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,…

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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…

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Moving Mirrors at the Roque de los Muchachos

Putting the Galileo mirror onto the lorry
September 18, 2011

The big telescopes at the observatory at the Roque de Los Muchachos mostly use mirrors rather than lenses. Domestic mirrors have the aluminium behind glass to protect it, but astronomical mirrors have the aluminium on top. This gives the best image, but it also means that the aluminium slowly spoils, and has to be replaced every three years or so. This is not a simple operation. The aluminium layer is…

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