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This is Lowell Observatory.

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Lowell is one of many observatories

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around the world that will be observing the DART impact,

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NASA's first ever planetary defense test mission

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to see how much a spacecraft impact can deflect an asteroid in its orbit.

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This is where Pluto was discovered.

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And we are still doing research in all areas of astronomy today.

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So let's go check it out.

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This is the Pluto Telescope,

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the telescope that was used to discover Pluto almost a hundred years ago.

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So here we are at the Clark Telescope.

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This is where Percival Lowell sat to observe Mars.

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Let's head on over to the Lowell Discovery Telescope

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about an hour south of Flagstaff,

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which is where we are going to be collecting data for the DART mission.

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And the reason we're all the way out here

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in the middle of this forest is that we have really dark skies here.

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And this is the Lowell Discovery Telescope.

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This is what a 4.3 meter telescope looks like.

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This is what we will be using to study Didymos and Dimorphos

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in the days and weeks after DART impact.

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The DART spacecraft will be hitting an asteroid called Dimorphos.

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It's special because it's a binary asteroid,

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which means a satellite around a larger asteroid called Didymos.

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And DART will actually be hitting Dimorphos.

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And what we will be measuring is how much

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DART changes the orbit of Dimorphos around Didymos.

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So this is an important test for planetary defense mitigation strategies

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in case we ever have to do this for real.

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The Lowell Discovery Telescope is one of many telescopes around the world

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which will be used to study Didymos and Dimorphos.

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It's really a global, coordinated effort.

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And what we're looking at here is a large 4.3 meter primary mirror

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that's in the middle of the telescope tube here.

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Up at the top is a secondary mirror.

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The secondary mirror up top there is what is focusing the light down

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onto the instruments and allows us to take images

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with the camera that's located down at the bottom.

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This is maybe one of my favorite hidden rooms at the telescope.

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We're like standing inside the telescope, underneath the telescope.

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There's a hundred tons above your head held up by this and this, which is cool.

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It's sort of, as you can see, the highest peak around here, just over 8,000 feet.

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I come up here for sunset because you know, the sun setting right there.

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It's just, it's perfect.

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For DART, we're going to be collecting images of the night sky.

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And typically, an observer would be here in front of one of these consoles

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controlling the instrument and taking images

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like these as they're coming in off the telescope.

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DART is really a sort of before-and-after experiment.

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We need to understand the system before the spacecraft intentionally impacts.

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And then we have to understand what the outcome of that impact event is.

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As we watch from the Earth,

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Dimorphos will pass in front of Didymos and behind Didymos.

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What we will be doing with those images is measuring the brightness of Didymos

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in those images and looking at how that brightness changes

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and those dips in brightness allow us to measure when these eclipse

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happen and measure the orbit period of Dimorphos.

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And so you have essentially a fixed star field here.

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All the white dots are stars of different brightness

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and moving through this field is Didymos and Dimorphos,

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which, again, we can't distinguish them as discrete points of light,

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but we have that small object moving through the field of view.

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So after impact, we will then be able to go back and start

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observing intensely, looking for those mutual events,

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those eclipse events of Dimorphos passing in front of and behind Didymos.

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And on each one of these frames, we're measuring the brightness to assess

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whether or not it's undergoing one of these events where Dimorphos

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is passing in front of or behind.

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And using those to determine the orbit period of Dimorphos around Didymos.

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This is such a cool experiment and it's such a singular experiment.

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Using the ground-based telescopes like this one and others around the world

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to watch the system and see how it's affected by this impact event,

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because that's really what's going to give us the answer to

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what did DART do at the time of impact?

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And that will be exciting to see how that evolves over the days and