Giant 30 and 40 meter diameter ground telescopes will have 13 times more light collection than the best optical telescopes today and with 16 times the sharpness of hubble. This will enable a massive increase in the direct imaging of exoplanets.
Extremely Large Telescope 39 meter scope first light 2024
The Extremely Large Telescope (ELT) is an astronomical observatory and the world’s largest optical/near-infrared extremely large telescope now under construction. Part of the European Southern Observatory (ESO) agency, it is located on top of Cerro Armazones in the Atacama Desert of northern Chile. The design consists of a reflecting telescope with a 39.3 metres (130 feet) diameter segmented primary mirror and a 4.2 meter (14 ft) diameter secondary mirror, and will be supported by adaptive optics, eight laser guide star units and multiple large science instruments. The observatory aims to gather 100 million times more light than the human eye, 13 times more light than the largest optical telescopes existing in 2014, and be able to correct for atmospheric distortion. It has around 256 times the light gathering area of the Hubble Space Telescope and, according to the ELT’s specifications, would provide images 16 times sharper than those from Hubble. The first stone of the telescope was ceremonially laid on 26 May 2017 and started construction of the dome’s main structure and telescope. First light was planned for 2024.
Giant Magellan Telescope 24.5 meter equivalent scope first light 2023
The Giant Magellan Telescope (GMT) is a ground-based extremely large telescope under construction, planned for completion in 2025. It will consist of seven 8.4 meter (27.6 ft) diameter primary segments, that will observe optical and near infrared (320–25000 nm) light, with the resolving power of a 24.5 meter (80.4 ft) primary mirror and collecting area equivalent to a 22.0 m (72.2 ft) one, which is about 368 square meters. A total of seven primary mirrors are planned, but it will begin operation with four. The $1 billion project is US-led in partnership with Australia, Brazil, and South Korea, with Chile as the host country. First light is targeted for 2023.
Direct imaging with 30 meter class ground telescopes
Over the past three decades instruments on the ground and in space have discovered thousands of planets orbiting nearby stars. These observations have given rise to an astonishingly detailed picture of the demographics of short-period planets (less than 10 days), but are incomplete at longer periods where both the sensitivity of transit surveys and radial velocity signals plummet. Even more glaring is that the spectra of planets discovered with these indirect methods are often inaccessible (most RV and all microlensing detections) or only available for a small subclass of transiting planets. Direct detection, also known as direct imaging, is a method for discovering and characterizing the atmospheres of planets at intermediate and wide separations. It is the only means of obtaining spectra of non-transiting exoplanets. Today, only a handful of exoplanets have been directly imaged, and these represent a rare class of young, self-luminous super-Jupiters orbiting tens to hundreds of AU from their host stars. Characterizing the atmospheres of planets in the less than 5 AU regime, where RV surveys have revealed an abundance of other worlds, requires a 30-m-class aperture in combination with an advanced adaptive optics system, coronagraph, and suite of spectrometers and imagers – this concept underlies planned instruments for both TMT (the Planetary Systems Imager, or PSI) and the GMT (GMagAO-X). These instruments could provide astrometry, photometry, and spectroscopy of an unprecedented sample of rocky planets, ice giants, and gas giants. For the first time habitable zone exoplanets will become accessible to direct imaging, and these instruments have the potential to detect and characterize the innermost regions of nearby M-dwarf planetary systems in reflected light. High-resolution spectroscopy will not only illuminate the physics and chemistry of exo-atmospheres, but may also probe rocky, temperate worlds for signs of life in the form of atmospheric biomarkers (combinations of water, oxygen and other molecular species). By completing the census of non-transiting worlds at a range of separations from their host stars, these instruments will provide the final pieces to the puzzle of planetary demographics. This whitepaper explores the science goals of direct imaging on 30-m telescopes and the technology development needed to achieve them.