The NASA Lucy Mission will fly by the binary Trojan asteroid system (617) Patroclus/Menoetius in 2033. Ground-based stellar occultation data is essential both for mission planning and our understanding of minor planets. On Sunday, May 9 at 8:37:55 UT, the shadows of these 113km and 108km asteroids will sweep over the southern US as they occult an 11.5 magnitude star in Scorpius.
To measure this event, roughly 20 teams affiliated with RECON will measure Patroclus from primarily fixed site locations (orange chords) while another 30 teams will measure Menoetius from primarily mobile sites deployed in Texas (purple chords).
On Thursday/Friday night, April 15-16, Hi’iaka (a satellite of Haumea) will be occulting a bright star (magnitude 11.9) with a shadow path centered almost perfectly over the RECON network! The occultation prediction below was updated just this week based upon a successful occultation chord obtained on April 6 at Oukaimeden Observatory in Morocco. This event (starting around 6:30UT on April 16 for locations west of Colorado) is an exceptional science opportunity to better understand and characterize this moon and the Haumea system. We look forward to having all RECON hands on deck to capture this important event!
As a follow-up to John’s posting of the Jupiter-Saturn conjunction, I thought I would post the below image. This is a composite image of the individual planets from a number of videos taken that evening. The videos were taken very early after sundown to take advantage of the elevation of the planetary conjunction and the somewhat better seeing that provided. The telescope was a polar mounted 12” Meade LX200GPS with a 3.3 focal reducer using a Watec 910 HX black and white camera. Each short video was made with an exposure appropriate for the planet as Jupiter is significantly brighter than Saturn. A slightly longer exposure was also taken to get the three moons of Jupiter. The better image of each planet from the videos was then cut and pasted into this 720 by 480 composite. The relative positions of the planets is somewhat different than John’s Stellarium rendition, as in this one north is up.
RECON is excited for our second occultation campaign of the 2020-21 academic year involving Kuiper Belt Object 04VV130 in a 3:2 resonance with Neptune. This event will occur a quarter hour before 9PM PST/10PM MST on the evening of Winter Solstice, Monday December 21. In addition, on this evening Jupiter and Saturn will be less than 0.1 degree from each other and visible in our telescope camera field of view and eyepiece. This is the closest Jupiter-Saturn conjunction visible in the night sky in the past 800 years! We highly encourage ANYONE with a telescope of ANY SIZE to check out Jupiter and Saturn this evening in the hour following sunset. Below is a quick shot from Stellarium of how close these two largest planets will appear. Should be quite the telescope sight!
It’s been a busy summer. RECON has been acquiring new QHY systems for our occultation network, and we distributed 24 of these during a recent deployed campaign involving a comparable number of teams that travelled to northern Oregon/southern Washington to measure the Trojan Asteroid Eurybates on September 16 UT. There were significant challenges faced during this campaign due to smoke from regional fires, but data was collected by a handful of teams and there was lots of learning about the QHY system and deployed campaign logistics.
We are currently pulling together an additional 20 camera systems to distribute to our remaining RECON teams. We hope to distribute these out to teams by late November/early December after we have completed our NSF Proposal for RECON 2.0 due on November 15. For intervening RECON campaigns, half of our teams will collect data using the QHY and the other half will use their MallinCam systems.
The first of the campaigns of the academic year will occur on October 21 around 11:34UT, which is early that Wednesday morning. This event will involve Centaur 02QX47, currently located just inside the orbit of Neptune. This is a high probability campaign opportunity with 33% probability of detection. Thanks to all of our teams for indicating your availability and any existing equipment concerns through the RECON Campaign Signup Form.
This is a very exciting campaign for RECON teams from Klamath Falls, Oregon down to Yuma, California. (9142) Rhesus is a Trojan Asteroid located in the L5 Lagrange point that trails 60 degrees behind Jupiter. The uncertainties are very low for this prediction, making this a very strong occultation opportunity. The shadow track is shown below. If you are within the range of the shadow track, make sure to sign up!
To view the event page and sign up for this event, click here.
From August through November 2019, RECON conducted six occultation campaigns involving two Centaurs, three Resonant Objects, and one Classical Kuiper Belt Object. In addition, five teams from Northern California and Southern Oregon deployed a mobile campaign to measure Leucus, a Trojan Asteroid that the NASA Lucy mission will visit in the coming decade.
