S-band Spotlight

Observ-a-thon reveals comet nucleus, holiday asteroid, and more!

(left) Arecibo radar observations reveal details of Comet 46P/Wirtanen, including the first definitive measurements of its size! (right) Additionally, using a bistatic configuration, where Arecibo emitted and the Green Bank telescope in West Virginia received, the team captured detailed radar images of near-Earth asteroid 2003 SD220, a slow rotator first imaged by Arecibo in 2015. Find out more here!

About Us


The Planetary Radar Science group is a department of the Arecibo Observatory, which is an NSF facility operated under cooperative agreement by the University of Central Florida (UCF), Yang Enterprises, Inc. (YEI), and la Universidad Metropolitana (UMET). The Arecibo Observatory Planetary Radar program is fully funded by NASA's Near-Earth Object Observations program.

For more information, follow us on Twitter at and !

Recently Observed Objects


For media inquiries, please contact our communications lead, Ricardo Correa

All observations in 2019 - most recent first

2019 AK3
2018 XV
2019 AR2
2019 AW7 - taken from Minor Planet Center's confirmation page as C00GG11
2019 AX5
2016 AZ8

Past Observations

Upcoming Radar Targets

The following table lists targets with submitted observing proposals, including those from our annual high and medium priority proposals. This table is not comprehensive for targets of opportunity, especially newly discovered asteroids. For possible targets of opportunity and long-term future radar targets, updated daily, see: All asteroids visible today (SNR > 2/day), this month (SNR > 2/day), and in the next five years (SNR > 100/day). Note that these tables inevitably include objects that are currently "lost," often suggested by "1d" in the Type column, which stands for "one apparition with a days-long arc," so observer beware!

Object Dates Expected
H mag Request Optical
Request Optical
Request Optical
2016 AZ8 Jan 02-04 High-res Imaging 21.1 Y Y PHA, NHATS, period unknown
SURVEY NIGHT Jan 09-10 Astrometry All the things!
433 Eros Jan 25-Feb 15 Imaging 10.5 Y 5.27-h period
2013 CW32 Feb 01-02 Imaging 21.9 Y PHA, period unknown
SURVEY NIGHT Feb 07-08 Astrometry All the things!
455176 (1999 VF22) Feb 19-21 Imaging 20.6 Y PHA, period unknown
2015 EG Mar 05-07 Imaging 25.7 Y NHATS, 1.29-h period
88254 (2001 FM129) Mar 13-14 Imaging 17.6 Y PHA, period unknown

Requests for Optical Observations:

Astrometry: optical astrometry is specifically requested for objects with plane-of-sky pointing uncertainties of tens of arcseconds or more. Optical observers are asked to submit astrometry to the Minor Planet Center as soon as possible after observations.

Lightcurves: optical lightcurves and period estimates are specifically requested for objects that will produce high-resolution images (i.e., possible shape models), for targets of IRTF thermal-infrared observations, for candidate binary asteroids, and for potential human-exploration targets. Lightcurve observers are asked to relay period estimates to the radar team to help with the planning of radar observations. During the analysis and modeling process, the radar team may request to use available lightcurve data.

Characterization: optical characterization refers to spectra and colors, which are most important for targets of IRTF thermal observations, for completeness of the strongest radar targets, for candidate binary asteroids, and for potential human-exploration targets. Optical observers are asked to relay probable spectral-class information to the radar team to compare with characteristics suggested by radar.

Quick Links