Imaging Extrasolar Planets: with the European Extremely Large Telescope

Imaging Extrasolar Planets:  with the European Extremely Large Telescope

There is, in the pipeline, a new and even larger ground-based optical telescope known as the E-ELT, (European Extra Large Telescope), for short.   It is to be built in Cerro Armazones, Chile near the Paranal Observatory; just 20Km from the existing VLT (Very Large Telescope).   The planned completion date of the E-ELT, if all goes to plan, is sometime in 2022.  The E-ELT general specifications are as follows:

Organisation: European Southern Observatory (ESO)

Altitude:  3,060 metres

Weather: 89% clear fraction 0.67"median seeing @ 500nm

Wavelength: Visible light ~ Near Infrared range.

Instrument type: Optical Reflector

Mirror Diameter: 39.3 m (segmented primary) a new unique 5 mirror design; each mirror can distort its shape 1000 times per second to correct the image for atmospheric distortions, a system known as adaptive optics.

Angle of arc:  0.0001 to 0.65 arcseconds

Collecting area: 978 m2

Focal Length:  420-840m (f/10 ~ f/20)

Dome:  86 metres in diameter, half the size of a football stadium.

Website:  ESO E-ELT

The initial designs had planned to create a mirror with a 42-metre mirror area.  But, because of inherent design problems, this was reduced to 39.3 metres, which saved 220 million euros, reduced the cost to 1.055 billion euros, and shortened the project time to just 10years.

The E-ELT will be the worlds largest eye on the sky. Its light-gathering potential will be 15 times greater than that of any existing telescope.  It will produce images 15 times sharper than those provided by the Hubble space telescope and is planned to enable astronomers to probe the planetary systems around local stars in the Milky Way galaxy, and in addition, stars still in their formative stages.   It will be a giant leap forward in space exploration that will help astrobiologists detect water,   organic molecules, and possibly atmosphere on extrasolar planets orbiting other stars.  Other targets will be proto-planetary disks circling young stars, with planets in the making.  In addition, it will allow us to study distant gas giants like Jupiter and Saturn in greater detail. 

Ultimately E-ELT will probe deeper into the universe, looking at even more distant objects, chasing answers to the big questions.  This will include detailed studies of the most distant objects, and possibly measure the speed at which the universe is still expanding.

    Comparison with other large Earthbound telescopes:

                                  Name              Aperture Diameter  Collecting Area    State of Play

    Gran Telescopio Canarias  (GTC)            10.4m              74 m2    Largest currently in service 

    Keck Telescopes                                  10.0m              76 m2    Currently in service

    South'n African Large Telescope (SALT) 11.1 x 9.8m     79 m2   Due at end of the decade 

    Giant Magellan Telescope (GMT)            24.5m           368 m2    Due at end of the decade

    Thirty Meter Telescope (TMT)                 30.0m           655 m2    Due at end of the decade

    European Extremely Large Telescope  (E-ELT)

                                                             39.3m           978 m2    Due 2022  

 E-ELT's suite of instruments will help with investigating how objects form and evolve.   Identifying variations in physical constants with time.   The unambiguous detection of variations will advance the understanding of the laws of physics as we know them.

There are additional scientific instruments, adjuncts to the E-ELT, the aim is to switch from one instrument to another in moments, and move the dome rapidly to start a new observation in minutes

 Eight different instruments are planned:

CODEX:  A narrow field optical spectrograph (it separates incoming waves into a frequency spectrum ~ generated via a Fournier transform).

EAGLE:  A wide-field multi-channel integral-field near-infrared (NIR) spectrograph with multi-objective adaptive optics.

EPICS:  An optical/NIR planet imager and spectrograph with extreme adaptive optics.

HARMONI:  A single field, wide-band integral field spectrograph.

METIS:  A mid-infrared imager & spectrograph.

MICADO:  A diffraction-limited near-infrared camera (An optical system with the ability to produce images with angular resolution).

OPTIMOS:  A wide-field visual multi-object spectrograph.

SIMPLE:  A high-spectral-resolution NIR spectrograph.

The two post-focal adaptive optics modules currently being studied are:

ATLAS:  a laser tomography adaptive optics module.

MAORY: A multi-conjugate adaptive optics module.

The inception of the E-ELT project was rooted in the first decade of the 2000's. At that time a number of similar projects were on the drawing board.   The GTC, SALT, GMT, TMT, they are all due to come online before the end of this current decade.   You may wonder if the E-ELT is overkill?   But, the Astronomical community are close-knit and plan ahead with a lot of international cooperation.   Each project is planned to fill a niche in the search for further knowledge about the universe.   Each complex fulfils a need in that scientific community.   Science is a truly multinational fraternity, why else would a consortium of nations invest 1.055 billion euros setting up a telescope array in another country, such as Chile and call it a European telescope?   Surely this should point out the path to be followed by the Nations of this world.   That working together is the only logical way for humanity to progress.

The visible universe is no more than 5% of what is out there, the rest is made up of Dark Energy 72%, and Dark Matter 23%:

https://www.youtube.com/watch?v=gHium3r7qco

The time of discovery is not at an end, it is just beginning...