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Dark Energy Survey on BBC

November 1, 2011 By Leave a Comment
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The Cerro Tololo site in Chile, where the Dark Energy Survey will be carried out

The BBC website  ran a story a few days ago on the UK’s invovlement in the Dark Energy Survey, for which hardware is currently being assembled and tested in the lab where I spent my 3 1/2 PhD years, at University College London. The survey will be carried out with the 4-m Victor Blanco telescope at Cerro Tololo in Chile, using a dedicated new instrument, the Dark Energy Camera.

DECam will be placed at the telescope’s prime focus, above the telescope’s primary mirror. From this location, the camera will image huge swathes of sky with its wide 2 square degree field. To have access to such a large field, and to ensure great image quality over the full area, the camera needs an impressive set of 5 large lenses, up to almost 1 meter in size. In case you’re wondering, meter-sized science-grade lenses are very costly, and very challenging to produce.

In the full Dark Energy Survey, to be completed over 5 years from next September, the large international science team aims to image some 300 million galaxies in several filters, which will allow them to tackle the dark energy question on a number of fronts: by studying Type Ia supernovae, weak gravitational lensing, galaxy clustering, and the large scale distribution of galaxies on the sky to study baryonic acoustic oscillations.

The Optical Science Lab at UCL was just getting involved in this exciting project around the time I was finishing my PhD there, and the group is now working on the assembly and alignment of these lenses in the lab. It’s really great to see some coverage of this project and of UCL’s instrumentation work in the media. New science results are exciting, but all the technical work that makes them possible is just as fascinating.

 

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Expecting to Fly (Let’s Get On With It)

April 19, 2011 By Leave a Comment

JWST full scale model at NASA's Goddard Space Flight Institute (Image: NASA)

 

For 4 years, I’ve been a member of a team that will deliver part of the biggest ever astronomical space mission: the James Webb Space Telescope. In just a few weeks’ time, we’ll begin testing the flight hardware for MIRI, the telescope’s mid-infrared instrument, that will allow it to peer deeper into dense dusty and cold regions of our Galaxy and the Universe than its three fellow instruments. “Flight hardware” means that these are the actual bits and pieces that will be launched into space on board an Ariane rocket. Yes, that’s seriously cool.

My four years on the team makes MIRI my longest relationship in science yet. I’m rather fond of the little tyke. But four years is nothing in today’s era of mega-science. Literally hundreds of people have had a relationship with some part of the James Webb mission for well over a decade. Some may well be approaching their silver anniversary. Those of you with instrumentation experience know well what this means: meetings, documents, designs, documents, simulations, telecons, more meetings, reviews, procurement, manufacturing, testing, negotiations, documents, meetings. Endless, over and over.

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Exoplanets at a discount

September 7, 2010 By

Fig. 1: An image of Beta Pic's companion taken with the apodising phase plate on VLT/NaCo, after processing. The light from the central star was blocked out (in processing). Credit: ESO

ResearchBlogging.org
Astronomers have many ways of spotting exoplanets round far away stars – but getting a direct look at them, especially with ground-based telescopes, remains a difficult job. With a planet emitting very little light of its own, and appearing to us essentially on top of the host star, its radiation is completely drowned in the image of the star. Catching those few photons and separating them from the flood of light from the star requires some clever observational tricks. To do this with ground-based telescopes, we at the very least need adaptive optics, to prevent the atmosphere from creating a blurry mess and  keep the image nice and sharp, and often some sort of mask that will block out as much as possible of the stellar light. But an upgrade to one of ESO’s near-infrared workhorse imager NaCo on VLT’s 4th Unit Telescope has just made it a whole lot easier.

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Adventures in ELT Wonderland

August 26, 2009 By

Snazzy artist's rendering of the E-ELT, VLT and the Atomium

Optical and infrared observations are the bread and butter of astronomy. For thousands of years the earliest scientists were inspired by the light coming from the sun and the night sky, the light they could see with the unaided eye. These observations have shaped our vision of the world throughout history. Using modern telescopes we can see far beyond the wavelengths visible to the naked eye, catching the photons from the most distant known objects in the Universe, from radio waves through to the most energetic gamma rays. But it’s optical and infrared images, like those produced by the Hubble Space Telescope, that still prove the most inspiring to many scientists and the public.

For the past 2 years I’ve been involved in the planning of the next generation of optical/IR observatories, the European Extremely Large Telescope or E-ELT. Specifically, I work on the design of a potential instrument for this mammoth of a telescope, whose 42-m primary mirror diameter will be four times larger than the largest optical telescopes in the world today. Previous generations of telescopes have always seen an approximate doubling of mirror size, and this new generation of observatories signal an important departure from this trend – a hugely ambitious endeavour by all accounts.

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Unsung hero(in)es of astronomy

February 2, 2009 By

I spotted an interesting paper today in the optics journal Optics Express by astronomers Bland-Hawthorn and Kern, on astro-photonics. In the introductory paragraphs they write the following:

The unsung heroes of the inexorable march of astronomy are the instrument builders that place instruments at the telescope focus. The manipulation of faint light  requires a great deal of ingenuity if the instrument (e.g. spectrograph) is to achieve its theoretical limits within the hostile environment of a mountain-top observatory. The design and construction of the next generation of astronomical instruments presents us with an even bigger challenge. Simply scaling up existing technology leads to highly ineffective and costly instruments that are rarely optimized for the job at hand. The astronomical community must embrace new technological avenues.

It brought a tear, albeit proverbial, I was in the office, to my eye. Read the rest of the paper here.

Reference: Bland-Hawthorn & Kern, Astrophotonics: A new era for astronomical instrumentation, Optics Express vol. 17 no. 3, 1880-1884 (2009)

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