Tag Archives: European Southern Observatory

Webb Space Telescope Provides an Extraordinary View of the Planet Neptune

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Peter Lobner

In April 2021, I posted a short article entitled, “Multi-messenger Astronomy Provides Extraordinary Views of Uranus,” which included two composite views of Uranus, created by combining near-infrared images taken by the Keck-1 telescope at an elevation of 4,145 meters (13,599 ft) on Maunakea, Hawaii, with X-ray images taken with the Advanced CCD Imaging Spectrometer (ACIS) aboard the orbiting Chandra X-Ray Observatory.

Now, the Webb Space Telescope has taken stunning near-infrared images of the next, and outermost, planet in our solar system, Neptune (sorry, Pluto). You can read NASA’s 21 September 2022 news release on these images here: https://www.nasa.gov/feature/goddard/2022/new-webb-image-captures-clearest-view-of-neptune-s-rings-in-decades

The Webb images of Neptune, taken on July 12, 2022, are reproduced below.

NASA: “Webb captured seven of Neptune’s 14 known moons: Galatea, Naiad, Thalassa, Despina, Proteus, Larissa, and Triton. Neptune’s large and unusual moon, Triton, dominates this Webb portrait of Neptune as a very bright point of light sporting the signature diffraction spikes seen in many of Webb’s images.”
Source: NASA, ESA, CSA, STScI
NASA: “…image of Neptune……brings the planet’s rings into full focus for the first time in more than three decades. The most prominent features of Neptune’s atmosphere in this image are a series of bright patches in the planet’s southern hemisphere that represent high-altitude methane-ice clouds. More subtly, a thin line of brightness circling the planet’s equator could be a visual signature of global atmospheric circulation that powers Neptune’s winds and storms. Additionally, for the first time, Webb has teased out a continuous band of high-latitude clouds surrounding a previously-known vortex at Neptune’s southern pole.” Source: NASA, ESA, CSA, STScI

The Space Telescope Science Institute (STScI) has created a Resource Gallery of Webb Space Telescope images, which you can browse here: https://webbtelescope.org/resource-gallery/images. Currently there are 280 images in the Webb Resource Gallery.  I think this is a website worth revisiting from time to time.

NASA’s Solar System Exploration website provides views of Neptune from several earlier sources, including the 1989 Voyager 2 deep space probe, the Hubble Space Telescope and the European Southern Observatory’s (ESO) Very Large Telescope (VLT). Check it out here: https://solarsystem.nasa.gov/planets/neptune/galleries/

2018: The following image was taken in July 2018 during the testing of the narrow-field, adaptive optics mode of the optical/infrared MUSE/GALACSI instrument on ESO’s VLT, which is located at an elevation of 2,635 m (8,645 ft) at Cerro Paranal, in the Atacama Desert of northern Chile.

2018 VLT image of Neptune. The corrected image is sharper than a comparable image from the NASA/ESA Hubble Space Telescope. Source: ESO/P. Weilbacher (AIP)

1994: The more recent Webb Space Telescope and VLT images are much better than the Hubble Space Telescope optical-range images of Neptune taken more than two decades earlier, in 1994.

NASA: “The images were taken in 1994 on October 10 (upper left), October 18 (upper right), and November 2 (lower center). Hubble is allowing astronomers to study Neptune’s dynamic atmosphere with a level of detail not possible since the 1989 flyby of the Voyager 2 space probe. Building on Voyager’s initial discoveries, Hubble is revealing that Neptune has a remarkably dynamic atmosphere that changes over just a few days. The temperature difference between Neptune’s strong internal heat source and its frigid cloud tops (-260 degrees Fahrenheit) might trigger instabilities in the atmosphere that drive these large-scale weather changes. In addition to hydrogen and helium, the main constituents, Neptune’s atmosphere is composed of methane and hydrocarbons, like ethane and acetylene.” Source: NASA, JPL, STScI

1989: In October 1989, the following whole planet view of Neptune was produced using images taken through the green and orange filters on the narrow angle camera during the Voyager 2 spacecraft flyby of the planet.

