International Occultation Timing Association
Campaign to observe 5.5-mag. (1400) Tirela occín Mon. am, Jan. 6, n.L.A., n. PHX, s. Dallas to s. GA

Steve Messner has created a page for this occultation at http://occultationpages.com/events/20200106_1400_Tirela.html including links to Steve Prestonís charts, and path and NWS cloud-cover forecast maps (areas along the path are expected to be mostly clear). Besides the Phoenix and n. L.A. areas, the path crosses the USA, just n. of Truth or Consequences, NM; just s. of Dallas, TX, but getting rather low east of there (to s. Georgia); also visible from northern Honshu, Japan. The prediction has been updated with the help of Gaia observations of Tirela analyzed at JPL.
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We plan to set up as many stations as we can, in a deployment rather similar to what was done for Leucus, but with much smaller telescopes for the much brighter star, on the north side of Phoenix, and up north of New River. The occultation will occur at 3:19am MST (10:19 UT) Monday morning, Jan. 6, and a minute later over the L.A. region. Please let me know if you might be able to help our effort for this rare bright event, or to observe it with either our or your own equipment, from home or from a mobile site. The path is also predicted to cross the San Gabriel mountains north of Los Angeles, but the path is uncertain enough that an occultation is possible over Pasadena, the San Fernando Valley, Simi Valley, and possibly areas a little farther south. In central Arizona, observers as far south as Gilbert and Tempe are urged to also try to observe, at least with binoculars from your home. And observers in a wider area, about 500 km wide centered on the path, might observe an occultation by a satellite of Tirela, but any such events are likely to be very short, since even a central occultation by the main body is expected to last only 1.3 second.

Tirela is expected to be 15 km in diameter, but with projection, the path will be 23 km wide. The star is 5.5-mag. SAO 113186 = HIP 27560, spectral type K0, at J2000 RA 5h 50m 13.1s, Dec +04 deg. 25í 23Ē, about 3 deg. south of Betelgeuse; a chart showing the path is at http://www.asteroidoccultation.com/2020_01/0106_1400_67752_Finder15.gif but weíll post some better charts on the occultationpages Web site tomorrow (Saturday).


We have extra equipment to video record this occultation, simpler to operate than the SwRI telescopes and cameras that were used for the Leucus occultation, and could use your help to use it to record the occultation at your place, or at a mobile site. If interested, let me know; you can pick up the equipment, and we can show you how to use it to record the target star, at our place in Fountain Hills, 2 blocks east of The Hills restaurant parking lot where we had the Leucus occultation practice. You can meet us either late tomorrow (Sat.) evening, or early Sunday evening, or later that night while we deploy stations along North New River Road, and at sites near I-17 north of New River. If you canít join this effort, you might still make a useful observation of the eventís duration by watching the star with binoculars and recording your event calls with video recording using a smartphone, or better, point the smartphone into a low-power eyepiece of your telescope to record the star. See http://occultations.org/observing/ for basic observing and timing information.

David Dunham, dunham@starpower.net, 301-526-5590
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OW-TirelaSatellitesZone
OW-TirelaNM-MS
OW-TirelaSCalifasOfJan03
OW-TirelaCenAZasOfJan03
USA-NWSasOfJan5PM
pptx file
Link to Steve Preston's prediction
Cloud cover predictions toward bottom of page, updated 1/05 5PM
http://www.asteroidoccultation.com/2020_01/0106_1400_67752.htm
PDF file
Level 3 pre-point charts
Level 4 pre-point charts