A1258690108OIgVp

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The OWL and the penguin
Why we should build an Extremely Large Telescope
in Antarctica
John W.V. Storey
Images Michael Ashley GSMT project
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A wise thought from the owl Sometimes its
easier to do two hard things than one hard thing.
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Outline

• You cant be serious...
• Orientation
• What makes a good observing site
• Additional requirements of an ELT
• Sub-millimetre thoughts
• The real disadvantages challenges
• Why Australia should do this
• The way forward

Image Patrik Kaufmann
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Top four myths about Antarctica

1. Its completely inaccessible
2. Your telescope will blow away
3. The conditions make it impossible to work
4. The polar bears will eat you

Image Karim Agabi
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Image Australian Antarctic Division
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ESO data
Valenziano DallOglio 1999, PASA 16, 167 Dome C
50 1.0 m/s
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Myth 3 The conditions make it impossible to
work....
Dome C. Pressure altitude 3600 m temperature
-30oC
Image Patrik Kaufmann
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Image Camillo Calvaresi
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Image Camillo Calvaresi
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Image Camillo Calvaresi
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Image Karim Agabi
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Image Geanpiero Venturi
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Image Camillo Calvaresi
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Image John Storey
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Orientation
Image Patrik Kaufmann
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Antarctica is very large

• USGS image

Geosciences Australia image
roughly twice the area of Australia.
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Contour map of Antarctica
Mount Kosciusko 2,228 m

• USGS image

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Potential observatory sites

• Dome A

• South Pole

• Vostok

• Dome C

• USGS image

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Dome C is a French/Italian station that will be
open year-round from 2005
Dome C

• Mawson

• Davis

• Casey

• Hobart

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Image Australian Antarctic Division
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South Pole Station South Pole Station Dome Concordia
Latitude Latitude 90º S 75º 06 S
Longitude Longitude - 123º 06 E
Altitude (m asl) Altitude (m asl) 2,835 3,205
Average pressure (mb) Average pressure (mb) 680 644
Minimum Temperature (ºC) Minimum Temperature (ºC) -82 -87
Average Temperature (ºC) Average Temperature (ºC) -49 -50.7
Average wind speed (m s-1) Average wind speed (m s-1) 5.8 2.8
Period of activity Period of activity Since 1957 Summer since 1997 Expected first winter-over 2005
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What makes a goodobserving site?

• Cloud-free
• High
• Dry
• Cold
• Dark, and radio-quiet
• Low integrated turbulence
• Low high-altitude turbulence
• Low wind at all altitudes
• Accessible

Image Karim Agabi
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Icecam and COBBER two micro-power instruments
to measure cloud cover.
Image John Storey
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Icecam
COBBER
The two experiments require no heat, run on a
lithium battery pack, and send data out via the
ARGOS satellite network.
Image John Storey
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ICECAM
Calibration LED
First winter-time stellar observations from Dome C
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ICECAM
Winter-time 2001 at Dome C data look encouraging!
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Clouds
2003 Icecam and COBBER data
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Aircraft contrails across Europe
http//www.eso.org/gen-fac/pubs/astclim/contrails/
NOAA-AVHRR-trail.jpg
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http//www.lightpollution.it/dmsp/
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The infrared sky is extremely dark

• Kdark sky spectral brightness
• 220 ?Jy. arcsec-2 (mean)
• 120 ?Jy. arcsec-2 (median)
• This is 1-2 orders of magnitude lower than found
  at typical mid-latitude sites

Lawrence et al, PASA (2002)
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South Pole is 20 100 times darker than Siding
Spring
Phillips et al 1999
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Mid-infrared Comparison between South Pole and
other sites
Chamberlain et al 2000
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This would be a good place
Image NASA
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Wind Speed Profiles (University of Nice)
Altitude (Km)
Altitude (Km)
Altitude (Km)
Dome C (Dec 2000)
Paranal ESO Chile (1992)
Gemini NOAO Chile (1998)
Agabi and Fossat (2003)
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Atmospheric turbulence
MK
The absence of high-altitude turbulence above the
Antarctic plateau is of profound
importance. Marks et al, AA Supp
(1998) Marks et al, AA Supp (1999)
SP
SP25
Log Altitude
Turbulence
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The effect of eliminating high-altitude turbulence
Turbulent layer high ? narrow field
Turbulent layer low ? wide field
10 100 times improvement in isoplanatic angle,
scintillation noise, and astrometric error.
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The effect of reducing high-altitude wind
Turbulent layer moves slowly

