Asteroid (90) Antiope occults magnitude 6.7 HIP 112420 (LQ Aquarii)

July 19, 2011

10:20 - 10:25 UT

(click here to return to the 2011 IOTA Annual Meeting page)

Simplified Version of the Information Provided here for new Observers


Watch the Occultation LIVE!!!

Scroll to page bottom for details!


If weather conditions permit (the probability for clear skies is very high), we plan to observe the occultation of  6.7-mag. LQ Aquarii (= SAO 165285 = HIP 112420) by the large binary asteroid (90) Antiope that is predicted to pass over much of northern California Tuesday morning, July 19th. The components of Antiope are each about 90 km in diameter; their centers are about 170 km apart, with a circular orbital period of 16.5 hours. The line joining the centers of the two objects will be about 45° from the direction of motion of Antiope, so one component or the other will occult the star in a path about 200 km wide (taking into account projection on the Earth’s surface). Most stations will have an occultation by one of the objects. For a short distance near the actual central line, either there will be no occultation by either component, or a short occultation by both components; we can’t be sure. By spreading many stations across the total range and the 1-sigma uncertainty zone, we plan to map the profiles of both objects in detail. Path maps and other information about this interesting occultation, and about the IOTA meeting (maps showing Sierra College), are in this 0.5-megabyte Power Point file.


Detailed Information about this event provided by David Dunham (text file)


Message from David Dunham regarding mobile stations this event (text file)



Predicted path of the occultation of LQ Aquarii by (90) Antiope from Steve Preston

(updated 9 June 2011)


Pre-filled Asteroidal Occultation REPORT FORM for this event

Replace "LastName" in the file name with YOUR Last Name!!

Pre-Point Charts for areas near 122 W longitude:  Postscript    PDF   (zip files)

Pre-Point Stars (text list)


Star Catalog Comparison for HIP 112420 for 2011 July 19



Updated Miriade Model of (90) Antiope at 10:25 UT - June 15, 2011

Updated Miriade (IMCCE-Obs de Paris) Model of (90) Antiope at 10:25 UT from Descamps et al., (2009)

Notice possible crater in lower component.


Icarus article showing possible crater on one component



Sky-plane plot of the Antiope system

Sky-plane plot of the Antiope system for the time of the occultation,

with the motion of the asteroid drawn as the long arrow from upper right to lower left. 


Resulting Path (GRAY lines) IF Prediction and star position are correct.

Predictions taking into account possible errors





Miriade model superimposed on predicted path (Roger Venable diagram)




Updated List of Reserved Chords for this Event

(as of July 18, 2011)


With the new star catalog comparison using HIP1 data for the star for the nominal prediction now used on all prediction sites and by Occult Watcher (OW),
The north edge = +108 +15 (HIP2) +46 (1 sigma) = +169 km, round to +175 km.
The south edge = -113 -21 (PPMXL) -46 (1sigma) = -180 km, round to -185 km
According to this plan, you should select sites within +2 and -2 km of the following distances (I indicate the current OW station #'s that already comply with these well enough):

Download complete Station Sort Text File here (includes IMPORTANT notes)


+175 Degenhardt 1 OW#63
+165 Degenhardt 2 OW#62
+155 Degenhardt 3 OW#57
+145 Degenhardt 4 OW#11
+135 Degenhardt 5 OW#55
+125 Degenhardt 6 OW#05
+120 Degenhardt 7 OW#66
+118 Degenhardt 8 OW#70
+112.14 Fleishman
+110 Degenhardt 9 OW#65
+105 Degenhardt 10 OW#10
+100 Degenhardt 11 OW#59
+95 Degenhardt 12 OW#80
+92 Degenhardt 13 OW#77
+88 Degenhardt 14 OW#79
+85 Degenhardt 15 OW#01
+80 Degenhardt 16 OW#60
+75 Degenhardt 17
+70 T. George
+65 Lyzenga OW#18
+60 Preston
+59 Degenhardt 18 OW#64
+55 Garlitz
+52.5 Okasaki 4
+50 Preston
+46.32 Maley 10
+43.4 Okasaki 3
+40.61 Maley 9
+37 Okasaki 2
+33.17 Maley 8
+30.82 Maley 7
+27 Okasaki 1
+23.99 Maley 6 OW#9
+19.90 Maley 5 OW#7
+13.87 Maley 4 OW#6
+10 Wilson
+8.84 Affenita visual
+4.94 Maley 3 OW#4
+1.80 Maley 2
-1 Bredner
-4.36 Maley 1 OW#3
-10 Venable 1
-14.53 IMCCE/SETI station A1
-17.9 Vincent fixed site home
-21 IMCCE/SETI station A2
-24 IMCCE/SETI station A3
-26.85 Swift fixed site home
-31 Sumner
-35 Venable 2
-40 Venable 3
-45 Venable 4
-46.48 Kenyon fixed home
-50.77 Case fixed home
-53.3 Becker
-55.8 Shelton fixed home visual
-58 Venable 5
-62 Venable 6
-66.0 Westfall, Antioch, CA (definite fixed site)
-69 IMCCE/SETI station B1
-72 IMCCE/SETI station B2
-72 Chris, R. Nolthenius' friend, but probably cloudy?
-76 IMCCE/SETI station B3
-79.89 MorganOW#12 home, could be mobile, to -70; home ok, too
-85 Foothill College Obs.
-85.18 MorganOW#13 fixed site
-89.47 MorganOW#14 fixed site
-95.5 Nolthenius
-99 Dunham 1
-102 Oak Ridge Obs.
-104 Beard
-107 IMCCE/SETI station C1
-110 Dunham 2
-114 IMCCE/SETI station C2
-118.08 Schumaker (home)
-120 Dunham 3
-126 IMCCE/SETI station D1
-132.11 Breit OW#17 fixed site, Morgan Hill, CA
-135 IMCCE/SETI station D2
-138 Dunham 4
-142 IMCCE/SETI station D3
-145 Dunham 5
-150 Dunham 6
-155 Dunham 7
-165 Dunham 8
-175 Dunham 9
-185 Dunham 10
-195 Dunham 11

-205 Dunham 12

Note that distances on this map are on the ground, and need to be determined with the google map either in OW, or on D. Breit's site

The OccultWatcher station list, and the sites file on D. Breit's Global web site give
different answers, at least at distances more than about 50 km from the central line.


Post Occultation Discussion via EVO

Tuesday, July 19   1600 PDT   (2300 UT)

Community:  Universe    Password: iota2011


Wednesday, July 20  1900 PDT   (0200 UT on the 21st)

Community:  Universe    Password:  iota2011


Thursday, July 21  1900 PDT   (0200 UT on the 22nd)

Community:  Universe    Password:  iota2011


Watch the Occultation LIVE!!!

Scotty Degenhardt will be broadcasting LIVE using:



BROADCAST SCHEDULE (All times in PDT. Add 2 hours for CDT):

- Throughout the day of Monday July 18th 2011 I will be broadcasting my pre-event preparations as I ready my 18 individual sites.

- 8:30PM I expect to be streaming live video and will give a live equipment tour.
- 9PM Civil Twilight begins and as soon as I can acquire the first visible star I will prepoint the first station, then the action starts!!!
- From 9:10 PM to Tuesday 3AM I expect to be on the road hightailing it to the next 17 sites to deploy.

- By 3AM I expect to have deployed 17 of the 18 stations and will have arrived at my final location where I will broadcast the occultation LIVE
at +59km North of centerline.
- OCCULTATION EVENT should occur somewhere between 3:24 to 3:26 AM!