images and text files are written.
All of the French Fripon cameras are connected and controlled via a Virtual Private Network (VPN).
What next for Fripon Camera 171 of East Barnet? It’s been running every night with FreeTure for six months now, and I’ll keep operating it that way as the software improves and as a UK network of similar cameras comes together, including the one that I’m sending up to Manchester. Meanwhile, I’ll work with Fripon and with relevant UK institutions to see whether the network can be extended to the UK and how best to use the efforts of amateurs like us in the hunt for those valuable bits of scientific data falling from the French and British skies.
(September 2018 update: The UK-based SCAMP cameras are now fully-integrated with the FRIPON network, running FreeTure on Debian-based NUC computers integrated with the FRIPON VPN.)