Beyond 6dF (what more can we do for you?)
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Transcript of Beyond 6dF (what more can we do for you?)
Beyond 6dF(what more can we do for you?)
Anna Moore
Roger Haynes
Will Saunders + BJB
Fibre Positioner for Subaru/FMOS– Piezo ball-spine– 400 fibres– 0.5deg diam.
• 150mm Pick-and-place
– 0.9-1.8m
– Feed FMOS spectrograph
Steel Ball
Magnets
Spine
Counterweight
Echidna Ball-Spine
Moduleassembly
Top bridge
Fibre cover
Middle bridge
Fibre spines and piezo actuators
Module PCB
Module base
Echidna complete design
Single module
Example of fibre allocation to randomly scattered targets
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7mm spine deviation
90% success rate for random targets
Applications for Echinda
Gemini wide-field MOS (GWiMOS)– 1.5deg2 at prime focus
• Corrector design exists (400kg)• 0.5arcsec images (1” fibres)• 1.4m corrector
– 4000 fibres• Echidna fibre positioner• Fibre-spacing compatible with Subaru
– 10 more fibres, 10 larger area
Gemini wide-field
• US$20M project– Initial design already begun (NOAO/AAO)
• Opportunity to use AAO funds (A$2.5M) – Committed over 2002-05 as part of successful
bid to Aus. Govt to increase Gemini share– Build prototype to address ‘high-risk’ areas
• addressing >1000 fibres• patrolling field/reconfiguring times
Build prototype for use on UK Schmidt
Prototype Concept
Positioner– 2250 spines (15 arcmin patrol area)
• Slight lower packing than Echidna (s’graph limited)
– 60mm diameter (4 arcsec) – <10% vignetting over full 6o f.o.v.– Spine Tip Imager: ‘single shot’ for full field
• 5min reconfiguration time
Spectrograph
Concept– Based on KOSMOS concept– Single-beam Schmidt-Schmidt spectrograph
• Collimator f/2.25• Camera f/1.3
– VPH grating: R=10000– 2 x 2k x 4k CCD – 3 slits (750 fibres each)
• 1st order 845-870nm (grat=0.9)
• 2nd order 422-435nm (grat=0.8)
Schmechidna
• Total cost A$4M– Spectrograph: A$1.5M– Positioner: A$2.5M
• Purpose designed for stellar work
• IAB=15.5 R=104 S/N=30 in 1200s (S/N for 2nd order)
– 30 mins/field (inc. overheads)– 60% clear– 2000 objects/field (not limited by stellar density)
22000 objects per night (average)
Options
Option A
• No upgrade to existing system
Option B
• 6dF full upgrade: – new field plates + new spectrograph
Option C
• Schmechinda
Cost/benefit analysis
A6dF
B6dF+
CSchmechidna
Instrumentation - $2M $4M(A$1.5M)
Operations (5yr) $3M $3M $3M
# stars* 5.5x105 1.2x106 4.0x107
A$/star 5.5 4.1 0.18t(107 stars) 91yr 42yr 1.25yr
$(107 stars) $273M $128M $5M
*Fields/clear night: 5 (A), 8 (B), 18 (C) Ids/field: 100(A), 135(B), 2000(C) Fraction clear: 60% Resolution: 4000 (A,B) 10000(C)
DIVA survey (accessible from Australia): done in ~3yr
Futher Issues
• Schmechidna: medium technical risk– Echidna spine module already working– patrol camera innovative
• AAO ‘in kind’ contribution: $2.5M– only $1.5M outstanding instrumentation costs
• Room to increase S/N or mag. limit
– 107 stars in 5 years (S/N 50 or Ilim 16)
Further issues
• Survey using Schmechidna start in 2005/6?• Minimum of 107 stars by 2007 2010
– depending on survey parameters
• N. hemisphere: Kisochidna/KOSMOS??– Double cost– Double number of objects– Cover whole sky
Schmechidna All New Stellar Survey for Orbits, Uelocities, and Chemical Indices