Note, Paper: April AJ, yay!

The April issue of Astronomical Journal is not so Solar-System-centric as last month’s, but that’s publishing for you. Last month was a bounty, this one’s a breather:

K. Tang, A. Pomazan, Maigurova, N. et al. Error Analysis for Rotating-drift-scan Charge-coupled … a 147 ad24ff
Chandler, C. O. Trujillo, C. A. Oldroyd, W. J. The Active Asteroids Citizen Science Program: Over… a 156 ad1de2

Active asteroids. Do I need to explain why I bring up active asteroids?

Not so obvious: rotating drift scanning is a method to do deep “search” for astronomical targets, allowing a reasonably-sized telescope to match a bigger one. I put search in quotes, because RDS only works if you know the velocity vector (at least, from your point of view) of the target. Objects in the distant Solar System are easy enough, because their motion is dominated by the motion of us on our moving, known Earth. As one get closer and closer to the Sun, the orbital speed grows, and the relative (Earth vs. target) speeds are large, and in increasingly arbitrary directions. Therefore, RDS is not some magic solution that will find all these objects we want. Kuiper Belt, sure, Centaurs and Jupiter/Mars Trojans, sure to a lesser degree. Inside the Main Belt, the integration time (and therefore sensitivity improvement) is low to negligible for new discoveries. RDS, at least for Mars-crossers and NEOs, helps us for follow-up studies, not search per se.