IOTA Occultation Campaigns
Observing campaigns are events that provide an opportunity for training new observers as well as general interaction among all observers. And the observations collected during a well-observed occultation give important information on the asteroid shape, possible detection of an asteroidal and/or stellar companion, and a well determined asteroidal position.
IOTA Campaign 2024
Three events have been selected for 2024:
July 15: (5361) Goncharov occults 9.2 magnitude TYC 6374-00593-1, an event that should be within reach of smaller scopes. The path starts in Maine just ahead of sunrise and travels down the Eastern coastal states through the Florida panhandle. We will need people to coordinate this event, particularly trying to match new observers with experienced ones or possibly arranging training sessions, in person or over Zoom. A document on establishing a station and retrieving event prediction with OccultWatcher Cloud is here.
We have prepared a training exercise to help observers prepare to this event. Anyone can participate in this training exercise even if you are not near the path.
The event occurs about 3:51 AM EDT at an elevation low enough to cause problems for observers with constricted sites. For example, at a site near Bryantown, MD, the altitude will be 28 deg. The altitude will be lower than that for sites at the northern end of the path in Maine and higher at sites near the southern end in Georgia. We looked for opportunities to practice between 10 and 11PM in days before the event and found two stars close in magnitude that will be at about the same elevation and azimuth as the star being occulted by Goncharov will be in the early hours of July 15. The Sun altitude will be below -8 deg (dark enough to find Polaris) after 9:20PM EDT and below -12 deg (dark enough to find stars of 9th magnitude) after 9:45PM EDT along the occultation path. Observers, particularly ones using fixed site telescopes, can use these practices to determine if their chosen observing site may not have sufficient visibility for the event.
The two stars are SAO 183894, an 8th-mag star which will be at the event altitude and azimuth about 10:05PM and SAO 184522, a 9th-mag star which will be there about 10:51PM. We suggest that, for practice, you find the first target on the evening of July 11 or 12 and capture a 3-minute recording of your target centered on 10:05 (from 10:03:30 to 10:06:30). If you haven’t found that star, continue searching for the second target and record centered on 10:51 PM (from 10:49:30 to 10:52:30).
Our suggestions for practice and finder charts are here. Instructions for observers who are not close enough to the predicted path to observe but want to participate in the training exercise are included in the practice instructions. A practice session report spreadsheet is here.
Sept 14: (4337) Arecibo occults 10.8 magnitude TYC 1995-00394-1, a somewhat more difficult event with an under 1-sec duration, but one of great interest for the potential to collect more observations of its moonlet. That path crosses the USA from California through Ontario to sunrise in Quebec.
Sept 22: The waning gibbous Moon passes through the Pleiades in the early hours of the day, before sunrise, with four grazing occultations and multiple reappearances of bright stars. We also plan to have a Zoom session led by David Dunham on generating occultation predictions with Occult.
IOTA Campaign 2023
The event chosen for the 2023 IOTA annual observation campaign was the (704) Interamnia occultation of TYC 2413-01489 on Sept 13. This event, as can be seen from the plots, passed near many observer locations, traversing a West to East wide path that crossed the country from northern Baja California and southern California to the Great Lakes, and on into Canada where the event became unobservable in bright early morning twilight.
Seventeen observers reported observing from 22 stations. The resulting data are fitted to a DAMIT image as can be seen in the reviewed asteroid occultations presented on the web site www.asteroidoccultation.com/observations/Results/Reviewed/ under the listing for 2023.
Near Earth Asteroid Occultations for 2024
Observing occultations by NEAs is a very interesting and challenging endeavor, but a rewarding one. Results from occultations have led to better knowledge of their orbits and increased precision in determining whether or not a specific object may pose a risk of a damaging impact on Earth. Improvements in predicting the narrow occultation path across the Earth’s surface and improvements in observing equipment has brought precise timing of these very short events within the reach of more observers.
More about NEA occultations in North America during 2024, including some information about campaigns for them, is given here.
These special campaigns are generally not announced well in advance so they will not be promoted on these pages. They are normally announced to the IOTAoccultations groups.io list.