Robotic Telescopes
David Carter, Astrophysics Research Institute,
Liverpool John Moores University
Robotic Telescopes
David Carter, Astrophysics Research Institute,
Liverpool John Moores University
Aims of talk
1) Rationale and science goals of robotic
telescopes and telescope networks
2) Brief and very incomplete review of robotic
telescope projects worldwide
3) Report on the status and initial science results
from the Liverpool Telescope.
4) Will concentrate on optical/IR telescopes
Why robotic?
• Scientific Reasons
– Monitoring of variable objects on range of time-scales
– Rapid (and painless!) response (<1 minute) to transient targets.
– Flexible scheduling to take best advantage of all weather
conditions.
– Observing efficiency for diverse programmes
– Can be networked (eSTAR, ROBONET etc…)
• Operational Reasons
– Reduce operational costs
– Remove observer travel
– Telescope locations sometimes hostile.
– Increase Data Homogeneity (data pipelining, quality control,
archiving etc…)
Requirements for an automatic telescope?
• Automated startup and shut down
procedure.
• Very reliable weather information.
• Well defined sequence of observations
including calibration observations.
• High degree of reliability in your
telescope.
• Fault recovery/logging/management
procedures.
• Failsafe operation
• Autonomous scheduler for robotic
operation
Two classes of robotic Telescopes
• Survey telescopes (SuperWASP, Pan-STARRS)
– Wide field detectors, search for unexpected
phenomena
• Target of Opportunity/Monitoring telescopes
(REM, TSU, Stella I/II, LT, KAIT)
– Target of opportunity followup of discoveries made
elsewhere e.g. space based.
– Regular observations of known time variable
phenomena.
Science with Robotic Survey Telescopes
• Transient objects
– GRB Orphan afterglows
– Supernovae
• Moving objects
– Asteroids
– Comets
• Unpredictable variable phenomena
– Microlensing or transits (e.g. planet search)
– Variable phenomena in stars.
BAIT/KAIT
• Berkeley supernova search
telescopes
• Image nearby galaxies every night
• Automated detection of
supernovae
SuperWASP
• UK Consortium (Queens Belfast, Leicester, St.
Andrews, Cambridge, Keele, Open University, ING)
• Search for planetary transits
La Palma site for first
instrument
Second scheduled for
South Africa next year
Pan-STARRS
• University of Hawaii/Lincoln Labs.
• US Air Force funding.
• 4 x 1.8 metre telescopes each with 109 pixel CCD
mosaic
• 3 degree square field of view, 0.3 arcsec pixels.
• 30 second exposures.
• Survey whole sky 3 times/month.
• Main project is earth threatening asteroids and comets.
• Many other science applications (exoplanets,
supernovae, GRBs, variable stars, AGNs, large scale
structure).
Pan-STARRS
• First light for first telescope January 2006.
• Full array 2008
Science with Robotic Monitoring telescopes
• Target of Opportunity followup
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GRBs
Extragalactic Supernovae
Novae
Solar system objects
• Regular monitoring
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CVs
Young Stellar Objects
AGN and Quasars
Doppler mapping with a spectroscopic capability
Macro lenses
Pixel microlensing
Solar system objects
REM
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60 cm GRB followup telescope at La Silla
Very rapid slew speed
Large Italian consortium
Imaging + ROSS slitless spectrograph
Tennessee State University
• 2 metre spectroscopic robotic
telescope
• Arizona site (Fairborn Observatory)
• High dispersion fibre fed echelle
• Variable star work (CVs etc)
University of Indiana
• 1.3 metre spectroscopic
telescope
• High resolution echelle.
• 40cm photometric telescope
• Variable star work (CVs,
Novae).
Magnum
• University of Tokyo owned 2
metre telescope on Maui
• Principal science case is
monitoring of AGNs.
• Distance determination from
optical and UV variability.
