Realuminizing GTC’s tertiary mirror

The light path on a KECK telescope
June 29, 2012

  Modern telescopes have mirrors made of a material called vitro ceramic, which keeps its size and shape in spite of changes in temperature, covered with a very thin layer of aluminium. Domestic mirrors have glass in front of the aluminium, to protect it, but that means that the light passes through the glass twice – coming and going – which degrades the image. So telescope mirrors have the aluminium…


A birthday present for the William Herschel Telescope

The William Herschel Telescope at sunset, Roque de los Muchachos observatory
June 1, 2012

  The William Herschel Telescope is 25 years old today – first light was the 1st June 1987. For many years the Herschel was the biggest optical and infrared telescope in Europe, until Gran Telescopio Canarias opened in 2009. It’s main mirror is 4.2 m or 165? across which was huge when it opened, although that’s medium-sized these days. The telescope has so many different instruments that it’s been compared…


Inside the HARPS-N spectrograph

The big defraction grating on its zerodur support, HARPS-N spectrograph, Galileo telescope
May 21, 2012

  Francesco Pepe invited me to see inside the HARPS spectrograph. I was very lucky, because the enclosure was closed for the inauguration, and closed again (probably for years) soon after I took these photos. Of course I had to wear special over-clothes to prevent dust getting into the instrument. The top photo shows the grating, which splits the starlight into a rainbow, and the bottom one shows the collimator,…


Inauguration of the Liverpool Annex

The Liverpool Telescope, open at sunset, Roque de Los Muchachos observatory
May 3, 2012

  Today they inaugurated the annex building to the Liverpool telescope. The Liverpool is the joint largest robotic telescope in the world, with a 2 m mirror. Since there’s nobody at the telescope at night, it was built with very little in the way of workshops. But the new building contains a workshop to assemble and test new instruments, and a control room, to help humans commission them. Of course…


A Special Spectrograph.

The Telescopio Nazionale Galileo, late afternoon, Roque de Los Muchachos, La Palma
April 16, 2012

The Italian National Telescope (the Galileo) is getting a new scientific instrument to look for planets outside our solar system. I remember a childhood astronomy book which said that we would never know whether there are planets outside our own solar system, because they are much, much too small and much much much too far away. That’s all changed in the last few years. There’s a class of instruments called…