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Element file to use with Occult
Occultations by 3200 Phaethon 2020-2022
Horizons orbital elements file
The next predicted events are not until 2021
     Nov. 4, South America
     Nov. 5, Europe
The (3200) Phaethon occultations of early October 2020

Can you, and/or others you know, travel to the narrow path for the occultation by (3200) Phaethon Monday morning, to make a valuable observation to learn more about this strange NEO? Just after 9:17 UT on Monday morning, Oct. 5, Phaethon will occult a 11.2-mag. star in Cancer in its narrow path across the s.e. USA, as shown in the attached maps. A central event will last only 0.2s, so it will be challenging.

Steve Conard has posted the Google map for the Oct. 5 am Phaethon occultation, visible in a narrow strip from north of San Antonio, TX to north of Charleston, SC [the small-scale map I sent last night, showing times along the path and with the RA and Dec of the 11.2-mag. star in the upper left (in Cancer), is posted at while the interactive Google map is  at - the dark gray lines, marking what I believe are the 2-sigma limits, are generated using offset values of 6.0 and -6.0]. I hope that a few observers can travel to this narrow path, to get another high-accuracy astrometric point that would be valuable for refining the orbit, and Phaethon’s non-gravitational parameter, caused by spewing off the rocks that cause the Geminids, over the good determination from the 2019 occultation observations. I think the real path errors are about 3 times the small 1-sigma error bars shown on the Google map. Mostly clear skies are expected along most of the path, but predicted cloudiness increases towards the Atlantic coast. You can see my IOTA meeting presentation about the highly successful 2019 Phaethon occultations, the fourth from the bottom at .

For finding the target star, you can point your scope at some brighter stars west of the target, and let the Earth’s reliable rotation bring the target into your video FOV. A good opportunity exists with 5.9-mag. omega1 Cancri = 2 Cancri, SAO 79861, only 7.3 minutes before the occultation. It can be tweaked (with the pre-point offset in dec. reduced from 4’ to 1.8’) with an 8.1-mag. SAO star 2.1 min. before the event. And there’s a brighter chance 1.4 hours before, with 3.1-mag. epsilon Geminorum (Mebsuta); point your finder scope to it (or better, about 0.3 deg. north of it) 1h 24m before the event. Then, 1h 12.7 min. before the occultation (or 11.3 min. after the epsilon Gem pointing), 5.7-mag. 37 Gem will be near the center of the finder FOV. Center it in the main (video) FOV, and then the target star at event time will be only 3’ north of where 37 Gem was. If it will help, this evening I can generate some Guide8 charts showing both the finder and video FOV’s and email them to you, so you might test early tomorrow morning, and of course, then use them Monday morning for the observation.

Another thought - if the occultation can be recorded from two or even three stations, then any short event in one recording might be confirmed with one at an adjacent station. Certainly, do use the largest scope(s) that can be transported to the path. The duration is 6 frames, so the S/N should be high enough to say “no star” for those occultation frames, and “yes, star” for many adjacent ones; the PyOTE analysis should then be able to give a good “false positive” report.

Steve Preston wrote:

Observers should note that this event will be extremely short duration.  The predicted maximum duration is only 0.2 seconds.  You should utilized larger aperture scopes to have any hope of extracting an event time out of the usual scintillation noise.

Sorry for the late notice. I plan to give a talk about the 2019 Phaethon occultations at the online Division for Planetary Sciences of the American Astronomical Society later this month, so I decided to compute future occultations by the NEO through the end of 2023, since JAXA’s DESTINY+ mission plans to launch in 2024. As luck would have it, two of the better events happen this weekend, the other one being Sun. morning across s.w. Europe. I think the predictions should be pretty accurate since I used the latest #712 orbit from the JPL Horizons site, the same that was used to predict the 2019 Oct. occultations so well, and the osculating epoch for the elements is 2020 Oct. 3.0. Good luck!

David Dunham
Interactive map
Interactive map
Google Earth file
Path coordinates
Pre-point star list