Changing Planet

Got a Telescope? Pluto Hunters Need Your Help

This week a fleet of astronomers, partly funded by National Geographic, has been in the Pacific region capturing the first of two occultations of Pluto and its moons. Now they need your help to get the second. Find out if you’re in the predicted path of the event, and let team member Leslie Young know if you’re willing and able to lend a hand!  -V


Most of our work today is logistical, trying to find places that are in the new Pluto and Charon shadows. For Pluto, we’ve made contact at a larger telescope in Japan.

To catch the Hydra track in Hawaii, we’ll be spreading ourselves to more sites rather than trying to compare lightcurves from two telescopes at the same sites. We’re looking into adding a telescope at one of the islands in the Kwajalein atoll. This is not trivial, because you can only get there by helicopter.

As you read here, we got the June 23 Pluto and Charon occultation, and we were able to update our prediction for the Hydra shadow. The new prediction for the Hydra path is now crossing areas in Southeast Asia. Are there any telescopes that can help with this observation?

We’re looking for 11-inch or larger telescopes in Indonesia, Thailand, and Malaysia too. Our host in Cebu City, Christopher Go, knows many of the amateur groups there, and we’re making good contacts.  Anyone who is interested in helping out can contact me at


Pluto has one large moon, Charon, and two small moons, Nix and Hydra.  Nix and Hydra were only discovered six years ago, and very little is known about their physical properties. An occultation would give us the first measurement of the size of Hydra. Also, because the four bodies pull on each other in subtle ways that depend on their masses, improving the orbit will help us measure the mass. Finally, we hope to measure the cross-section of Hydra from two different angles, one from occultations and one from the New Horizons spacecraft.


The newest prediction—good to maybe 300 kilometers—is here:

See in particular:


* located anywhere within 300 kilometers of the predicted shadow
* 20 minutes of continuous images taken June 27, 14:42 to 15:02 UT
* 11-inch or larger telescope
* camera with low dead time (less than 0.1 seconds between exposures)

Best is:

* larger telescopes, which will give higher signal
* pairs or clusters of sites where telescopes are spaced 2 to 50 kilometers apart (25 kilometers is ideal)
* wide field-of-view (20 arcseconds), to make finding this crowded field easier
* integrating CCDs that can observe at 0.5 seconds with little time between exposures
* some way of telling the time of the observations
* an additional 20 minutes of continuous images taken June 27, 14:08 to 14:28 UT, in case Pluto’s shadow is actually over Malaysia


Our planning pages (finder charts, stars for star hopping, etc) are at:

Read full news coverage on National Geographic:

Leslie Young

(The Pluto occultation research is supported by NASA’s Planetary Astronomy program, NASA’s New Horizons Mission, the National Geographic Society’s Committee for Research and Exploration, and the Southwest Research Institute.)

—An artist’s concept shows Pluto (largest disk near center), its largest moon Charon, and one of its two small moons, Nix and Hydra, as seen from the surface of the other small moon. Picture courtesy NASA, ESA and G. Bacon (STScI)

  • Amirul Musa

    How long it will be?

  • Glen Roberts

    Wow!!!! this could be fun. I actually live in the Snowy Mountains region of Australia where the skies are always pretty devoid of smog and bright. I live at the bottom of a fire tower with 360 degree uninterrupted views. Form here I have witnessed meteor showers and a clear view of the last comet to pass the planet about 2 years ago.

  • Leslie Young

    Hello Amirul Musa. The drop will only last a few seconds, but we want to put pad on either side since we don’t know *exactly* when the drop will be, and to characterize the unocculted signal.

  • jonisusilo

    This youngest planet of the solar system family, going across the Asia region. Greatly interesting . . .

  • nila

    its coming closest to our region!!! have there any possibility to harm our region???

  • cygo

    @jonisusilo Youngest? How do you figure that? I thought KBO’s were remnants of the of the proto-disc in which the planets formed. Ergo, parts of the oldest system material.

  • tfisher

    nila — it is only a shadow crossing your region. there is no possibility of harm from the shadow.

  • raisah

    tfisher is wont harm our country. silly

  • […] occultation of Pluto and its small moon Hydra. If you live in Southeast Asia and own a telescope, there’s still time for you to get involved in the project and collect data for the team!  […]

  • Brindha

    Hi Leslie! I’ll only be getting my 10″ telescope in early September. Can I still help with the observation in September? Please let me know if there is any way for me to help with this or any other project from down here in Malaysia.

  • Jubert Cabrezos

    i’ll try to observe hydra

  • […] Got a telescope and live in Southeast Asia? #NatGeo-funded astronomers need your help” i was already dreaming even before i fell asleep. this could have been my chance to be part […]

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