ESA’s Gaia Just Took a Picture of L2 Neighbor JWST

In February, the Gaia spacecraft took a picture of its new companion in space at the second Lagrangian point.

The motions of more than a thousand million stars are being mapped out by the telescope. When the two satellites were a million km apart, it was spied by the mission.

In the direction away from the Sun, the two spaceships are located in the same area around the L2 point. The two people who have been there since the beginning are Gaia and Webb. The two spaceships aren't quite in the same place. L2 is in a Lissajous circle, with a more oblong shape, while JWST is in a halo circle. L2 is not a fixed point in space, but follows the Earth around the Sun.

Astronomers Uli Bastian and Francois Mignard of Nice Observatory realized a few weeks before the L2 arrival that the new neighbor should occasionally cross Gaia.

The first time they would have the chance to take a picture was February 18, 2022.

Astronomers said that little reflected sunlight came from the new telescope, and that the light appeared to be a tiny speck of light.

Gaia is not designed to take pictures of objects in the sky. It gathers precise measurements of their positions, motions, distances, and colors. One of the instruments uses a type of finder scope as its sky mapper, and the other instrument took the picture of Webb.

Every six hours, the sky mapper scans a narrow strip around the entire sphere. Every few months the entire sky is covered with the strips tilted slightly, so that the data from everything that is bright enough to be seen by the instruments is gathered.

The sky mapper instrument was originally intended for technical servicing and engineering purposes, but during the eight-year mission they have found some scientific uses for it. Why not use it for a picture of him?

After the sky mapper took the picture, the raw data was sent back to Earth, and it took a few days for the astronomer to find and verify the small dot in one photo was indeed JWST.

The email was sent by Francois Mignard with an enthusiastic subject line.

Maybe every spaceship should have a friend to keep an eye on.