Dinner at the Drones

On Friday afternoon I gave a talk to the Royal Astronomical Society on big astronomical surveys and the sociological changes they are driving.. It pluggged UKIRT/UKIDSS, WFAU and CASU, and AstroGrid. I am proud to report these are all STFC Band 4 projects !! Woo hee. Keep going guys. The talk involved a live demo of both the WFCAM Science Archive and AstroGrid and went really well. (Many thanks to Mike Read, Mark Holliman, and Nigel Hambly for last minute server kicking.)

During the day there was a specialist meeting on the 42m Extremely Large Telescope (ELT), with fine opening reviews by Jason Pyromaniac and Captain Hook. Of course this used to be the 100m Overwhelmingly Large Telescope (OWL). I look forward to the day (2009 ?) when it gets descoped to 25m and renamed the FBT (Fairly Big Telescope). Some of the science cases are starting to look rather groovy. My favourite is the proposed CODEX instrument, which would take high resolution spectra of distant quasars. All been done before, you say ? Ah yes but they claim that over a period of twenty years, we should be able to see the Lyman-alpha forest move … i.e. we will actually directly detect the expansion of the Universe. Corr.

After my talk I got invited to the RAS Dining Club. Many years ago when I was a student I assumed the Dining Club was a sort of Astronomical Freemason thing – a secret club within the club where all the decisions got taken. Maybe that was true then, but it sure ain’t now, as about two thirds of the membership is retired anyway. It was like finding myself in a PG Wodehouse story. Dinner was at the Athenaeum, where somebody had to find me a tie. Luckily the Club keeps an emergency tie in a special wooden box. Conversation was deafening and at the end every guest had to tell a funny story. I felt sure that at any moment we would all start throwing bread rolls at Catsmeat Potter-Pirbright.

I didn’t tell the gorilla joke.

9 Responses to Dinner at the Drones

  1. Michael Merrifield says:

    I had always thought that the direct imaging of earth-ish extra-solar planets was the killer science case for the E-ELT, but am coming around to the idea that measuring changes in velocities of the Ly-alpha forest at the cm/s level is even more astounding.

  2. Vinay says:

    Oh no no, you would no throw a crumpet in the Athenaeum than you would at the Junior Ganymede. Such frivolities are reserved for the Drones or the Pelicans 🙂

    CODEX is mind-boggling. Detecting a 10 cm/s change over 10 years requires an extraordinarily stable and well-calibrated instrument.

  3. Peter Williams says:

    What’s the gorilla joke?

  4. KOMbat17 says:

    Surely building a 10cm/s precision velocity machine for 4xVLTs makes (a lot) more financial sense, yields a quicker science return and carries less technical risk than spending >1000M on a preposterously large telescope?

    The arguments for ELT *have* to be made on the basis of AO-derived resolution. On any other grounds, building more VLTs and better instruments will yield better science for our buck.

    Makes a change not to be calling for heads to roll, but it appears I’m an entirely negative individual on any topic!

  5. KOMbat17 says:

    P.S. I’m surprised they don’t issue you with a zimmer frame as well as a tie 🙂

  6. Michael Merrifield says:

    Well, four VLTs would get you the collecting area of a 16m telescope. To match up to a 42m telescope, you would need 25 VLTs. And 25 ultra-stable ultra-high-resolution spectrographs. Or maybe you could combine the light from all 25 telescopes into a single instrument. But you would want to minimize the light losses due to extra mirrors, so you would want to build your 25 8m telescopes very close together. Or maybe just combine them into one 40m telescope.

    Indeed, one of the arguments of an ELT has to be getting the benefits of its unprecedented resolution, but there is no harm in also pointing out that you can do amazing science that just needs a very big light bucket, like ultra-high-resolution spectroscopy of the ly-alpha forest to measure the expansion of the Universe directly.

  7. KOMbat17 says:

    Fair points. Does the case require the collecting area of 25 VLTs though? Combining the beams from the VLTs (which they’re planning for ESPRESSO, which probably has half an eye on this science case) is likely to be easier than phasing the segments of an ELT, plus you could “get going” on the 20 year baseline a decade earlier.

    Billion-Euro projects need so-called “killer applications”. This case is exciting, but is it one of them? With a passionate sponsor, might it be done earlier and cheaper with existing infrastructure? Those are the questions I’d be asking if I paid tax (God forbid).

  8. andyxl says:

    Pete – re the Gorilla joke, if I told you I would be blackballed

  9. Fitzwho? says:

    Codex will be wonderful, but the technology for 1cm/sec precision is almost here. See the Nature paper by Li et al. Nature 452, 610. It’s already being built for the HARPS-NEF spectrograph planned for the WHT in 2009-2010, see http://www.ing.iac.es/PR/press/astrocomb.html
    Your limit is photon noise – as always, dammit.

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