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  • Writer's pictureMatt Russell

284 - Space Telescopes

Jazz is like a telescope, and a lot of other music is like a microscope.

Kamasi Washington

Linn tells Matt about her trip to ESO's Telescope facility in the Atacama Desert of northern Chile on Cerro Paranal at 2,635 m (8,645 ft) altitude, 120 km (70 mi) south of Antofagasta. By total light-collecting area, it is the largest optical-infrared observatory in the Southern Hemisphere

Linn also Interviews fellow astronomer James Miley in this bumper Telescope Podcast

James Miley

Is an astronomer and astrophysicist currently based in Santiago, Chile as an ALMA postdoctoral fellow at the Joint ALMA Observatory (JAO) and Project Research staff as part of NAOJ Chile.


His scientific research focuses on planet formation. He works to understand the link between the circumstellar discs of gas and dust that we observe around young stars, and the planets that form in these environments.





To be thought of as a science god you must be associated with a telescope. Galileo, Newton and Einstein are. ...here is s little history.
  • 1608 patent submitted to the government in the Netherlands by Middelburg spectacle maker Hans Lippershey for a refracting telescope (unlikely to be inventor, but said he saw some kids using two lenses to make things closer) x 3 magnification

  • 1609 news had spread to Galileo who set about making his own and got to x10 magnification - and BOOM modern astronomy was born and he became the first person to see the moons of Jupiter!!! Galileo Galilei was the first astronomer to view the Pleiades through a telescope too

  • Glass has loads of problems, if it gets too big it sags, and also the colours don’t bend at the same rate, hence rainbow colours through thick glass prisms ...see Pink Floyd's Dark Side of the moon cover. (spherical aberration and chromatic aberration)

  • People started thinking about using mirrors to get around this.

  • In 1668, Isaac Newton built the first practical reflecting telescope, the Newtonian.

  • The invention of the achromatic lens in 1733 sort of corrected colour aberrations,

  • Silver-coated glass mirrors in 1857 and aluminized mirrors in 1932 all meant that these telescopes were slowly being improved and getting better, but then we reached a limit which is roughly;

    • maximum physical size limit for refracting telescopes is about 1 meter (40 inches)

    • The largest single mirror refractor is 8.2m or 323 inches, like the Subaru in manukea and the VLT telescopes in Chile

  • But you can make bigger refractors by making them with multiple cell mirrors, like james webb etc, each of these cells has to be controlled by a computer in shape and position to keep the cluster in focus!!!!

  • So the 20th century has been dominated by reflectors, which are getting bigger thanks to a design using segmented mirrors

  • Largest at the moment is Gran Telescopio Canarias (GTC) in the canary islands at a whopping 10.2 metres or 409 inches

Future Telescopes

  • The Vera C. Rubin Observatory, previously referred to as the Large Synoptic Survey Telescope (LSST), an observatory currently under construction in Chile

  • Giant Magellan Telescope 7 × 8.4 m mirrors giving a 24.5 m aperture with 21.4 m light gathering area (first light planned in 2021 and completion in 2025


Linn's Trip To Paranal

The main facility at Paranal is the VLT, which consists of four nearly identical 8.2-metre (27 ft) unit telescopes (UTs), each hosting two or three instruments. These large telescopes can also work together in, groups of two or three, as a giant interferometer. The ESO Very Large Telescope Interferometer (VLTI) allows astronomers to see details up to 25 times finer than those seen with individual telescopes.


The light beams are combined in the VLTI with a complex system of mirrors in tunnels, where the light paths must diverge less than 1/1000 mm over 100 metres. The VLTI can achieve an angular resolution of milliarcseconds, equivalent to the ability to see the headlights of a car on the moon.


The first of the UTs had its first light in May 1998 and was offered to the astronomical community on 1 April 1999.


The other telescopes followed suit in 1999 and 2000, making the VLT fully operational. Four 1.8-metre auxiliary telescopes (ATs), installed between 2004 and 2007, have been added to the VLTI for accessibility when the UTs are used for other projects.


Data from the VLT have led to the publication of an average of more than one peer-reviewed scientific paper per day; in 2017, over 600 reviewed scientific papers were published based on VLT data. The VLT's scientific discoveries include imaging an extrasolar planet, tracking individual stars moving around the supermassive black hole at the centre of the Milky Way and observing the afterglow of the furthest known gamma-ray burst.


At the Paranal inauguration in March 1999, names of celestial objects in the Mapuche language were chosen to replace the technical designations of the four VLT Unit Telescopes (UT1–UT4). An essay contest was prior arranged for schoolchildren in the region concerning the meaning of these names which attracted many entries dealing with the cultural heritage of ESO's host country. A 17-year-old adolescent from Chuquicamata, near Calama, submitted the winning essay and was awarded an amateur telescope during the inauguration.[60] The four-unit telescopes, UT1, UT2, UT3 and UT4, are since known as Antu (sun), Kueyen (moon), Melipal (Southern Cross), and Yepun (Evening Star) with the latter having been originally mistranslated as "Sirius", instead of "Venus".[



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