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Assessing Pluto from Afar
Worldwide, Ground-based Astronomy Campaign Supports New Horizons

June 6, 2014

When New Horizons speeds past Pluto in July 2015, its set of sophisticated cameras and sensors won’t be the only high-tech “eyes” trained on the distant planet and its moons. The New Horizons mission team has officially kicked off its two-year-long Earth-based Observation Campaign, an opportunity for astronomers around (and above) the globe to observe Pluto while New Horizons approaches and passes it.

“New Horizons offers a once-in-a-lifetime opportunity to measure in situ the state of the Pluto-Charon system,” said Richard Binzel, a New Horizons co-investigator from Massachusetts Institute of Technology, who leads the campaign. “After decades of measuring the system through Earth-based telescopes we know it is very dynamic, and also realize that the New Horizons flyby provides a snapshot of a single moment in the system. We want to establish an extensive context using Earth-based telescopes for the state of the Pluto system at the time of the flyby, including evolving trends in the system for at least one year prior- and post-flyby.”

Here’s how the program works: the New Horizons team puts out international calls for its “most wanted” observations, encouraging individual or teams of planetary astronomers to propose observation campaigns to various telescopes. The program’s five phases match the separate stages of New Horizons’ own encounter at Pluto, such as pre-encounter (now through October 2014), immediate approach (April-May 2015), encounter (June-August 2015), immediate post-encounter (September-October 2015) and later post-encounter (April-December 2016).

“Of course, simultaneous ground- and space-based measurements when New Horizons flies past Pluto [on July 14, 2015] are important for calibration and context,” Binzel said. “But observations before and after the flyby are just as important.”

What observations can the New Horizons team expect from Earth?

The team unveiled the campaign at last summer’s Pluto Science conference, and has asked more than a dozen of the world’s leading observatories to support the mission. New Horizons scientists led workshops on the program at the European Planetary Science Congress last September and the AAS Division for Planetary Sciences meeting in October, and the team has launched a website that includes sections for submitting proposals and finding collaborators, among other resources.

“The campaign relies on individual investigators responding to calls for observations,” said Joel Parker, a New Horizons co-investigator from Southwest Research Institute and deputy lead on the New Horizons ground-based observation coordination team. “We especially want to identify how these programs can complement each other.”

For more on the New Horizons Earth-based Observing Campaign, visit: Contact the observation coordinating team at

Early Results
In early May, using the 4.2-meter William Herschel Telescope in the Canary Islands (pictured below), New Horizons Science Team co-investigator Dale Cruikshank led a team that collected spectral measurements of Pluto. Cruikshank and colleagues will use the data to help determine the composition of the patchy pattern of non-ice materials on Pluto’s surface. 

“This yellow-colored material is presumed to consist of complex organic chemicals made by sunlight and cosmic rays impacting on Pluto’s ices [nitrogen, methane, carbon monoxide and others],” Cruikshank said. “The new data from the big telescope in the Canary Islands, compared with lab data in which Pluto’s surface is simulated and exposed to ultraviolet light, will test these ideas and lead to an improved understanding of Pluto’s chemistry.”

Cruikshank’s team includes Noemi Pinilla-Alonso, of the University of Tennessee at Knoxville; Vania Lorenzi, of the Fundacion Galileo Galilei; and Javier Licandro, of Instituto de Astrofísica de Canarias.

William Herschel Telescope Stars
Photo courtesy of the Isaac Newton Group of Telescopes, La Palma

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