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Planetary RadioAugust 22, 2018

Pluto Occults! Join Us on the Mountain

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On This Episode
Franck Marchis head shot
Franck Marchis

Senior Planetary Astronomer, SETI Institute & Chief Scientific Officer, Unistellar

Chris Hendren

Oceanside Photo and Telescope

Joana Oliveira Marques

Observatory of Paris PhD Candidate

Bruce Betts Head Shot 2015
Bruce Betts

Chief Scientist / LightSail Program Manager, The Planetary Society

Jason Davis thumbnail
Jason Davis

Editorial Director, The Planetary Society

Mat Kaplan
Mat Kaplan

Planetary Radio Host and Producer, The Planetary Society

Pluto passed in front of a star on the evening of August 14. Mat Kaplan joined pro and amateur astronomers on a mountain to observe this rare event. It may reveal more about the dwarf planet’s tenuous atmosphere and other properties. Everyone hopes that Mars Exploration Rover Opportunity will phone home when the waning worldwide Martian dust storm allows the robot to charge its batteries. Digital Editor Jason Davis tells us about the online mistake that had some fans believing it had already happened. And it will be “raining fire in the sky” when Bruce Betts drops another What’s Up segment.

Preparing for the Pluto occultation

Chris Hendren

Preparing for the Pluto occultation
At the Lake Henshaw Overlook preparing for the Pluto occultation with an Unistellar eVscope prototype and a large Celestron C14 telescope. From left to right: Martin Costa, Franck Marchis, Joana Oliveira Marques and Mat Kaplan.
Laptop used to control a telescope to view Pluto occultation

Mat Kaplan

Laptop used to control a telescope to view Pluto occultation

Pluto in enhanced color


Pluto in enhanced color
This photo combines a mosaic of four black-and-white, high-resolution LORRI images with lower-resolution color data from the Ralph MVIC instrument to create a portrait of Pluto's vari-colored terrains. MVIC takes photos through red, blue, and near-infrared filters, so the images enhances contrast among terrains with different surface compositions.

Pluto’s majestic mountains, frozen plains and foggy hazes


Pluto’s majestic mountains, frozen plains and foggy hazes
Just 15 minutes after its closest approach to Pluto on July 14, 2015, NASA’s New Horizons spacecraft looked back toward the sun and captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The smooth expanse of the informally named icy plain Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 3,500 meters high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. To the right, east of Sputnik, rougher terrain is cut by apparent glaciers. The backlighting highlights over a dozen layers of haze in Pluto’s tenuous but distended atmosphere. The image was taken from a distance of 18,000 kilometers to Pluto; the scene is 1,250 kilometers wide.

Trivia Contest

This Week’s Prizes:
A svelte Planetary Radio t-shirt from the Planetary Society Chop Shop store and a 200-point astronomy account.

This week's question:

Who is the Spitzer Space Telescope named after? (And don’t tell us, “a guy named Spitzer.”)

To submit your answer:

Complete the contest entry form at or write to us at no later than Wednesday, August 29th at 8am Pacific Time. Be sure to include your name and mailing address.

Last week's question:

How many Venus flybys will be required for the Parker Solar Probe to adjust its orbit around the Sun?


The answer will be revealed next week.

Answer to the August 8 space trivia contest question:

John Denver co-wrote Rocky Mountain High, which contains the line, “I’ve seen it raining fire in the sky.” Denver was inspired by viewing the Perseid meteor shower.

Listen more: New Horizons, planetary astronomy, interview, Pluto, atmospheres, podcasts and videos, astronomy, personal stories, SETI, amateur astronomers

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