In a few days, the Astronomical Society of Japan will hold its annual meeting, starting Sep 9:
www.asj.or.jp/en/activities/nenkai/info/
Ordinarily, this might fall below one’s radar, including mine… except:
Terai, T. Yoshikawa, E Yoshikawa, M. Emergency by the Subaru Telescope on asteroid 2024 YR4, which has been pointed out as a possible Earth collision observation PDL01
The NEO (Near-Earth Object) 2024 YR4 was first detected and recognized by the ATLAS telescope network– not a large, costly glass system. This was enough to establish a crude orbit; further tracking put more decimal places on that orbit determination. However, YR4’s trajectory had it recede from Earth, just as we were finding it interesting. As it got farther and farther, it got dimmer and dimmer from our point of view. In order to extend the observation arc, and thus nail down its orbit into the future, we would need larger and larger apertures to keep the target in view.
Enter the Subaru telescope– over eight meters in aperture, and located atop Maunakea in Hawaii: arguably the best skies for astronomy on this planet. The odds of an Earth impact were never high; precision tracking then further reduced and eventually eliminated that risk.
(I repeat: these are independent and academic telescope assets. Let it never be said “NASA is hiding the killer asteroid! NASA is hiding the killer asteroid!” or other such conspiracy lunacy. While ATLAS is funded by NASA grants, operations are all performed by the University of Hawaii. And should ATLAS have missed detecting YR4, it would have been caught by Catalina– University of Arizona-run- or La Sagra or Purple Mountain or someone else.)
Asteroid tracking is not some mystical art, with secret practitioners. Orbit determination is over 200 years old, carried out routinely; at least two centers (Harvard/Smithsonian MPC and Europe/University of Pisa) wrangle and publish current asteroid orbits, even before the determination of “hazardous” or “non-hazardous”. They do this so others- like Subaru, like plenty of others- can follow up on various, published asteroids as they see fit. And now it’s published for all the world: Subaru did.