The National Science Foundation (NSF) has awarded Georgia State University a substantial grant of $1.39 million to enhance the Center for High Angular Resolution Astronomy (CHARA) Array at Mount Wilson Observatory in Southern California.
The CHARA Array consists of six synchronized telescopes, each with a one-meter diameter light-collecting mirror, spread across the mountaintop.
By combining light from these telescopes through a method known as interferometry, the array simulates the resolution capabilities of a telescope with a 300-meter light-collecting mirror, producing detailed astronomical images.
The planned upgrades include advanced optical equipment at the telescopes, improved controllers, and a sensitive star tracking detector camera.
With the enhancements expected to be completed by 2028, the facility aims to expand its capability to detect stars across both visible and near-infrared spectrums.
Gail Schaefer, Ph.D., has been the director of the CHARA Array since 2022 and was the associate director for three years prior.
She expressed enthusiasm for the upcoming discoveries enabled by these upgrades.
In previous collaborations with researchers from the University of Michigan, the University of Exeter in the United Kingdom, and the Université de la Côte d’Azur in France, there is anticipation that the enhancements will significantly benefit ongoing research efforts.
Schaefer mentioned, “[The researchers] have built these six telescope imaging combiners; some of [the combiners] work in the near-infrared and some of them in the visible wavelengths.
What we would like to do is collect data across the visible and near-infrared wavelengths simultaneously, and this new grant allows us to do that more easily than we currently do.”
This advancement will improve researchers’ understanding of star structures.
Observing the edges of a star introduces challenges, as the light diminishes — a phenomenon known as limb darkening, according to Schaefer.
“Being able to record different colors of light at the same time allows you to know the structure of the star really well,” she explained.
This capability is particularly vital when studying stars with exoplanets, where the planet may transit the star, blocking light and revealing information about the star’s surface characteristics.
Additionally, the ability to capture data at different wavelengths will facilitate the study of surface features, such as star spots — commonly referred to as sunspots.
Another significant enhancement will be the introduction of a new star tracking instrument, which will improve the capability to research fainter stars, thanks to the increased stability provided by the upgraded tracking system.
“The surface tracking camera basically just picks up part of the light and makes sure that the star stays centered on the science instrument,” Schaefer described.
Although CHARA shares similarities with a few other global facilities, such as the Very Large Telescope Interferometer (VLTI) in Chile, it remains unique due to its capabilities, particularly in terms of angular resolution.
The Navy Precision Optical Interferometer (NPOI) in Arizona and the recently expanded Magdalena Ridge Observatory also employ comparable techniques, yet CHARA’s focus on high angular resolution distinguishes it within the field.
CHARA embraces an open access policy, allowing researchers worldwide to apply for observing time, making it a valuable resource for astronomers.
“It’s a really unique facility to actually be able to see what stars actually look like, rather than just being pinpoints of light in the sky,” Schaefer emphasized, highlighting the importance of the array.
Since its inception in 1984, the CHARA Array has been significantly supported by NSF funding, which has been crucial for its development and operational success.
The idea for the CHARA array began with a commitment to “promoting, designing, funding and operating a major new instrument capable of achieving new levels of angular resolution,” according to the CHARA website.
The center received initial funding in 1985 for planning activities and additional funding for engineering studies in 1992.
In 1996, construction began on the array of five telescopes, supported by $5.6 million from the NSF, followed by an additional telescope added from the W.M. Keck Foundation in 1998.
By 2004, all six telescopes were operational and conducting routine scientific observations.
Over the years, NSF’s ongoing financial support has facilitated numerous discoveries, a continuity that Schaefer appreciates, particularly with the latest grant providing vital resources for advancing astronomical research.
“We’re absolutely thrilled this funding went through, and it’s a way to keep CHARA relevant and be able to do cutting-edge science that pushes the field forward,” Schaefer concluded.
image source from：saportareport
