A Pi’s eye view of the solar eclipse

Last Friday morning I got up at an unfamiliar hour to board a train to Leicester, where BBC Stargazing were broadcasting a special live show to coincide with the partial solar eclipse over the UK. Regular readers will have seen Dave Akerman write here last week of his plans to launch two Model A+ Pis with Pi in the Sky telemetry boards on a weather balloon as part of the BBC’s event, with the aim of capturing stills and video of the eclipse from high above the clouds. As we’ll see, Dave was far from the only person using Raspberry Pis to observe the eclipse; to begin with, though, here’s a downward-facing view from one of his Pis of the launch, done with the help of a group of school students:

I caught up with Dave a bit later in the morning, by which point the payload had been recovered after a shortish flight.

Dave, John and Helen

Dave explains to my three-year-old son that the balloon payload has come down in fields by Leighton Buzzard

BBC Radio Leicester interviewed Dave, making for a really interesting five-minute introduction to what a balloon mission involves. BBC Television filmed several interviews, too, including this one, broadcast on BBC Stargazing live the same evening, featuring images of the eclipse captured by the Pis:

My favourite moment is when the balloon bursts, having reached a diameter of about eight metres. Despite the lack of air, as Dave points out, the pop is clearly audible:

Dave later posted this image of the eclipse captured by one of the Pis:

Solar eclipse, captured by high-altitude Pi

If you watched right to the end of the BBC Stargazing interview, you’ll have heard Lucie Green mention another project, this one with the involvement of BBC Weather’s Peter Gibbs. The Department of Meteorology at the University of Reading is running a citizen science programme, the National Eclipse Weather Experiment (NEWEx), to collect data to study small weather changes expected to accompany an eclipse, such as a drop in temperature and changes to clouds and wind. They particularly encouraged schools to join in, and we sent one of our weather station prototypes to the National STEM Centre in York so that they could help a local primary school take part. They installed it on their roof:

Weather station prototype on National STEM Centre roof

Matt Holmes from the STEM Centre displayed data from the weather station alongside a webcam image of the eclipse:

If you’re in the UK and you’d like to watch the (very) brief interview with Peter Gibbs that followed the one with Dave Akerman, you can catch it on BBC iPlayer, starting at 29m40s.

Other people were using Raspberry Pis to take weather measurements during the eclipse too. Cookstown High School in Northern Ireland have set up another of our weather station prototypes; you can see live data from it at www.piview.org.uk/weather/, which you can drag to see older data and zoom for more detail. School staff are also tweeting more photos and information about the weather station as @STEAM4schools. Here are its temperature recordings during the eclipse:

PiView Weather Station - 20 March 2015, morning

As you can see, it’s difficult to separate out effects of the eclipse from other temperature variation, which is where NEWEx’s big-data approach will hopefully prove valuable.

One computing teacher planned his Friday morning class’s eclipse observations in our forums, with help from forum regular Dougie, whose own measurements are here, and others. They held an eclipse party before school, and they and others have shared their measurements in the forum.

School eclipse party


We’ve seen a number of timelapse films of the eclipse captured using Pis, too. Berlin Raspberry Jam organiser James Mitchell used a Raspberry Pi to make a timelapse of the 74% eclipse seen there:

It’s really great to see Raspberry Pis used in such a variety of ways to enhance people’s experiences of a rare and remarkable astronomical event, and particularly to see the involvement of so many schools. Did you use a Raspberry Pi for observations during Friday’s solar eclipse? Tell us in the comments!


Dougie avatar

I’m famous. My Raspberry Pi with a BMP180 temp/pressure sensor is famous.

Jim Manley avatar

More like infamous, as in, “When Dougie collected data with a Pi is a day that will live in infamy.” ;)

For the record, we collected non-eclipse weather data for the all-too-often unsung “control sample” that makes the differences in the experimental samples noticeable in the first place :D

Andrew Pattison avatar

Great radio interview. I think some BBC TV producers need to be reminded what a “factual reference” is. I know if I was watching those bits on TV and I didn’t know what computer it used I would have loved Dave to be able to tell me! Still, some fantastic coverage and some great images – nice work!

Dave Akerman avatar

Yeah, the radio thing was much nicer. With live TV I felt they wanted me to shut up; with the radio they wanted me to keep talking :-). Also the questions made it easy for me to explain how it works. Finally, no problem mentioning the Pi!


Philip Ashworth avatar

I was in the Faroe Islands with a raspberry pi taking video of the eclipse (while trying to keep it working in the rain). We managed to see totality and so did the pi.

Helen Lynn avatar

Do share the video if you can – we’d love to see that!

Philip Ashworth avatar


I need to edit it. I started it running at 7.30am and mostly left it alone as all I had to look at was a 5″ adafruit bare screen and it was raining quite hard. The file is 1.1Gb but I will try and find some time to edity it down and get the best bits. Unfortunately it was running at 90fps as I had been playing with the script with my 10 year old the day before, so the resolutions is not great. I will send a link to a totality image which I have already grabbed from the video assuming I can work out how to do that,

paddyg avatar

Helen, I’m logging output from my roof-top PVs using (one of) my RPi. Here’s the data for last Friday.


From the size of the bite out of the graph I would estimate that the eclipse reduced my Feed In Tarrif income by £0.04 – a bargain. (Though if the sunny weather later in the morning was as a result…)

Helen Lynn avatar

Thanks for sharing this – really quite a smooth, symmetrical bite.

Helen Lynn avatar

I somehow missed another Raspberry Pi HAB launch, by the University of Southampton Spaceflight Society. They got some great shots from a Pi camera with a Mylar filter: http://susf.co.uk/launches/eclipse/

Geof Lynn avatar

Hi Helen,
Lovely to see John, Yourself and the Pi on telly. Well done all of you!

Chris avatar

My Pi constantly monitors the weather with PyWWS, so I have some for the eclipse (somewhat unintentionally). It uploads the data here: http://wow.metoffice.gov.uk/graphdata?requestedAction=REQUEST&siteID=529146002

There appears to be a small dip in temperature during the eclipse followed by a big increase as the clouds cleared when the eclipse ended. Nothing showing for wind, although admittedly my weather station isn’t sited very well.

Peter Müller avatar

Here is my timelapse of the solar eclipse.
Not very spectacular, only greyscale but crisp clear.
I’m working on a 2nd hopfully better movie.
There is a picture of my nice “Sun watching” setup, too.
Peter from Bavaria

sv1Anonymous avatar

“Despite the lack of air, as Dave points out, the pop is clearly audible”

Most probably the sound has propagated via the strings. Also, I think that what is heard on the video is caused by the vibration of the payload after the ballon explosion and not so much by the ballon itself.

Dave Akerman avatar

Just got round to doing a blog post about my flight – http://www.daveakerman.com/?p=1767

Spencer Organ avatar

My year 8 class setup a Pi pointing out the classroom window to record the sky getting darker.

Unfortunately my lab faced away from the sun so we only got shots of the sky getting darker.

We took a photo every 2 minutes with a nice bit of Python time-lapse code.


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