NASA: “This picture of Neptune was taken by Voyager 2 less than five days before the probe’s closest approach of the planet on Aug. 25, 1989. The picture shows the “Great Dark Spot” — a storm in Neptune’s atmosphere — and the bright, light-blue smudge of clouds that accompanies the storm”. 
Source: NASA/JPL-Caltech (1989)
 

In the future, we can hopefully look forward to more detailed multi-messenger images of Neptune, combining the near-infrared images from Webb with images from other observatories that can view the planet in different spectral bands.

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The Event Horizon Telescope Team has Produced the First Image Showing the Shadow of the Sgr A* Black Hole at the Center of our Milky Way Galaxy

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Peter Lobner

Background

The first-ever direct image of a black hole was released on 10 April 2019 by the Event Horizon Telescope (EHT) team and the National Science Foundation (NSF).  The target for their observation was the supermassive M87* black hole at the center of the distant Messier 87 (M87) galaxy, some 54 million light years away. The EHT team estimated that M87* has a mass of about 6.5 billion Solar-masses (6.5 billion times greater than the mass of our Sun), and the black hole consumes the equivalent of about 900 Earth-masses per day. One Solar mass is roughly equivalent to the weight of the Sun and about 333,000 times the mass of Earth. Gases orbiting around the giant M87* black hole take days to weeks to complete an orbit. For more information on the first M87* black hole image, see my 10 April 2019 article here: https://lynceans.org/all-posts/the-event-horizon-telescope-team-has-produced-the-first-image-showing-the-shadow-of-a-black-hole/

For decades, there has been mounting evidence that there is a massive black hole, known as Sagittarius A*, or Sgr A* for short, at the center of our Milky Way galaxy.  Its presence has been inferred from the motions of visible stars that are orbiting under the gravitational influence of the black hole or are in the general vicinity of the black hole.  Using observed data from more than 30 stars in the region around the galactic center, scientists developed high-resolution simulations that helped refine estimates of the location, mass and size of the Sgr A* black hole without having data from direct observations.  For more information on this work, see my 24 January 2017 article here: https://lynceans.org/all-posts/the-black-hole-at-our-galactic-center-is-revealed-through-animations/

First-ever image of Sgr A*

On 12 May 2022, the EHT team and the European Southern Observatory (ESO) held a press conference and released the first-ever image to directly show the ring of glowing gas surrounding the Sgr A* black hole.  You can read their press release here: https://eventhorizontelescope.org/blog/astronomers-reveal-first-image-black-hole-heart-our-galaxy

Initial EHT team and ESO results from their Sgr A* observations have been published and are available on The Astrophysical Journal Letters website here: https://iopscience.iop.org/journal/2041-8205/page/Focus_on_First_Sgr_A_Results

First-ever image looking down into the ring of rotating, glowing gas
surrounding Sgr A*. Source: EHT Collaboration
Composite image showing the location of the Sgr A* black hole (inset) in a composite 
X-ray/infrared NASA image of the heart of our Milky Way galaxy. 
Source: EHT Collaboration & NASA

Even though it was much closer than M87*, getting an image of Sgr A* was much harder because the Sgr A* black hole had to be viewed through the densely populated central plane of our Milky Way.  The Sgr A* radio frequency (millimeter wave) observations were made in 2017 at a wavelength of 1.3 mm (230 GHz), the same as the first image of M87*. 

Details that have emerged so far from the Sgr A* observation include the following.

