06-25-2019, 04:46 PM
"An asteroid would have little movement across the background of stars when it’s headed straight toward us, right?"
Good question. Even if the asteroid were heading straight towards Hawaii, the rotation of the earth would provide quite a large baseline for something close to Earth, so you would see it move with respect to the background stars. I don't know exactly how ATLAS and Pan-STARRS schedule their observations but would be very surprised if they look at the same piece of sky at the same time every night for this very reason.
Good question. Even if the asteroid were heading straight towards Hawaii, the rotation of the earth would provide quite a large baseline for something close to Earth, so you would see it move with respect to the background stars. I don't know exactly how ATLAS and Pan-STARRS schedule their observations but would be very surprised if they look at the same piece of sky at the same time every night for this very reason.