April 18th Observations show that (772) Tanete may have a large satellite - new 2004 May 1

During the morning of April 18, (772) Tanete occulted 10.5-mag. 
TYC 6849-00321-1 along a north-to-south path across the western USA. 
Jim Stoffaire video recorded an 11.1-second occultation using a 25cm 
telescope at Sherwin Hills, California, near his home in Bishop.    
His duration was close to the predicted central duration for the 
asteroid, expected to be 117 km in diameter, and his time was close to 
that predicted for the event by Steve Preston.  Click here 
for Preston's map of the predicted path, with a more detailed map of 
the path across California and Nevada here.

Two minutes before Jim's observation (we are sure of that now from 
careful analysis of the tapes; the WWV time signals were very clear), 
Red Sumner at Dayton, Nevada (near Carson City) timed a 4-second 
occultation of the star observing visually with a 20-cm telescope.  
Unfortunately, he assumed that the show was over after the star 
reappeared and stopped observing about 30 seconds later; Tanete itself 
probably occulted the star at his location as well.  Richard 
Nolthenius timed a short probable blink at Carrizo Plain, California, 
southwest of Bakersfield; his event lines up well with Jim 
Stoffaire's, so he probably did have an occultation at the actual 
western edge of the path.  Richard has posted his observation here.

All of the observations of this event are given here in the Occult 
program's format that is described here.  A plot of the 
observations in the sky plane at Tanete is here where 1 is
Jim Stoffaire, 2 is Steve Preston's prediction (was quite accurate), 
3 is Richard Nolthenius's blink, and the break in Red Sumner's trail 
is marked by two 5's at the bottom of the figure, but as noted above, 
he stopped observing before his line reached the Tanete circle shown 
at the top.  The circle fitted to Stoffaire's and Nolthenius' times is 
141 km in diameter, larger than the predicted size.  Sumner's 
observation indicates a possible satellite about 40 km in diameter 
1260 km (a plausible 9 diameters) from Tanete.  Jim Stoffaire looked 
at his video tape closely and found no event corresponding to Sumner's 
two minutes before the main event; the diagram shows it is unlikely 
that the satellite would have occulted the star at his location.  
Richard Nolthenius was closer to Sumner's path, but we need to find 
out from him exactly when he started observing; he just says that 
there were no events other than the blink "for 4 minutes centered on 
12:06 UT".  That means that he started observing very close to the 
time (before or after?) of closest approach of the satellite shadow at 
his location.

Tanete is moving rather rapidly south, so observers in the Southern 
Hemisphere have a better chance for directly resolving this possible 
satellite during the next few months as the asteroid reaches 
opposition.  There will also be another occultation by Tanete, on 
May 20th, predicted by Steve Preston with details at his Web site.
That occultation is predicted to be visible from Florida 
(Jacksonville and Gainesville areas), southern Mexico, New Zealand's 
North Island, and southeastern Australia.  But observers in a much 
wider area are encouraged to try to observe to possibly catch an 
occultation by Sumner's satellite, from Missouri to Florida 
(northeast of there, twilight will be too bright) to Cuba, and 
westward to Texas and most of Mexico, and down to Costa Rica; and 
througout New Zealand and eastern Australia.

David Dunham and Rohith Adavikolanu