Large Binocular Telescope Achieves First Light

After eight and a half years in the making, the Large Binocular Telescope (LBT) is finally ready to begin operation. Yesterday, it unveiled its first image (shown above), the target of which was Beta Pictoris.

The LBT gains its name from its twin 8.4 meter mirrors. While such large mirrors are impressive in their own right, the ability to use them in tandem is what gives the telescope its true power. By placing two mirrors far apart and combining the images, it allows astronomers to improve the resolution as if the mirror was effectively the width of the distance between the mirrors. According to Tom McMahon of the University of Arizona, Tucson and the project manager for the telescope, “Together, the two mirrors form the largest single-mount telescope in the world.”

Although this technique can improve resolution, the total light gathering power is still the same as the mirrors together. Additionally, to pull off this combining of images, known as interferometry, astronomers must carefully process the light from each mirror. The device in charge of collecting and making sense of the data is the Large Binocular Telescope Interferometer (LBTI). Its construction was begun in 2002 and is designed to “explore the regions surrounding nearby star systems for dust and planets”. To achieve this, the LBTI is intended to study the infrared portion of the spectrum in which dust and planets would glow the most strongly.

While the LBT has unprecedented resolving power, it is still not capable of finding Earth sized planet. According to the project’s website, the smallest planets the telescope can expect to discover are around two times the mass of Jupiter. Smaller ones would likely not emit strongly enough and be lost in the glare from their parent star.

On larger scales, the LBTI will be suited for studying of star formation in the Milky Way as well as other, nearby galaxies. Further out, the instrument can be employed to study Ultra Luminous Infrared Galaxies (ULRIGs) and Active Galactic Nuclei (AGN).

With this first image, the team responsible for the telescope and instrument are excited. But already, the LBT is slated for upgrades to the adaptive optics systems which will take much of the next year to install and test. Still, the telescope will be usable for some science during this time. As McMahon stated, “It’s taken time to make sure it works as envisioned, but now it’s time to do science.”