Go stargazing from orbit!

I was watching the video of the European Space Agency’s fifth and final ATV cargo ship, Georges Lemaitre, departing from the International Space Station, when I became curious as to the stars visible in the sky.

Starry sky
An enhanced view of the ATV-5’s departure from the ISS reveals the stars. Image credit: ESA/NASA

It turned out that two bright planets were visible in the video, along with asterisms, or star patterns, from a number of constellations, plus what is probably the most famous star cluster in the heavens.

To do my stargazing from orbit, I first had to think a little of the geometry of the view. The ISS is zipping around the Earth from west to east, so it is clear from watching the video that the stars sinking in the sky behind it are roughly in the west.

Then I spotted that the two brightest “stars”, which sink low towards the horizon early in the clip, are actually those planets. Venus is brighter, and the lower right of the two, with Mars appearing close to it (just a line-of-sight effect, of course). Watch, by the way, as Venus continues to shine brightly through the band that is the Earth’s thin atmosphere.

From the positions of the planets, I was able to get a scale and orientation of the sky view which I could compare to a view for the same night in a planetarium-type program on my computer. This helped pick out brighter stars in constellations Cetus, Pisces and Pegasus.

Venus and Mars
Venus and Mars sink towards the Earth’s horizon. Image credit: ESA/NASA

Then, as the ISS sped on, and the ATV-5 spacecraft receded further from the space station, it could be seen to be sitting neatly inside what is known as the Square of Pegasus, tipped onto one corner, like a diamond. The square is actually completed by a star in another constellation, Andromeda, which shows at the top of the diamond.

In the same shot, it is possible to see a pattern of three stars, near the top centre of the field of view, which are the familiar main stars of the zodiacal constellation Aries.

Great Square of Pegasus
The Great Square of Pegasus can be seen wrapped around the receding ATV-5. Image credit: ESA/NASA

Then, as the video continues, more stars descend into view. I was able to recognise some of those that mark the line of Andromeda, stretching from the star that it “shares” with the Great Square of Pegasus (α Andromedae).

The famous Andromeda Galaxy, M31, would be a little to the right of the uppermost star shown, β, but is too faint to be seen.

But an added delight, appearing at top centre towards the video’s conclusion is that famous star cluster, the Pleiades, in the constellation of Taurus.You can just make out its familiar pattern.

I enhanced some of the screen grabs I made from the video, using Photoshop Elements. Why not go stargazing from orbit yourselves by checking out some of the other videos taken from the ISS when it is on the night side of the Earth?

Andromeda and the Pleiades
Andromeda and the Pleiades in Taurus are now visible. Image credit: ESA/NASA
Paul Sutherland

Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.
Paul Sutherland

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Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.

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