  • Sgr A* is about 27,000 light years away, at the heart of our own galaxy (about 2 thousand times closer than M87*, which is in a different galaxy). 
  • Sgr A* has a mass is about 4 million times the mass of our Sun, which is just a small fraction (1/1,500th , or 0.07%) of the mass of M87*.
  • The glowing gas ring surrounding the Sgr A* black hole has an outer diameter of about 72 million miles (115 million km) across, which is approximately the diameter of Mercury’s orbit around the Sun in our solar system. The EHT team reported, “We were stunned by how well the size of the ring agreed with predictions from Einstein’s Theory of General Relativity.”  By comparison, M87* is vastly larger, with the inner black hole region measuring about 23.6 billion miles (38 billion km) across (about 330 times the diameter of the entire Sgr A* black hole, including the glowing gas ring), as shown in the following scale diagram.
Comparison of the sizes of M87* (left) and Sgr A* (right). 
Source: EHT Collaboration (acknowledgment: Lia Medeiros)
  • The two black holes subtend approximately the same angle when viewed from Earth. The EHT team reported that the M87* bright emission disk subtends an angle of 42 ± 3 microarcseconds.
  • Gases orbiting around the Sgr A* black hole take mere minutes to an 1 hour to complete an orbit.  The fast moving gases blur the image for an EHT observation typically lasting several hours. The released image of the Sgr A* black hole is an average of many different images the EHT team extracted from the data.
  • Sgr A* is far less active than M87*, and consumes only about 1/1,000th the mass per day (equivalent of about 1 Earth-mass per day).
  • The source of the three bright spots in the glowing gas ring are unknown at this time.  They may be artifacts of the EHT observation process.

Follow-on EHT observations will benefit from additional telescopes joining the EHT network and significant technical improvements being made to the EHT telescopes and network systems.  For example, operating the telescopes in the EHT array at a shorter wavelength of 0.87 mm (frequency of 345 GHz) will improve angular resolution by about 40%. More frequent observations and faster data processing would enable time-lapse movies to be created to show the dynamics of gas motion around the black hole. Details on planned improvements are discussed in my 9 April 2020 article here: https://lynceans.org/all-posts/working-toward-a-more-detailed-view-of-a-black-hole/

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The Black Hole at our Galactic Center is Revealed Through Animations

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Peter Lobner

Evidence is mounting that a supermassive black hole named Sagittarius A* (Sagittarius A star) dominates the center of our Milky Way galaxy. Long-term observations of the galactic center by teams of astronomers are refining our understanding of how stars move in relation to this unseen black hole.

European Southern Observatory (ESO) observations of the galactic center

The ESO, which has many observatories located high in the mountains of northern Chile, has a team involved in observing our galactic center. Two of the ESO optical observatories used in this effort are:

  • New Technology Telescope (NTT), at the La Silla Observatory, has a 3.58 m (11.75 ft) main mirror. In 1989, NTT became the first astronomical observatory with adaptive optics to help correct for atmospheric distortion.
  • Very Large Telescope (VLT), which consists of four Unit Telescopes with 8.2 m (26.9 ft) diameter main mirrors and adaptive optics. The telescopes can work together, to form a giant ‘interferometer’, allowing astronomers to see details up to 25 times finer than with the individual Unit Telescopes.

On 10 December 2008, ESO issued a “science release” entitled, ”Unprecedented 16-Year Long Study Tracks Stars Orbiting Milky Way Black Hole,” which summarized the results of observations made at NTT and VLT from 1992 to 2008. This study mapped the orbits of 30 stars in the region around the galactic center (and did not use VLT’s interferometric capabilities).

 Galactic center_eso0846aStars near our galactic center and the Sagittarius A* black hole. Source: eso0846 Science Release

The eso0846 science release is available at the following link:

http://www.eso.org/public/usa/news/eso0846/

In connection with this study, the ESO team also created a time-lapse video showing star motion around the Sagittarius A* black hole.

“Here, actual images, collected over the past 16 years, have been assembled into a time-lapse video. The real motion of the stars has been accelerated by a factor 32 million.”

This time-lapse video covers the central part of the above color image of the galactic center and shows stars moving around central point that is likely to be the black hole. You can see this animated sequence at the following link:

http://www.eso.org/public/usa/videos/eso0846j/

UCLA Galactic Center Group observations of the galactic center

The mission statement of the UCLA Galactic Center Group is:

“Transforming our understanding of Black Holes and their role in the Universe with high resolution observations of the Center of our Galaxy!”

The Galactic Center Group’s website is a good source of information on black hole science and the technologies employed to observe our galactic center. Their home page is at the following link:

http://www.galacticcenter.astro.ucla.edu/about.html

The W.M. Keck Observatory on Mauna Kea in Hawaii is comprised of two large telescopes, each with 10 m (33 ft) main mirrors and adaptive optics. Currently the Keck Observatory has the largest optical / infrared telescopes in the world. These telescopes have higher resolution than ESO’s NTT and VLT.

