Photo Shows ISS and China's Tianhe-1 Space Station Module Meeting in Sky

An astronomer has captured an image showing both the International Space Station (ISS) and China's Tianhe-1 space station in the sky at the same time.

Spotting the ISS whizzing overhead is not unusual; it orbits Earth every 90 minutes. According to NASA, the station is the third-brightest object in the sky and can be seen with the naked eye as the sun reflects off of it.

There's even an interactive map to help sky watchers determine when the ISS will fly overhead next so they know when to look up.

But the ISS is not the only habitable station in the sky. In April, China successfully launched the core module of its planned Tianhe-1 space station and placed it into orbit around the Earth.

It may only be one part of the planned station, but the core module is still 54 feet in length and weighs nearly 50,000 lbs, according to Space.com. This means that it, too, may be visible from the ground—though it may not be quite as bright as the ISS.

The ISS, for contrast, is 356 feet end-to-end thanks to the "wingspan" of its solar arrays, according to NASA, and is made up of many different modules which took a total of 42 flights to deliver. It weighs 925,335 pounds.

Both space hubs were captured crossing the sky at the same time on Thursday by astronomer Gianluca Masi, founder of the Virtual Telescope Project based in Italy. The photo can be seen below.

ISS Tianhe-1 spotted
The photo of the ISS and Tianhe-1 station in the sky at the same time. It was taken using a Canon 5DmIV DSLR body and a Canon EF 8-15mm f/4 L USM Fisheye, both on a tripod, according to Masi. www.virtualtelescope.eu Gianluca Masi/Virtual Telescope Project

In a blog post, Masi explained he had researched the opportunity to capture both stations at the same time and discovered he could do so last night, just after sunset.

Masi labeled the paths of both stations as they crossed the relatively bright evening sky, along with star constellations and other celestial objects like Mars and the moon, which can be seen clearly.

The ISS approached from the western horizon first, Masi wrote, adding: "One minute later or so, the Tianhe-1 appeared, too. It was truly amazing to spot both the stations at the same time, really."

The photo was taken in Rome, Italy. Masi said: "I loved the idea to capture the whole sky, framed by the borders of the Circus Maximus and the Palatine Hill."

The astronomer told Newsweek the "meeting" of the two stations in the sky happens "regularly, but not often." Visible passes with just one or the other are far more frequent.

China is in the process of stocking up the Tianhe-1 core module ahead of the planned arrival of Chinese astronauts—called taikonauts—to the station, perhaps as soon as June. A supply launch mission, called Tianzhou 2, has been postponed twice this week.

Three taikonauts are expected to be sent to the Tianhe-1 core module as soon as June 10 as part of the Shenzhou 12 mission, which could last months, according to NASASpaceFlight.

International Space Station
The International Space Station, seen here in this photo dated September 2006. The ISS is not the only habitable station in space. NASA/Getty