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 19^th. 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. 

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)

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
http://www.poyntsource.com/New/Google/20110719_23903.HTM

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)

http://evo.caltech.edu/evoNext/koala.jnlp?meeting=vsvivIe8eMI2Ilasa2Itas

Community:  Universe    Password: iota2011

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

http://evo.caltech.edu/evoNext/koala.jnlp?meeting=MMMeMn2v2sDsDs9a92D29M

Community:  Universe    Password:  iota2011

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

http://evo.caltech.edu/evoNext/koala.jnlp?meeting=MIM9Ms2D2nDnDn9M98Da9I

Community:  Universe    Password:  iota2011

Watch the Occultation LIVE!!!

Scotty Degenhardt will be broadcasting LIVE using:

http://www.ustream.tv/channel/scotty-sky

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

MONDAY JULY 18TH
- 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.

TUESDAY JULY 19TH
- 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!