• Phase coherence times increased
• Required adaptive optics bandwidth decreases

10 100 times improvement in sensitivity of
interferometers and AO sensors.
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Sample SODAR data
900 m 0
June 24 - 27, 2000
Vertical wind speed
Wind direction
Horizontal wind speed
CT2
Time
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Summary of the global oceanic aerosol pattern
detected by polar-orbiting satellites between
July 1989 and June 1991

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Movie European Southern Observatory
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Additional requirements for ELTs
Image Patrik Kaufmann
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A Nest for OWL

• Additional Requirements for ELTs
• Low Seismic Activity
• An ELT cannot be made stiff enough to survive
  earthquakes
• Low Wind at ground level
• An ELT is more sensitive to wind shake during
  tracking
• Low Wind at high altitude
• Longer atmospheric time constant for AO
• Climate Stability

Marc Sarazin, ESO
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Peak Ground Acceleration up to 5m/s² 10
probability of exceedance in 50 years
Source http//www.seismo.ethz.ch/GSHAP/
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ESO data
Valenziano DallOglio 1999, PASA 16, 167
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Sub-millimetre thoughts
Image Patrik Kaufmann
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CARA has carried out very successful mm and
sub-mm work at South Pole for over a decade.
Image Tony Stark
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Quartiles of PWV at three Sites
At each site, the year is divided into the best
and worst 6 -month periods. Bars show quartiles
of the PWV distribution at each site.
Lane, ASP Conference Series 141, 1998
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Sky Noise and opacity measurements at 350µm from
three sites
Peterson, Radford et al (in press).
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Summer 2000 01 at Dome C South PoleOpacity
at 350 mm
Calisse et al 2003, PASA (submitted).
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Summary of site conditions
Low surface wind Low wind throughout
atmosphere No high level turbulence Low seismic
activity Very accessible Continuous observing
possible Stable climate
Clear High Dry Cold Clean Dark
Image Patrik Kaufmann
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SPIREX, the South Pole Infrared Explorer, was a
60 cm telescope with 1024 x 1024 InSb detector
array. SPIREX demonstrated the viability of IR
astronomy from Antarctica. SPIREX was a
collaboration between CARA, Ohio State
University, NOAO, Rochester I.T. and UNSW.
Image UNSW
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SPIREX image of star- formation in NGC6334
Burton et al, Astrophysical Journal, 542, 359,
(2000)
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The real disadvantages and challenges

• Diamond dust
• Altitude
• Winter isolation

• See less of sky
• Less true dark time
• Aurora?
• Ecliptic always at low elevation

Image Michael Ashley
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Why Australia should do this
Image Patrik Kaufmann
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Astronomy is one of the sciences in which
Australias international reputation is highest

• Over 160 professional astronomers employed at
  universities, observatories and CSIRO
• Citation rates amongst the highest in Australian
  science
• Nine astronomers amongst top 33 citation
  laureates
• Several world-class observatories in Australia
• International links to top institutions

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World class facilities in Australia include
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However, our Southern Hemisphere natural
advantage has been eroded.

• Australia has only a 5 share of Gemini (?
  6.5?).
• We have no high mountains. All future major
  developments in IR/optical astronomy will be
  off-shore.
• We have no sub-mm or far-infrared (THz)
  capability.

Radioastronomy may have a rosier outlook,
particularly if LOFAR and/or the SKA is built in
Australia.
Image ATNF
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Australia is uniquely placed to benefit from
Antarctic astronomy.

