Got it! Gaia Observatory Snaps Photo of James Webb Space Telescope at L2:
Both spacecraft are located in orbits around the Lagrange point 2 (L2), 1.5 million km from Earth in the direction away from the Sun. Gaia arrived there in 2014, and Webb in January 2022.
[...] A few weeks before Webb's arrival at L2, Gaia experts Uli Bastian of Heidelberg University (Germany) and Francois Mignard of Nice Observatory (France) realized that during Gaia's continuous scanning of the entire sky, its new neighbor at L2 should occasionally cross Gaia's fields of view.
Gaia is not designed to take real pictures of celestial objects. Instead, it collects very precise measurements of their positions, motions, distances, and colors. However, one part of the instruments on board takes a sort of sky images. It is the 'finder scope' of Gaia, also called the sky mapper.
[...] After Webb had reached its destination at L2, the Gaia scientists calculated when the first opportunity would arise for Gaia to spot Webb, which turned out to be 18 February 2022.
After Gaia's two telescopes had scanned the part of the sky where Webb would be visible, the raw data was downloaded to Earth. In the morning after, Francois sent an email to all people involved. The enthusiastic subject line of the email was "JWST: Got it!!"
The astronomers had to wait a few more days for Juanma Martin-Fleitas, ESA's Gaia calibration engineer, to identify Webb in the sky mapper images. "I've identified our target" was the message sent by him, with the images attached and the two tiny specks labelled as 'Webb candidates'.
After scrutinizing these carefully, Uli replied: "Your 'candidates' can be safely renamed 'Webb'."
(Score: 4, Funny) by Anonymous Coward on Tuesday March 29 2022, @03:45AM (7 children)
Here is a close-up of the image:
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(Score: 1, Funny) by Anonymous Coward on Tuesday March 29 2022, @04:15AM (6 children)
Well, let's hope the JWST can get a better photo of an exoplanet.
(Score: 0) by Anonymous Coward on Tuesday March 29 2022, @07:04AM (2 children)
it does take better selfies, wonder if it can point back at gaia, was a bit hsrd to trll from the orbit lines pic if thstvwas possible.
(Score: 0) by Anonymous Coward on Tuesday March 29 2022, @05:46PM
JWST can't point at Earth. That would expose the telescope section to direct sunlight which would overheat and damage it. That's why it has that giant sun shield, so the optics stay cold.
(Score: 2) by Immerman on Tuesday March 29 2022, @05:52PM
I think it might be possible while maintaining normal operating orientation. Obviously Webb could just rotate its heat shield to a sub-optimal angle to get the picture if they had a good enough reason to do so, but there's several reasons why that's a bad idea. But it may well be possible without that.
Both are pseud-orbiting L2, so are, on average, the same distance from the sun (though Webb may actually be slightly closer since that big sun shield doubles as a solar sail, providing a small but constant amount of outward thrust that must be counteracted by being slightly closer, so that it would slowly fall towards Earth without it.
Webb's orbit is (roughly) circular, inclined a bit from perpendicular to the line through the Earth and sun. That keeps it permanently outside the Earth's shadow to avoid thermal fluctuations, with the thermal shield pointed at the sun and protecting it from the heat radiating from both the sun and Earth. Gaia on the other hand has one of those complicated volumetric pseudo-orbits that kind of scribbles on the surface of a cylinder whose axis is perpendicular to the sun.
The big question is what is the maximum angle Gaia forms with Webb and and the sun, and the minimum angle from the sun that Webb is able to target.
I wasn't able to easily find that information, or even detailed orbital characteristics of the two, but there should be a substantial difference in distance from the sun when Webb is at its closest, and Gaia at is furthest. I don't think there's any reason the orbits would be synchronized, so it's just a matter of waiting until both happen at the same time, ideally while they're as close to each other as possible in the plane perpendicular to the sun to maximize the angle they form.
* I'm calling it a pseudo-orbit around L2 because technically it orbits the sun while also getting jostled around by the Earth and the somewhat counter-intuitive complexities of orbital mechanics (unlike the Moon for example, which is actually orbitting the Earth and would continue to do even if an evil wizard banished the sun). But it *looks* like it's orbitting L2 when observed from the non-inertial rotating reference frame of the Earth. I'm not sure if there's a technical term for that.
(Score: 0) by Anonymous Coward on Tuesday March 29 2022, @10:28AM (2 children)
It will, after NASA's graphics artists have done their job.
(Score: 2, Funny) by khallow on Tuesday March 29 2022, @12:11PM
(Score: 0) by Anonymous Coward on Tuesday March 29 2022, @03:21PM
Cringe.