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 2023

The event chosen for the 2023 IOTA annual observation campaign is the (704) Interamnia occultation of TYC 2413-01489 on Sept 13. This event, as can be seen from the plots, passes near many observer locations, traversing a West to East wide path that crosses the country from northern Baja California and southern California to the Great Lakes, and on into Canada where the event becomes unobservable in bright early morning twilight.

The event details are:

Event Details

Date: 13 September 2023, Time: Between 10:14 to 10:25 UT depending on position along the track. (10H UT is 3AM PDT, 4AM MDT, 5AM MST and CDT, 6AM EDT.)

Asteroid: (704) Interamnia, visual magnitude 11.1

Star: TYC 2413-01480-1 or SAO 58382, A G0 star of visual magnitude 9.1, in Auriga.

Magnitude drop: 2.7. Duration of central occultation: 17.3 sec

Prediction generated by Steve Preston.

With this long predicted duration, even a Mighty-Mini will be able to record the observation with a RunCam and appropriate integration. Observers with an 8-inch or larger telescope should be able to see the asteroid approach the star.

More information on training opportunities and observation coordination will be provided at this site, at the IOTA 2023 annual meeting, via discussions on the and through occultwatcher. Observers interested in more information can download the xml file provided by Derek Bright here and generate predictions for their own sites with Occult.

Testing and Prepoint Charts

Prepointing telescopes is the technique of pointing a telescope to the altitude and azimuth at which the event is predicted to occur. Selecting a star along the prepoint line that is of similar magnitude to the occulted star is also a useful technique to determine if the event is going to be visible from a specific location and if the user’s equipment can record the event. Since the event occurs in the early morning of September 13, we have selected specific useful stars located along the prepoint line at around 10 PM and 11PM on September 11.

Charts are presented below, grouped by time zones.

Charts for the Eastern Time zone are in this document

Charts for the Central Time zone are in this document

Charts for the Mountain Daylight Time zone are in this document

Charts for the Mountain Standard and Pacific Daylight time zones are in this document

A presentation on generating and using prepoint charts is in this document

Special Events and Bright Main Belt Occultations for 2023

Special events, most requiring considerable experience in occultation observing, are being observed in a coordinated fashion. Some are announced on the user group forums, but others are with self-selected observers who are known to the individual coordinator as able and willing to observe. These include occultations by asteroids of critical importance for upcoming spacecraft missions or asteroids which have a potential for Earth impact. For information about other bright main-belt occultations during 2023,see this document . There is a page for occultations of main-belt asteroids of special interest (those with satellites or odd shapes, mainly determined from previous occultations) here .   The best source for near-term predictions of occultations by distant Solar System objects, including Trojan asteroids, is OccultWatcher.

Near Earth Asteroid Occultations for 2023

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 2023, 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 list.