Big Rock Early Warning 2011 AG5

[bigmasterdrago]

This is not an especially close pass, but because of its size and well known orbit, thought I would mention it. Using the Horizons osculating elements for Feb 2, I ran an ephem for the 4.7LD pass 2023-Feb-03 08:51UT. From my location, it is near 15th magnitude fairly high in my SE light polluted sky moving ~1'/min.

The interesting point is that it is much higher and brighter (14.4) on Feb 1 @03:00CST moving thru Sextans and then again high and bright on the Crater/Virgo/Corvus border, next day, same time. This is due to phase angle improvement.

The big rock continues back into Virgo as it dips below my horizon and fades as the phase angle plummets. Then back up in the predawn of close pass on the 3rd but dim. Track below.

   

[PMSchu]

Here's an update for the close approach of (367789) 2011 AG5.

CNEOS predicts that this NEO will make a close approach on 2023-Feb-03 08:51 ± < 00:01 UT at a distance of 0.01215 AU. H=21.9 magnitude, V relative=9.92 km/sec, 'Rarity'=2 & Condition Code=0. This is a medium-sized object, 110 - 250 m.

Using MPC's orbital elements for the epoch 2023 January 16 00:00 UT, ST4v predicts that this NEO will reach a maximum brightness of 14.3 magnitude on February 1 at 2000 EST, 0.01 AU distant traveling through Crater at 49.2"/min. Close approach occurs on 2023 February 3 0400 EST (to the nearest hour) when ST4v predicts that it's 14.9 magnitude moving through Virgo at 65.2"/min. These new elements resulted in a slight change in the time of maximum brightness by 1 hour. 

Here's an Interactive Atlas chart showing the predicted path of this NEO from 2023 January 23-February 3 for Columbus, Ohio:     

This NEO should be easily visible from both the northern & southern hemispheres, weather permitting.

Good hunting,

Phil S.

[bigmasterdrago]

Concerning the February 1 pass, I've got it logged to attempt. Although it is on the fringe of my limit, I may indeed try it due to the rock moving out of my southern light domes. It does not alter its magnitude (slight brightening) as it begins the motion into darker skies. It does lose just a bit of altitude, dropping from 52° down to ~30° at the approach of astronomical twilight. Its continuous proper motion during that time span remains ~35"/min. Distance is ~6.4LD.