Stella1/Stella2
• Potsdam/IAC project on
Tenerife
• Fully unattended operation
• Echelle spectroscopy plus CCD
imaging photometry
• Focus on cool stars –
monitoring activity tracers
• Commissioning end 2004
IRAIT
• Italian Robotic Antarctic
Infrared Telescope
• Regione Umbria / Perugia
University
• 80cm IR optimised telescope
• Tested in Coloti Observatory
• Move to Antarctica in 2006/7
Liverpool and Faulkes Telescopes
• 2 metre robotic telescopes (La Palma (LT), Maui (FTN)
and Coonabarabran (FTS))
• LT is primarily science, FTS and FTN education (but
each has a smaller rôle in the other activity).
• CCD imaging telescopes, but will have other
instruments.
• Science priorities of LT are monitoring and ToO
(Novae, CVs, SNe, GRBs, AGN, macrolensing,
microlensing).
Science with robotic telescope networks
• Transient phenomena which might occur at any time
– GRBs
– Supernovae
– Flares (e.g. dwarf novae).
• Occasions where round the clock coverage is important
– Microlensing including pixel microlensing
– Irregular stellar or AGN variability
– Doppler tomography
ROTSE
• University of Michigan/Los Alamos/UNSW project
• GRB followup (prompt flashes) and variable stars
• CCD imaging telescopes
ROTSE I
• ROTSE I made the first discovery of GRB prompt
optical flash (GRB990123)
ROTSE III
• ROTSE III 4 x 45cm telescopes (Turkey, Texas,
Namibia, Australia)
• Rapid slew and acceleration 35 deg/s; 16 deg/s2
• Horizon to horizon slew in 8 seconds.
• 1.85 degree field of view
Robonet
• UK Consortium proposal for six 2 metre telescopes
Funded only at prototype level so far
Robonet-1.0
• Prototype proposal
• 2.5 year project
• PPARC funded purchase of time on Faulkes
telescopes
• Incorporate Liverpool Telescope
Robonet-1.0
Robonet key science projects
• GRB (SWIFT) followup – early detection and
monitoring of optical counterparts of GRBs
• Microlensing search for planets.
eStar
Iain Steele, Chris Mottram, Jason Etherton (JMU); Tim
Naylor, Alasdair Allen (Exeter)
Liverpool Telescope performance
and first results
Enclosure report
• Enclosure Hydraulics Upgrade (Hydraul-Syd,
Elan-El).
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Proportional control of each ram
Position feedback loop from each corner.
Safe, reliable, robotically controllable operation
Commissioned July 2004
LT Specifications
• 2m primary (f/3), f/10 at Cass
• Alt-Az (hydrostatic bearings)
• Image quality < 0·4’’ on-axis
• Pointing < 2” rms
• Closed loop tracking < 0·2’’
over 1hr
• Max slew rate > 2° per sec
• Zenith blind spot < 2°
• Robotic (unmanned) operation with
automated scheduler
• First light July 2003
• Science Operations Jan 2004
Instrumentation
Iain Steele, Chris Mottram, Alan Scott (JMU)
John Meaburn, Dan Harman (Manchester)
Phil Charles, Luisa Morales (Southampton)
Sue Worswick (Optical design), Bob Leach (CCD
controllers)
RATCAM CCD Camera
• 2048 x 2048 pixels
• FoV 4·6 x 4·6 arcmin
• Cooled to 163K
• Readout < 10 sec
• Completed
V =20 (SNR = 10) in 2 sec
SupIRCam (with ICSTM)
• 256 x 256 HgCdTl array
• F.O.V. 1·7 x 1·7 arcmin
• 1 – 2·5 microns
• JH(K’) filters
• Cooled to 77K
• J ~ 15 in 1 minute
• Mechanically installed
• Commissioning in September
Spectrographs
Prototype:
• PPARC-funded fibre-fed prototype (with Manchester)
• 3500 < λ < 7000A, R ~ 1000 (on LT after CCD commissioned)
FRoDOSpec:
• SRIF-funded project with Southampton
(complete late 2005)
• Fibre-fed RObotic Dual-beam Optical
Spectrograph
• Resolution R = 4000 and 8000
• Wavelength coverage 3750 – 9000Å
• 100 fibre integral field giving 10x10”
coverage
Robotic Control System
Steve Fraser, Iain Steele (JMU)
• Optimal Dispatch Scheduler
• Sequencing System
– Control telescope and instrumentation
• In operation since April 2004
LT Operating Modes
• Real-Time Interactive (RTI) / Planetarium.
