Uploaded January 2010 | Updated September 2026, 2 weeks ago
facebook.com/ScienceReason ... ESOcast 13: A sharper view of the Universe with the VLT Interferometer.
In principle, the larger a telescopes mirror, the finer the details it can see. Continuing to increase the size of telescope mirrors is not an easy task, so astronomers have come up with a new technology to see even finer details: interferometry.
This observational technique combines the light received by two or more telescopes and allows them to act as a single unit with a mirror diameter equivalent to the distance between the telescopes.
Engineers designed the VLT so that it can also be used as an interferometer. Along with the four 8.2-metre Unit Telescopes, four mobile 1.8-metre Auxiliary Telescopes (ATs) were included in the overall VLT concept to form the Very Large Telescope Interferometer (VLTI).
The ATs can move between 30 different stations, and at present, the telescopes can form groups of two or three for interferometry.
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Imagine looking up at the night sky and seeing details on the surface of a star millions of millions of kilometres away. Imagine having eyesight so keen that you could check out the surroundings of a black hole. Using ESOs Very Large Telescope Interferometer at Paranal, astronomers are now making these fantasies a reality.
Each of the four VLT Unit Telescopes has a primary mirror with a diameter of 8.2 metres. Such big mirrors are necessary because they collect more light and provide sharper images. Under ideal conditions and with the appropriate technology, the individual VLT Unit Telescope can see details of objects in space that are equivalent to viewing from here a tennis ball on the International Space Station, which is about 350 km above the ground.
This may sound like a really impressive number, but astronomers don't stop there. As frontline research requires studying the heavens in ever-increasing detail, new ways have had to be found to sharpen the VLT's already eagle-eyed vision even further.
And this is where interferometry comes in. Interferometry combines the light received by two or more telescopes that are simultaneously observing the same object. This allows astronomers to pick out details as sharply as if observing with a single telescope whose mirror has a diameter equivalent to the largest distance between the telescopes.
The VLT design always had the use of interferometry very much in mind. The four 8.2-metre Unit Telescopes of the VLT were built in a roughly trapezoidal configuration that can generate a virtual telescope mirror of up to 140 metres across.
In addition, four, movable, 1.8-metre Auxiliary Telescopes can be combined in a configuration with an equivalent diameter of up to 200 metres. This gives images up to 25 times sharper than those from a single VLT Unit Telescope.
Combining the light of different telescopes is a major technical challenge that requires almost unbelievable precision. The light beams from each telescope have to pass underground through a complex system of mirrors and delay lines before they are combined at the common focus.
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ESOcast is produced by ESO, the European Southern Observatory. ESO is the pre-eminent intergovernmental science and technology organisation in astronomy designing, constructing and operating the worlds most advanced ground-based telescopes.
• eso.org
.
facebook.com/ScienceReason ... ESOcast 13: A sharper view of the Universe with the VLT Interferometer.
In principle, the larger a telescopes mirror, the finer the details it can see. Continuing to increase the size of telescope mirrors is not an easy task, so astronomers have come up with a new technology to see even finer details: interferometry.
This observational technique combines the light received by two or more telescopes and allows them to act as a single unit with a mirror diameter equivalent to the distance between the telescopes.
Engineers designed the VLT so that it can also be used as an interferometer. Along with the four 8.2-metre Unit Telescopes, four mobile 1.8-metre Auxiliary Telescopes (ATs) were included in the overall VLT concept to form the Very Large Telescope Interferometer (VLTI).
The ATs can move between 30 different stations, and at present, the telescopes can form groups of two or three for interferometry.
---
Please SUBSCRIBE to Science & Reason:
• youtube.com/Best0fScience
• youtube.com/ScienceTV
• youtube.com/FFreeThinker
---
Imagine looking up at the night sky and seeing details on the surface of a star millions of millions of kilometres away. Imagine having eyesight so keen that you could check out the surroundings of a black hole. Using ESOs Very Large Telescope Interferometer at Paranal, astronomers are now making these fantasies a reality.
Each of the four VLT Unit Telescopes has a primary mirror with a diameter of 8.2 metres. Such big mirrors are necessary because they collect more light and provide sharper images. Under ideal conditions and with the appropriate technology, the individual VLT Unit Telescope can see details of objects in space that are equivalent to viewing from here a tennis ball on the International Space Station, which is about 350 km above the ground.
This may sound like a really impressive number, but astronomers don't stop there. As frontline research requires studying the heavens in ever-increasing detail, new ways have had to be found to sharpen the VLT's already eagle-eyed vision even further.
And this is where interferometry comes in. Interferometry combines the light received by two or more telescopes that are simultaneously observing the same object. This allows astronomers to pick out details as sharply as if observing with a single telescope whose mirror has a diameter equivalent to the largest distance between the telescopes.
The VLT design always had the use of interferometry very much in mind. The four 8.2-metre Unit Telescopes of the VLT were built in a roughly trapezoidal configuration that can generate a virtual telescope mirror of up to 140 metres across.
In addition, four, movable, 1.8-metre Auxiliary Telescopes can be combined in a configuration with an equivalent diameter of up to 200 metres. This gives images up to 25 times sharper than those from a single VLT Unit Telescope.
Combining the light of different telescopes is a major technical challenge that requires almost unbelievable precision. The light beams from each telescope have to pass underground through a complex system of mirrors and delay lines before they are combined at the common focus.
---
ESOcast is produced by ESO, the European Southern Observatory. ESO is the pre-eminent intergovernmental science and technology organisation in astronomy designing, constructing and operating the worlds most advanced ground-based telescopes.
• eso.org
.
