Occultation of 11.8-mag. star by Titania on 2023 November 20/21 - Updated 2023 Nov. 19

The relatively bright stsr might allow detection of a possible thin atmosphere of Titania

View of Uranus system for the occultation has been added

by David Dunham

This important rare occultation of an 11.8-mag. star by Uranus’ largest moon, Titania, 
will occur around midnight Monday night Nov. 20/21, actually several minutes after 
5h UT of Nov. 21 UT. Southern Canada and most of the lower 48 States will have an 
occultation, although the southernmost States, especially those in the east, miss the show.
Here is the Occult map showing the predicted region of visibility of the occultation.
Titania will be about 30 arc-seconds east and a little south of Uranus during the event, 
so it and the brighter star will be well-separated from the bright planet, as shown in 
this view of the Uranus system for the event produced by Occult4.

Two plain text files give predictions for the occultation for a few dozen of the 
larger cities in or near (within 2-sigma of) the predicted path of the event.
They were computed from an Occult .site file that was concatenated from .site 
files for N. America, europe, and the world, so there are duplicate entries for 
many cities. I think the most useful file is the time and circumstances file
that gives the probability of the event at the location, the Univeral Time of 
the middle of the occultation, and in the last columns, the altitudes of Uranus 
(and the star), and the Sun. The cities are listed from north to south by their 
distance from the central line, so you might download the file, and edit it with 
Notepad or Word to find a city near you. The other file gives contact times (D and 
R) but only to the nearest 0.1 minute, so it doesn't give much new information for 
an event that lasts only a little more than one minute. But you can get an idea of
the duration that might be expected for your location. The data are listed in 
alphsbetical order by city name. No times are given for locations outside the 
predicted path.

Observations of this event are of high value, as explained in this message by 
Dr. Marcelo Assafin; please read it. He stresses that prospective observers 
should sign up for the event with the Lucky Star Occultation Portal.
About two dozen have already signed up for the event on Occult Watcher as 
you can see on the OWcloud page that has finder charts and much detail about 
the event; if you are one of those on OW, you are encouraged to also sign up 
on the Occultation Portal. Please read more important remarks from Dr. Assafin 
in this recent message.

A good paper about an occultation of a fainter star by the Uranus moon Umbriel 
that was well-observed across the USA in September 2020, was published recently and is
openly available from MNRAS. Read Marcelo Assafins remarks about it in this message.
Most of the observers of that event are in the path of this Titania occultation.

Page set up by David Dunham, 2023 November 16, updated Nov. 18, and Nov. 19
Cell phone 301-526-5590
email dunham@starpower.net