Way Out West Texas: Eyes on the Skies

Way Out West Texas: Eyes on the Skies
Published: Jun. 16, 2023 at 10:26 AM CDT
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FAR WEST TEXAS (KOSA) - When studying the skies, telescopes are crucial and the Hobby-Eberly Telescope at the McDonald Observatory is the largest in North America. It is helping astronomers study dark energy in West Texas’ backyard.

Dark energy is known as a mysterious force that is causing the universe to expand faster as it ages. The Hobby-Eberly Telescope Dark Energy Experiment, or HETDEX, is a multi-year project that collects data on at least one million far-away galaxies to learn more about this unknown phenomenon.

“We just want to see how much the universe is expanding, so all that HETDEX has to do to study dark energy is to look at those distant galaxies and see how fast they’re moving towards or away from us,” said Steven Janowiecki, the HET science operations manager at the McDonald Observatory.

Astronomers measure the rate of expansion the same way they measure sound.

“We call it a Doppler shift, it works for sound, it works for light. When it’s coming towards you the frequency is a little higher and when it passes you the frequency goes down,” Janowiecki said.

HETDEX is looking at more distant galaxies which are from older parts of the universe, a task that most telescopes are not able to do. However, the use of the telescope goes beyond just the HETDEX. The telescope is also used to study spectroscopy.

“What we mean by spectroscopy is taking light and breaking it into a spectrum. You can think about it as when light goes through a prism and you see that rainbow on your wall in the background, but these rainbows are much more detailed and within them we can pull out specific data about different elements, understanding temperature, understanding how far away something is and really understanding the universe,” said Katie Kizziar, the assistant director for education and outreach at the McDonald Observatory.

The Hobby-Eberly Telescope was designed specifically for spectroscopy, this makes the telescope ideal for searching for planets, stars, distant galaxies and black holes.

It is also uniquely built with mirrors that are always tilted at 55 degrees above the horizon and a tracker mounted above that moves in six directions. This design allows the telescope to study 70 percent of the visible sky.

“A telescope is nothing more than a bucket, a bucket that collects light from the sky. So, as long as your bucket doesn’t have a hole in it, you can keep collecting light. As long as we keep our optics fresh it still collects light, that never changes. If we can keep the telescope functioning, we can still point at objects in the sky and keep collecting data,” said Teznie Pugh, the superintendent for the McDonald Observatory.

With 91 hexagonal mirrors on the 10-meter telescope, the HET is also the third largest optical telescope in the world. More importantly, it is incredibly designed to help astronomers continue to learn and make new discoveries about the night skies.

For more information about the Hobby-Eberly Telescope and how you can get involved in HETDEX visit the McDonald Observatory website.