GREETINGS FROM MISSION CONTROL by Derrick Rohl, Sudekum Planetarium Manager


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GREETINGS FROM MISSION CONTROL by Derrick Rohl, Sudekum Planetarium Manager

Greetings from “night 4” of our observing run. I put it in quotes because it’s actually only our second night of observing – the first two nights’ weather was too questionable to open the dome (dew on the telescope = bad). But on cloudy and clear nights alike, I’ve been busy getting photos! Take a look at life on the mountain:

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Me, holding a camera and pretending to know how it works. The neck strap around my elbow might suggest otherwise.


The 4.0-m telescope we’ll be using, referenced based on the diameter of its primary mirror, bottom center.

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Dr. French and I ogling at the primary mirror. For scale, I’m just over 6 feet tall.


One of the many control screens at our disposal. At left, the configuration of the Dark Energy Camera’s 62 detector chips. At right, an indication of sky conditions. The huge size of those circles is a sign of less-than-ideal seeing.


According to temperature readouts at the bottom right, the detector is kept around -100 degrees C. “That’s so cool,” I accidentally exclaimed at 5am last night.


Take a look at the top left. “Airmass” is how much air we’re looking through. Think to geometry class and 30/60/90 triangles. If we’re looking at an object 30 degrees above the horizon, we’re looking through twice as much air compared with looking directly up. As we followed our target across the sky, you can see how we looked through less air as it rose, then more as it set. Science.


Our fearless leader, David James, keeping us on track via video conference from La Serena. He was with us in person for the start of our run, but thanks to video conferencing, he can balance family time and work time.


And now, a look outside:


You can see the Milky Way over our telescope’s dome. The glow at the right is La Serena in the distance, the glow at the left is the rising moon.


This is the mountaintop lit only by moonlight. Alpha and Beta Centauri, along with the Southern Cross, are labeled for your educative enjoyment. Crux, the Southern Cross, is probably as well-known here as the Big Dipper is in the northern hemisphere. The big dipper isn’t visible here in Chile, just as Crux isn’t visible back home in Nashville. That’s that round earth at work!


With the Earth’s rotation over the course of a few hours, the stars appear to follow these trails. But remember, just like sunrise and sunset, it’s actually caused by the earth moving, not everything else in the sky.

For now, I’d better get back to observing! These asteroids aren’t going to take images of themselves.

Clear skies,

- Derrick Rohl, Sudekum Planetarium Manager

Posted by Derrick Rohl at 3:37 PM
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