Special Asteroid Events

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Special Asteroid Events

Updated 2018-06-09

Previous Events are >> HERE

Future Asteroid Event Details

Double star code. 
1 = WDS, 2= double in other sources (4th interferometric, or star catalogue flag),
4 = Variable star (listed in AAVSO Index file).
Values are cumulative, thus, 
a 5 = a 1 (WDS) plus a 4 (AAVSO) and a 6 = a 2 (other sources) and a 4 (AAVSO).

For GoogleEarth KML files, please right click and SAVE AS, then open in GoogleEarth - This website prefers GoogleMaps


2018 IOTA Occultation Campaigns

In many previous years, the International Occultation Timing Association (IOTA) chose to hold their annual meeting
in a location during the weekend close to one of the better occultations of the year, so that IOTA members could
"kill two birds" with one trip. For example, in 2016, we met in Stillwater, OK, within easy range of the best
Aldebaran lunar grazing occultation of the current series, while last year, we met in Carson City for one of the
best North American asteroidal occultations, involving 241 Germania and a 9.0-mag. star. But this year, we decided
to meet instead not for any special occultation, but in conjunction with (the day before) the North-East Astronomy
Forum (NEAF), one of the largest meetings of amateur astronomers, in order to reach more new observers, a goal that
was successfully achieved; IOTA also ran a successful booth and gave a pro-am presentation at NEAF.

The earlier meetings resulted in campaigns for the target occultations, often successful, but the ones in 2015 and
2017 were clouded out, in spite of being in desert cities (in 2017, although Germania was clouded out, there was a
successful effort for an occultation of a fainter star by the asteroid 357 Ninina that occurred two nights before the
Germania event). This year, we still want to mount an IOTA campaign that is separate from any formal IOTA meeting,
for what we consider to be the best occultation of the year in North America. This is effectively like the "Occultation
Day" suggested by Atila Poro of IOTA - Middle East; he envisioned a day similar to Astronomy Day. We think that it is best
for each region of IOTA to have their own Occultation Day campaign, to observe the best occultation in their region, and
of course, then this will be a different day each year. But then, what is "best"? We decided to have two campaigns, one
for the most valuable occultation, and the other for the most observable, that might be observed by many with small
portable systems that could even be transported by airplane.

The most valuable was easy to select; itís the occultation of a 12.9-mag. star by Pluto that will occur on 2018 August 15,
around 5.5h UT, a Tuesday night, visible from most of the USA. The currently-predicted northern limit extends approximately
from central California to Lake Superior, while the central line, from near which a Plutonian atmospheric central flash is
probable, crosses Georgia. Note that an occultation dimming in the atmosphere might be observed from locations a few
hundred km north of the actual northern limit. This is a relatively faint event, but relatively bright for occultations
by Pluto and other TNOís; this is the brightest star to be occulted by Pluto since the 2015 June event in New Zealand
and Tasmania. The occultation can best be recorded with large telescopes at fixed observatories, of which there are
many in the predicted path. If you have occultation recording equipment but not a large-enough telescope, find an
observatory at a college near you and offer to use your equipment there. More information about this occultation is at
http://lesia.obspm.fr/lucky-star/predictions/single.php?p=7722 and more information about it (finder charts, etc.) will
be posted on IOTAís Web sites closer to the time of the event.

For the most observable, weíve selected the rank 100 occultation of 7.2-mag. ZC 782 = SAO 77043 = HIP 24403 (spectral
type A2, in Taurus) by the 79-km asteroid (80) Sappho that will occur around 8.8h UT of Sunday, September 16, in a path
extending from northern California (Sacramento) to Reno to Salt Lake City to Wisconsin to s. Ontario to Maine and s.
Nova Scotia. Being in the middle of the weekend will facilitate travel, and there will be many hours of dark time before
the event, for those wanting to pre-point one or more remote stations. Finder charts of different scales and other event
details are at http://www.asteroidoccultation.com/2018_09/0916_80_56486.htm . More information to help coordination for
the event, including pre-point charts, will be posted during the weeks before the occultation.

David Dunham,



The region of visibility is shown in Fig. 1, between the two thin dark blue lines, marking the occultation limits, the location where the starís intensity is predicted to fade by 50% in Plutoís refracting atmosphere, until the star starts to brighten again. The red dashed lines show the outer 1-sigma locations of the limits. The light blue lines outside these limits mark the places where the fading will be by only 1%, the smallest drop that might be detected with large telescopes under good conditions with sensitive detectors. The current prediction was recently updated with a refinement of the ephemeris of Pluto using an analysis of past occultations with Gaia DR2 data for the stars.




This is the official list of events for which Southwest Research Institute may provide funds to IOTA for multi-station expeditions as described
at the IOTA annual meeting October 20, 2012. Observers who have multi-station capability that are interested in supporting specific occultations
shown in this short list are invited to email pdmaley at yahoo dot com so that we can gauge the potential level of participation. After reviewing the 
list please indicate which event(s) you would like to support and from which general area (e.g. south Texas, northern California, etc.). 
Announcements will be made prior soliciting observers who might have a portion of their travel expenses covered.
*Nothing Current*

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