Using images taken at the Keck Observatory from 1995 to 2014, the UCLA Galactic Center Group and the W.M. Keck Observatory Laser Team have released their determination of the orbits of stars within the central 1.0 X 1.0 arcseconds of our galaxy, as shown in the following diagram.

UCLA-Keck-2014

The team reported:

“These orbits provide the best evidence yet for a supermassive black hole. While every star in this image has been observed to move since 1998, estimates of orbital parameters are best constrained for stars that have been observed through at least one turning point of their orbits.”

This makes the star S0-2 especially important because it has been observed for more than one full orbital period, which for S0-2 is only 16.17 years. The team estimates that the Sagittarius A* black hole has a mass of 4 million times the mass of the Sun.

The UCLA Galactic Center Group and the W.M. Keck Observatory Laser Team have created a series of animations that demonstrate the motion of stars near the Sagittarius A* black hole. You can navigate to these animations from the home page listed above or use the following direct link:

http://www.galacticcenter.astro.ucla.edu/animations.html

The three animations showing star motions around the Sagittarius A* black hole are:

  • Animation of the Stellar Orbits around the Galactic Center
  • 3D Movie of Stellar Orbits in the Central Parsec
  • Sagittarius A* – IR (infrared)

The importance of adaptive optics is astronomical observations is demonstrated in another animation from the UCLA Galactic Center Group.

“This animation shows observations of the Galactic Center with and without adaptive optics, illustrating the resolution gain. Adaptive optics corrects for the blurring effects of the Earth’s atmosphere. Using a bright star, we measure how a wavefront of light is distorted by the atmosphere and quickly adjust the shape of a deformable mirror to remove these distortions.”

Screenshots from this animation are shown below. The screenshot on the left is with adaptive optics OFF. The image on the right is with adaptive optics ON.

Adaptive optics OFF  Adaptive optics ON

The future

In my 6 June 2015 post, “Three Very Large, New Optical Telescopes are Under Development,” I reported on the Thirty Meter Telescope (TMT), which originally was planned for construction on Mauna Kea, near the Keck Observatory. As the name implies, TMT will have a 30 m (98.4 ft) main mirror and adaptive optics. To illustrate the improved resolution of TMT, the UCLA Galactic Center Group developed an animation showing Sagittarius A* images for the following three cases:

  • Keck telescopes with current adaptive optics (AO)
  • Keck telescopes with “next generation” adaptive optics (NGAO), and
  • The future TMT with adaptive optics.

As you can see in the following screenshot from this animation, the expected results from the much higher resolution TMT quite impressive.

Relative resolution power - Keck & TMT

TMT’s actual construction site is being reconsidered and construction has been delayed. However, ESO has broken ground for the even larger European Extremely Large Telescope (E-ELT), which is being built now at Cerro Armazones, Chile. This giant telescope has a 39 m (128 ft) main mirror and adaptive optics. It will become the largest optical / infrared telescope in the world when it is commissioned as part of ESO’s Paranal Observatory in 2024. Hopefully, time on this great telescope will be allocated to observing our galactic center.

Atacama Large Millimeter / submillimeter Array (ALMA) Provides a Unique Window on the Universe

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Peter Lobner

The Atacama Large Millimeter / submillimeter Array (ALMA) is a single telescope composed of 66 high-precision, 12-meter antennas. ALMA operates at wavelengths of 0.3 to 9.6 millimeters. As shown in the following chart, this puts ALMAs observing range around the boundary between microwave and infrared.

wavelength-spectrum1Source: physics.tutorvista.com

This enables ALMA’s users to examine “cold” regions of the universe, which are optically dark but radiate brightly in the millimeter / submillimeter portions of the electromagnetic spectrum. In that frequency range, ALMA is a complete astronomical imaging and spectroscopic instrument with a resolution better than the Hubble Space Telescope.

