The Largest Ground-Based Telescope

The Large Binocular Telescope Surpasses Hubble Space Imaging

Aug 11, 2009

Astronomers have been interested in producing earth-based images that are as good as the Hubble space telescope. Now the Large Binocular Telescope does that.

For years NASA has been interested in making earth-based telescopes as good as the Hubble space telescope, i.e., they want the image to be as good as the one produced from space where there is no atmospheric interference. The University of Arizona, partnered with universities in Italy, Germany, and Ohio State University is now going in that direction with the use of large binocular telescope.

Large Binocular Telescope (LBT)

The Large Binocular Telescope in Arizona is the largest land-based telescope on earth. The project began in early 1994 and construction was completed in 2007. It has 2 - 8.4 meter mirrors that act as one. It has the equivalent light-gathering capacity of a single 11.8-meter scope and a resolving power capacity of a 22.8-meter telescope. This telescope will be able to resolve faint astronomical images currently possible only through the use of the Hubble telescope. This technological advance is possible because fast computers adaptive optics and the latest sensors provide the means for correcting atmospheric distortions and blurring while at the same time significantly improving image sharpness to 10 times and beyond the resolution capability of the Hubble telescope.

For example, as the earth rotates, sensors automatically modify the mirror's direction to keep it perpendicular to the angle of the incoming light source. Automatic corrections to atmospheric anomalies are also made possible because one of these corrections comes from the use of interferometers and nulling.

Interferometers and the Nulling Process

Using multiple mirrors in synchronized combination to gather light is interferometry. To build a picture with enough resolution the interferometer rotates around to different relative positions and repeats the "exposures." In addition to light gathering capabilities, an interferometer can obtain other electro-magnetic spectra of the targets it is looking at.

But the true power of interferometers comes from the nulling process. By nulling, telescopes can provide very good angular resolution and they can sort out which light haves come from which part of the star system. The interferometer can adjust the incoming light field so that light coming from the exact center of the star will be blanked out or nulled, while the light from any other area will be viewed normally. So instead of having an image that is obscured by glare, the image is fine tuned and the glare removed.

Astronomical Observations

With advanced optics and computer baseline systems, the LBT will be able to detect planets the size of Jupiter from the ground using a candidate field of the 50 nearest stars. The planet/background contrast will be improved more when using the interferometric mode, which will add to the number of candidate stars and making the survey larger and more sensitive.

The advance in ground based telescopic imaging that even surpasses Hubble telescope imaging will give many astronomers an additional tool in the study of deep space astronomy. The low cost of such devices, when compared to space based astronomy will allow them to plan for building additional telescopes.

Large Binocular Telescope

Interferometers and the Nulling Process

http://adsabs.harvard.edu/abs/2008A&A...490..435Dhttp://process-equipment.globalspec.com/LearnMore/Manufacturing_Process_Equipment/Inspection_Tools_Instruments/Interferometers

www.mpg.de/english/illustrationsDocumentation/documentation/pressReleases/2005/pressRelease20051026/index.html

The copyright of the article The Largest Ground-Based Telescope in Stargazing is owned by George Garza. Permission to republish The Largest Ground-Based Telescope in print or online must be granted by the author in writing.

Aug 12, 2009 12:51 AM

Guest :

I wonder what the limit is? How much and how deeply will we ever be able to see? And, how available will this be for the regular guy who wants to look at the stars? Ultimately, most of us will make do with <a href="http://www.telescopebinoculars.com/index.php?cPath=6">as tronomy binoculars</a> which will let us peek into the cosmos, and know there is much more we don't see.