Following a hiatus during the holiday season between Thanksgiving and New Years, RECON is ringing in the new decade with FIVE events during January 2020. We have an unusually dense number of campaign opportunities this month that hope to pursue. Check out the RECON Observation Campaigns Page for a listing of these upcoming events!
We’d like to take this opportunity at the close of the 2010’s to thank our hundreds of RECON volunteers (students, teachers, and community members) from over 60 communities for their countless hours of participation in over 40 occultation campaigns over the decade. Of these, we have successfully measured 9 trans-Neptunian Objects and contributed to our knowledge of the outer Solar System and its formation.
As many RECON team members have noticed, the frequency of occultation campaigns drops off during the summer months.
Interestingly, the reason for this has to do with the orientation of our Milky Way Galaxy and the plane of our solar system (known as the ecliptic), as well as the tilt of Earth’s axis. During the summer, daytime is longer but nighttime is shorter, and while the Sun is high in the northern sky, the ecliptic is low in the night sky. In addition, the ecliptic crosses through the center of our galaxy in the constellation Sagittarius, which is up in the night sky the longest during the summer. Because it is difficult to discover trans-Neptunian objects within the crowded star field of our galaxy, as well as their low positions in the sky and shorter nights, there are fewer high probability events that we can pursue during the summer.
As we approach the start of the new school year, however, conditions become more favorable for RECON campaign events. Toward this end, we have already announced two upcoming events on the night of August 16-17 involving Centaur 08YB3 and the night of September 3-4 involving Centaur 13NL24. In addition, looking at the RECON Campaign Prediction Page, there are eight additional campaign opportunities before the New Year with probabilities greater than ~20% that we are currently considering as full network campaigns. The 2019-20 academic year promises to be the most productive occultation cycle of our project to date!
An Interesting Main Belt Asteroid and Recent Occultation Observation
From Wikipedia: “Eugenia was discovered on 27 June 1857
by the Franco-German amateur astronomer Hermann Goldschmidt. His instrument of discovery was a 4-inch aperture
telescope located in his sixth floor apartment in the Latin Quarter of
Paris. It was the forty-fifth minor
planet to be discovered. The preliminary orbital elements were computed by
Wilhelm Forster in Berlin, based on three observations in July, 1857.
Eugenia is a large asteroid,
with a diameter of 214 km. It is an
F-type asteroid, which means that it is very dark in coloring (darker than
soot) with a carbonaceous composition. Like Mathilde, its density appears to be
unusually low, indicating that it may be a loosely packed rubble pile, not a
In 1998 astronomers discovered that Eugenia had a moon. It was the first discovery of a moon orbiting an asteroid by a ground based telescope. The discoverers name the moon Petit-Prince. The moon, about 13 km in diameter, orbits Eugenia in about 5 days. Discovered in 2004 a smaller moon, at about 6 km, orbits Eugenia every 4.7 days and is designated S/2004 (45) 1.
Earlier this month, 45 Eugenia was predicted to occult an 11.8 magnitude star (UCAC4-369-175949) in the constellation Sagittarius. The maximum duration of the event was predicted to be 20.6 seconds with a magnitude drop of 0.4 – 0.5. The predicted path extended from central Montana, through Idaho, northern Nevada and northern California. An announcement of the event was distributed to observers across the west in an attempt to perhaps observe the known moon, Petit-Prince.
Predicted event time was
approximately 08:12:45 +/- 2 sec UT (01:12:45 PDT). There have been a number of previous
occultation events by Eugenia over the years, with 13 positive chords recorded
in 2014 and 7 positive chords in 2017.
Because of its size, Eugenia is a fairly bright object at mag 11.2 and is easily discernible from the target star as seen on the two images below. These images were extracted from integrated video taken as the asteroid approached the target star and after the predicted event. Time stamp data for each of the images is shown at the bottom of each frame.
I was able to record the event
with a 304 mm SCT equipped with a 3.3 focal reducer, WAT910 HX B/W video camera
and IOTA-VTI time stamp inserter. Video
was recorded with no integration at 2X.
Light curve data and occultation event timing extraction was completed
using a new set of programs authored by Bob Anderson in conjunction with the
North American International Occultation Timing Association (IOTA).