– For schools, planetarium, demonstrations.
• Target of Opportunity.
– Control requests pushed by software agents.
– Rapid response to external triggers (GCN).
• Scheduled.
– Active, pulls observations from scheduler/queue.
Weighting functions
• Height - To ensure observations are performed at low airmass.
• Transit height - We aim to catch targets as they approach
meridian (HA=0) and are at their best for observing.
• Slew -Avoid excessive slewing oby favouring close targets.
• Lateness - Intended to clear observations from the database as
they approach expiry date.
• Missed Windows -Periodic monitoring programs - need to
maintain regularity of data obtained.
• Fairness - Apportions the various condition time blocks fairly
between proposals, users, TAGs over extended period.
• Scientific Priority - Choose the programs deemed to be highest
priority by TAGs and maximises scientific return.
• Conditions - Attempts to match observation requirements to
current lunar, seeing and photometricity conditions.
Scheduling policies
Score =
w
.
f
(
s
)
∑ i i i
i
Wi
= weight associated with schedule parameter i
fi()
= weighting function applied to parameter i
Si
= scheduling parameter i
A scheduling policy is a collection {[w], [f]}
Current LT performance
• Good mechanical stability
• No windshake detectable < 40 km/h
• Pointing 10 arcsec (not yet calibrated the encoder
non-linearity)
• Tracking limits exposures to < 3 minutes
Comet C/2002 T7 LINEAR
(Fitzsimmons, QUB)
Integrated V ~ 7·5
100-sec exposure
Distance from Earth = 1·81 AU
Distance from Sun = 1·4 AU
Dust coma radius ~32 arcsec
≡4·3x104 km
Dust tail Length > 3·8 arcmin
≡3·0x105 km
Note non-sidereal tracking
Closest asteroid ever observed
• Asteroid 2004FH
• Passed 43000 km from Earth
on Thursday 18/3/04
• Observations used to refine
orbit calculations.
Dwarf Nova monitoring with the LT
(Steeghs, CfA, Harvard)
The first two epochs of U
Geminorum
30s i’-exposure
inner accretion disc/accretor
u’
B
...
outer disc . . .
V
r’
donor star/ cool disc
i’
Supernova Lightcurves (Meikle et al., IC)
• Discovered 12/01/04
• In starburst galaxy NGC 3683
• Reported 15/01/04 (IAUC 8269)
• Observed with LT 16/01/04
(IAUC 8270)
• Type Ic, ~3 weeks post-max
• Colours give Av>1 (in host)
• Important link to GRB?
• Monitoring continues with LT
LT Observations of Seyfert Galaxies
(Mkn79 – McHardy, Southampton)
•
Test prediction that X-ray/optical correlation is stronger in AGN with large
black holes.
•
Determine whether X-ray/optical lag varies with optical wavelength, as
expected in X-ray reprocessing models for the optical emission.
i’ = 13·381 +/- 0·003 (30 sec)
u’= 14·086 +/- 0·013 (60 sec)
Novae in External Galaxies – M81
LT (Jan 2004) + INT WFC
INT WFC
April 2003
(M. Darnley, E.J. Kerins, A. Newsam & M. Bode, JMU)
Current Status and Near Future
• 70 per cent robotic science operations
• 30 per cent commissioning
• IR camera and prototype spectrograph
commissioning in September
• We aim to leave site in October…
http://telescope.livjm.ac.uk/
User Community (i.e., You)
• UK Astronomical Community (40% - PATT; 30
projects approved for first semester)
• Liverpool JMU (30% ; 15 approved projects)
• Spanish Astronomical Community (20% - CAT; 10
approved projects)
• International Time (5% - CCI)
• Schools plus Amateurs (5% - NSO + BAA)
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Two phase submission process
Observing Tool to submit project details
Fair & Efficient scheduling algorithm
Data reduction pipeline and Monitoring tools
http://telescope.livjm.ac.uk/
Lots of pretty pictures…