A photo taken at the European Space Agency's Madrid astronomy club revealed an awesome surprise - a photobombing bird flying through a shot of the International Space Station.

Capturing the ISS as it transits across the Sun or Moon is a fun challenge for astrophotographers, both professional and amateur. The station moves across the sky at a rapid clip of around 27,600 kilometres per hour (17,150 miles per hour), seeing a sunrise every 92 minutes.

To photograph it takes being in exactly the right place at exactly the right time with a powerful enough camera, especially if you want to snap it moving across the face of the Sun or Moon, which it takes less than two seconds to do.

So as you can imagine, a photobombing bird at the very same moment? Not the most common of events.

And in this photo, the bird, seen flying vertically from the bottom of the Sun, is flying at just the right height to appear to be the same size as the ISS, which is transiting on a diagonal - which meant that the club could figure out how high up it was.

"The Station flies around Earth at around 400 kilometres [altitude] (250 miles), allowing the astronomy club to calculate that the bird was flying 86 metres (282 feet) from the camera lens," the European Space Agency wrote.

You can see a closer look at the bird silhouette in the crop below:

iss birb photobomb close upESA

Of course, photographing the ISS with the full moon is a lot more challenging, since the Sun is full all the time, but the Moon is full only once a month.

For example, astrophotographer Dylan O'Donnell had to wait 12 months for this stunning shot.

If you want to try your hand at photographing the ISS yourself, NASA has posted a handy guide to photographing the ISS with the Moon on its website.

There's also a website that will help you figure out when the ISS will be overhead. If you want to go really next-level, you can try for a photobombing bat.

But will anything ever beat NASA's photo of the ISS photobombing this year's full solar eclipse?