The ALMA Array Operations Site (AOS) is located on the Chajnantor plateau (which in the local Atacameño language, Kunza, means “place of departure”), at an elevation of about 5,000 meters (16,400 feet) above sea level in northern Chile.

ALMA_AOSView of the AOS. Source: ESO

On 30 September 2013 the last of the 66 antennas, each of which weighs more than 100 tons, was delivered to the AOS on the giant transporter named Otto (one of two available for the task) and handed over to the ALMA Observatory. The 12 meter antennas have reconfigurable baselines ranging from 15 meters to 18 km. Depending on what is being observed, the transporters can move ALMA antennas to establish the desired array. The transporters carry power generators to maintain the cryogenic systems needed to ensure that the antenna continues functioning during transport.

ALMA_antenna on transporterSource: ESOalma_antennas_nrao04bSource: ESO

ALMA is managed by an international partnership  of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan, together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile.

The ALMA telescope is operated from the Operations Support Facilities (OSF), which is located at a considerable distance from the telescope at an elevation of about 2,900 meters (9,500 feet). The OSF also served as the Assembly, Integration, Verification, and Commissioning (AIVC) station for all the antennas and other high technology equipment before they were moved to the AOS.

The ALMA website is at the following link:

http://www.almaobservatory.org

You’ll find many downloadable ALMA-related documents on the Publications tab of this website. A good overview of the ALMA telescope and the design of the individual antennas is available at:

http://www.almaobservatory.org/images/pdfs/alma_brochure_explore_2007.pdf

ALMA press releases, with details of on many of interesting observations being made at the observatory are at the following link:

http://www.almaobservatory.org/en/press-room/press-releases

An example of the type of remarkable observations being made with ALMA is in the 16 July 2016 press release, “ALMA Observes First Protoplanetary Water Snow Line Thanks to Stellar Outburst.”

“This line marks where the temperature in the disk surrounding a young star drops sufficiently low for snow to form. A dramatic increase in the brightness of the young star V883 Orionis flash heated the inner portion of the disk, pushing the water snow line out to a far greater distance than is normal for a protostar, and making it possible to observe it for the first time.”

ALMA was looking in the right place at the right time. An artist’s impression of the water-snow line around V883 Orionis is shown in the ESO image below.

eso1626aCredit: A. Angelich (NRAO/AUI/NSF)/ALMA (ESO/NAOJ/NRAO)

You can read this ALMA press release and view a short video simulation of the event at the following link:

http://www.eso.org/public/usa/news/eso1626/

No doubt ALMA’s unique capabilities will continue to expand our knowledge of the universe in the millimeter / submillimeter portions of the electromagnetic spectrum. In collaboration with great land-based and space-based observatories operating in other portions of the spectrum, ALMA will help create a more comprehensive understanding of our universe. See my 6 March 2016 post, “Remarkable Multispectral View of Our Milky Way Galaxy,” to see how different a portion of the night sky can look in different portions of the electromagnetic spectrum.

Remarkable Multispectral View of Our Milky Way Galaxy

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Peter Lobner, updated 18 August 2023

Moody Blues cover - In search of the lost chordAlbum Album cover art credit: Deram Records

Some of you may recall the following lyrics from the 1968 Moody Blues song, “The Word,” by Graeme, Edge, from the album “In Search of the Lost Chord”:

This garden universe vibrates complete

Some, we get a sound so sweet

 Vibrations reach on up to become light

And then through gamma, out of sight

Between the eyes and ears there lie

The sounds of color and the light of a sigh

And to hear the sun, what a thing to believe

But it’s all around if we could but perceive

 To know ultraviolet, infrared and X-rays

Beauty to find in so many ways

On 24 February 2016, the European Southern Observatory (ESO) Consortium announced that it has completed the ATLASGAL Survey of the Milky Way. The survey mapped the entire galactic plane visible from the southern hemisphere at sub-millimeter wavelengths, between infrared light and radio waves, using the Atacama Pathfinder EXperiment (APEX) telescope located at 5,100 meters (16,732 ft.) above sea level in Chile’s Atacama region. The southern sky is particularly important because it includes the galactic center of our Milky Way. The Milky Way in the northern sky has already been mapped by the James Clerk Maxwell Telescope, which is a sub-millimeter wavelength telescope at the Mauna Kea Observatory in Hawaii.