• Geographic proximity.
• Tradition of Antarctic exploration.
• On-going, major, national Antarctic program.
• No national participation in SOFIA, SIRTF etc.
• The Antarctic advantage means cutting edge
  science can be done at an affordable price.
• Experience with SPIREX/Abu and site testing
  demonstrates technological leadership.

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Logistic support of Dome C is via Hobart.
Image John Storey
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LAstrolabe brings heavy items from Hobart to
Dumont dUrville in 6 days...
Image John Storey
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...thence by tractor-traverse to Dome C.
Image Patrik Kaufmann
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The tractor-traverse takes 11 days to get from
the coast to Dome C.

• Three traverses/year (currently)
• Each traverse delivers 150 tonnes
• Fuel consumption 600 litres/tonne
• Twelve-metre sleds essentially no size or
  weight restrictions

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Dome C is particularly attractive to Australia
(compared to South Pole) because

• The logistic support is via Tasmania
• Dome C is at a similar longitude to the ATNF CA,
  Mopra, and AAT.
• Geostationary satellite communications are
  possible (eg AUSSAT?)

Image Karim Agabi
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The way forward

• Completion of site testing
• The DMT

Image Patrik Kaufmann
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The AASTINO at Dome C, 2003
Image Camillo Calvaresi
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The AASTINO
Instrumentation (on roof)
Solar panels
Heat exchangers
Electronics and work area
Iridium antenna
Stirling engines
1200 litre fuel tanks
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Image John Storey
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Image Geanpiero Venturi
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Image Geanpiero Venturi
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Image Camillo Calvaresi
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Image Camillo Calvaresi
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Image UNSW AASTINO webcam
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The AASTINO has operated robotically, without
human presence, since February 7, 2003.
Image Camillo Calvaresi
Image UNSW AASTINO webcam
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14 May, 2003. Images spaced every 30 mins.
Image UNSW AASTINO webcam
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SODAR
Image Geanpiero Venturi
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SODAR data
South Pole 2001
Dome C 2003 (so far...)
Travouillon et al, in prep.
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SUb MilliMetre Tipper (SUMMIT)

• Differential flux measurement at 350 ?m
• Calibrated to hot and cold blackbodies
• Opacity and brightness temperature
• Dome C summer 2000/2001
• South Pole winter 2001 2002

Image UNSW
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Opacity (tau) at 350 mm
Calisse et al, in prep.
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MASS Multi-Aperture Scintillation Sensor

• Sensitive measurement of the vertical
  distribution of turbulence
• A collaboration between CTIO, JPL and UNSW
• To be deployed to Dome C November 2003

Image Andrei Tokovinin
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The Douglas Mawson Telescope

• A 2-metre infrared telescope for Dome C.
• Proposed to MNRF II as an Australian/French/Itali
  an collaboration in 2001.
• Not funded in that round, but support is still
  strong from all partners.
• Important to find new funding options soon.

Image EOST
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Conclusions
Conditions at Dome C are unique, and extremely
favourable. A medium-size telescope or
interferometer could do ground-breaking
science. A very large telescope at Dome C would
be unbeatable. The opportunity awaits!
Image Patrik Kaufmann
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Myth 4 the polar bears will eat you
To deal with the polar bears, we pour water on
the ground... ...which freezes into
ice... ...and all the bears fall over.
Image www.dandennis.com
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Acknowledgements
IPEV - Institut Polaire Emile Victor ARC -
Australian Research Council NSF- National
Science Foundation AAD - Australian Antarctic
Division
JACARA - Joint Australian Centre for
Astrophysical Research in Antarctica Italian
Programma Nazionale di Ricerche in
Antartide CARA - Center for Astrophysical
Research in Antarctica
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IAU2003 General AssemblySydney, July 13 26
2003

• Special Session 2, ASTRONOMY IN ANTARCTICA, July
  18
• Future Visions for Antarctic Astronomy, Taronga
  Zoo, July 19

Michael Ashley Michael Burton Paolo
Calisse Jessica Dempsey Jon Everett Jon
Lawrence Caroline Santamaria John Storey Tony
Travouillon