The new ATLASGAL maps cover an area of sky 140 degrees long and 3 degrees wide. ESO stated that these are the sharpest maps yet made, and they complement those from other land-based and space-based observatories. The principal space-based observatories are the following:

  • European Space Agency’s (ESA) Plank satellite: Mission on-going, mapping anisotropies of the cosmic microwave background at microwave and infrared frequencies.
  • ESA’s Herschel Space Observatory: Mission on-going, conducting sky surveys in the far-infrared and sub-millimeter frequencies.
  • National Aeronautics and Space Administration (NASA) Spitzer Space Telescope: Mission on-going, conducting infrared observations and mapping as described in my 1 April 2015 post.
  • NASA’s Hubble Space Telescope: Mission on-going, observing and mapping at ultraviolet, optical, and infrared frequencies.
  • NASA’s Chandra X-Ray Observatory: Mission on-going, observing and mapping X-ray sources.
  • NASA’s Compton Gamma Ray Observatory: Mission ended in 2000. Observed and mapped gamma ray and x-ray sources.

ESO reported that the combination of Planck and APEX data allowed astronomers to detect emission spread over a larger area of sky and to estimate from it the fraction of dense gas in the inner galaxy. The ATLASGAL data were also used to create a complete census of cold and massive clouds where new generations of stars are forming.

You can read the ESO press release at the following link:

https://www.eso.org/public/news/eso1606/

Below is a composite ESO photograph that shows the same central region of the Milky Way observed at different wavelengths.

ESO Multispectral view of Milky WaySource: ESO/ATLASGAL consortium/NASA/GLIMPSE consortium/VVV Survey/ESA/Planck/D. Minniti/S. Guisard. Acknowledgement: Ignacio Toledo, Martin Kornmesser

  • The top panel shows compact sources of sub-millimeter radiation detected by APEX as part of the ATLASGAL survey, combined with complementary data from ESA’s Planck satellite, to capture more extended features.
  • The second panel shows the same region as seen in shorter, infrared wavelengths by the NASA Spitzer Space Telescope
  • The third panel shows the same part of sky again at even shorter wavelengths, the near-infrared, as seen by ESO’s VISTA infrared survey telescope at the Paranal Observatory in Chile. Regions appearing as dark dust tendrils in the third panel show up brightly in the ATLASGAL view (top panel).
  • The bottom panel shows the more familiar view in visible light, where most of the more distant structures are hidden from view

NASA’s Goddard Space Flight Center also  created a multispectral view of the Milky Way, which  is shown in the following composite photograph of the same central region of the Milky Way observed at different wavelengths.

NASA Goddard multispectralSource: NASA Goddard Space Flight Center

Starting from the top, the ten panels in the NASA image cover the following wavelengths.

  • Radio frequency (408 MHz)
  • Atomic hydrogen
  • Radio frequency (2.5 GHz)
  • Molecular hydrogen
  • Infrared
  • Mid-infrared
  • Near-infrared
  • Optical
  • X-ray
  • Gamma ray

The Moody Blues song, “The Word,” ends with the following lyrics:

 Two notes of the chord, that’s our full scope

But to reach the chord is our life’s hope

And to name the chord is important to some

So they give it a word, and the word is “Om”

While “Om” (pronounced or hummed “ahh-ummmm”) traditionally is a sacred mantra of Hindu, Jain and Buddhist religions, it also may be the mantra of astronomers as they unravel new secrets of the Milky Way and, more broadly, the Universe. I suspect that completing the ATLASGAL Survey of the Milky Way was an “Om” moment for the many participants in the ESO Consortium effort.

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Three Very Large New Optical Telescopes are Under Development

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Peter Lobner

Giant Magellan Telescope (GMT), Las Campanas Observatory, Chile

The GMT is a new, very large optical telescope facility planned for construction at an elevation of over 2,550 m (about 8,500 ft) in the mountains of the Chilean Atacama Desert. The GMT is comprised of seven 8.4 m (27 ft) diameter monolithic, circular mirror segments arranged in a hexagonal array. GMT will have a total optical surface measuring 24.5 m (80 ft) in diameter, with an optical surface area of 368 square meters (3,860.8 square feet). The GMT is expected to have 10 times the the resolving power of the Hubble Space Telescope.

image  Source: www.gmto.org

GMT will be the largest optical telescope in the world when it sees first light in 2021. It is expected to be fully operational in 2024. For more details, including a 360 degree tour, check out the GMT website at the following link:

http://www.gmto.org/overview/

On 3 June 2015, the international consortium known as Giant Magellan Telescope Organization (GMTO), approved proceeding to the construction phase. You can read this press release at the following link:

http://www.gmto.org/2015/06/giant-magellan-telescopes-international-partners-approve-start-of-construction-phase/

European Extremely Large Telescope (E-ELT), Cerro Armazones, Chile

The E-ELT program was approved in December 2012, and groundbreaking for the new observatory occurred in January 2014 in the Chilean Atacama Desert.  When it is completed, E-ELT will be the largest optical / infrared telescope in the world.  Its 39 meter adaptive mirror, composed of about 800 hexagonal segments, will be able to adjust the alignment of individual mirror segments a thousand times a second.

EELTSource: eelt.orgEELT2Source: eelt.org

Detailed information on EELT is available on the European Southern Observatory (ESO) and E-ELT websites at the following links:

https://www.eso.org/sci/facilities/eelt/

and

http://www.eelt.org.uk

Thirty Meter Telescope (TMT), Mauna Kea, Hawaii, USA

The TMT is a new, very large optical telescope facility planned for construction on Mauna Kea, at an elevation above 3,960 m (about 13,000 ft). The TMT will be a wide-field telescope with a 492 segment, 30 meter (98.4 ft) diameter primary mirror, a fully-active secondary mirror and an articulated tertiary mirror. The telescope is designed for flexibility in the choice of adaptive optics (AO) systems and science instruments that can be used for specific observations. TMT will have a light-collecting area of 664.2 square meters (7,148.7 square feet), almost 10 times more than one of the 10 m (32.8 ft) diameter Keck telescopes (also on Mauna Kea), with diffraction-limited spatial resolution that exceeds Keck by a factor of 3. Relative to the Hubble Space Telescope, TMT will have more than a factor of 10 better spatial resolution at near-infrared and longer wavelengths. When completed, the TMT will take over the title of the world’s largest optical telescope from the GMT.

The general arrangement of the TMT, including the segmented primary mirror, is shown in the following diagram.

imageSource: UH, TMT.org

For more details on the TMT, visit the University of Hawaii’s website at the following link:

http://www.tmt.org

Particularly interesting is the Detailed Science Case: 2015 for the TMT, which you can find at the following link:

http://www.tmt.org/sites/default/files/TMT-DSC-2015-release-2015Apr29-s.pdf

The future of the TMT and other observatories on Mauna Kea is being discussed now by University of Hawaii, the Hawaii Governor’s office and native Hawaiian groups that have been protesting the presence of observatories on the mountain. On 1 June 2015, University of Hawaii issued a press release announcing it’s Implementation Plan for Improved Stewardship of Mauna Kea, with a commitment to provide additional details in July 2015. You can read this Plan at the following link:

http://www.tmt.org/news-center/uh-implementation-plan-improved-stewardship-maunakea

I hope that there is a place for the TMT on Mauna Kea.

16 October 2016 Updates:  TMT siting still not confirmed

New hearings on the future siting of TMT on Mauna Kea begin in Hawaii on 18 October 2016.  As a hedge against failing to gain approval in Hawaii, the TMT partners are considering alternate sites, including sites originally considered in the mid-2000s when TMT site selection started. An alternate site in the northern hemisphere is preferred because the two other giant optical / infrared telescopes, the GMT and E-ELT, already are under construction in the southern hemisphere.  Candidate sites in the northern hemisphere include:  San Pedro Martir in Baja California, Mexico and Roque de los Muchachos on the Spanish island of La Palma off the Atlantic coast of Morocco.