Iain Steele
Liverpool John Moores University, UK.

Outline• Liverpool Telescope• “User view” of the robotic telescope• Science Examples• Key elements for robotic operations• Discussion and questions

• First light in July 2003,
robotic observations beganin 2004.
• Clamshell design enclosure;
two shutters, three separate
portals (3 mins to open).
• Designed for rapid follow-upof transient sources such asnovae, supernovae andGRBs.
• World’s largest fullyautonomous, robotic
telescope. Not ‘remotecontrol’.

ORM, La Palma (342ºE, 29ºN)ll

Excellent conditions & simple
logistics (4 hour flight!)
Northern Equatorial site still
provides excellent access to alarge fraction of the LSST fieldδ = 0ºδ = -10º
Altitudeδ = -20ºδ = -30ºAM• Ritchey-Chrétien Cassegrain optics (f/3
primary mirror)• Primary mirror (M1): 2.0m diameter(0.45m central bore)• Secondary mirror (M2): 0.62m diameter(moves axially for focus)• Altitude/azimuth mount. Altitude range:
25°–88°• Slew rate 2°/sec on all axes
• Acquisition and Guidance (A&G) box atCassegrain focus gives one straightthrough port and eight science fold ports
accessed by deployable science foldmirror at 45°. Instrument Change Time <30 seconds.
J. Marchant, LT.

International Common User Facility
Currently Each Semester:•• 300 hours for LJMU staff (JMU)•• 300 hours for other UK users (PATT)•• 150 hours for Spanish users (CAT)C. Copperwheat

50 hours international (CCI) time
Up to 50 hours OPTICON time (EU)
150 hours (UK + Spain) for education via the N

Observing Procedure
Phase 1
• Users submit a proposal via the relevant call. Two deadlines each year for 8 month long semesters (onemonth overlap at the start and end of every semester).
• Peer review process.
Phase 2• Users enter co-ordinatesand observational
constraints into online
Java tool or via remotetelescope mark-up
language (RTML) for someinstruments.
• Wizards available for each
instrument• Intelligent schedulingsystem identifies priority
observation.
• GRB triggers from SWIFTimmediate override ofcurrent observation andcarry out RINGO3
polarimetric monitoring.

Currently Integrating with TOM Toolkit

Timing constraints
Five types of timing constraint which control when and how often targets are observed:
FLEXIBLE time : observations can be carried out at any time during the semester when theobserving conditions are appropriate.
MONITOR time : observations are required regularly according to user-specified cadence.
INTERVAL time : observations are taken as often as possible according to the specifiedinterval.
PHASED time : observations at a particular phase of periodic cycle e.g. eclipsing binary.
FIXED time : observations will only be carried out at a specified time, or not at all e.g.
occultations, or observations which must be simultaneous with a scheduled observation onsome other facility (very intrusive to telescope operation so must be a clear need).

Robotic control system
Dispatch Scheduler selects next observation according to algorithm combining:
1. Proposal science priority (A, B or C).
2. Repeat observations have a higher priority than one-off observations.
3. Urgent observations have a higher priority.
4. Ratio of current elevation versus highest possible elevation that night.
5. Matching of actual (seeing/lunar) conditions to those requested.
Calibrations:Standards observed every ~3 hours, and whenno science groups available
Twilight flats: obtained mostmornings/evenings.
Scheduler overrides:
Two types:
1. Pre-planned 'fixed' groups(e.g. exoplanet transit)
2. Immediate, target-of-opportunity(e.g. gamma-ray burst)
http://telescope.livjm.ac.uk/TelInst/Robotic/

Benefits of robotic observing
Operational• Low operational costs: main cost is staffing. No visiting astronomers staying on La Palma.
• Site visits every ~4-6 months, 2-3 staff for 1 week.
• Safer- unmanned, no visiting astronomers, no-one on site or in Liverpool overnight.
• Engineers break things! Reliability is always better when no-one is on site.
• Continued operation through COVID-19 pandemic when all other telescopes on La Palmaclosed down.
Science• Rapid response to triggers: GRB science. On target and taking data within ~2 mins of trigger.
• Observing efficiency, little down time- all instruments on telescope all the time
• Standardized observing procedures make data pipelining easier• Efficient interleaving of science programs, typically 15-20 different programs per night• Regular and intensive monitoring easily available depending on science requirements

http://telescope.livjm.ac.uk/TelInst/Robotic/

Instrumentation● IO:O – 10x10 arcmin optical imager (many filters)● IO:I – 6x6 arcmin near-IR imager (H-band)● FRODOspec – fibre-fed integral field spectrometer
R~2500/5500, red+blue simultaneously● SPRAT – long-slit spectrometerR~ 350, 400-800 nm wavelength coverage● LOTUS – long-slit UV spectrometer
R~300, 320 – 630 nm wavelength coverage● RISE – 9 arcmin diam. rapid-readout (0.8 sec) optical imager
Large (1.0” binned) pixels but PSF still fully sampled
Fixed (V+R) filter● MOPTOP– multicolour polarimeter● Sky-cameras – three wide-field imagers (all-sky, 9º, 1º)
Photometry down to 6th, 13th, 18th mag

Data Pipelines for all instruments

Data to users in < 10 minutes

Science: Transient follow-uplDiverse instrument suite and robotic control makes the LT apowerful tool for the follow-up of transient sources

SN 2011fe:
Nugent et al. (Nature, 2011)

Science: Rapid Supernova follow-up
SN2019gep discovered by Zwicky Transient Facility
lBroad lined type Ic SNl Earliest ever spectrum of a stripped-envelope supernova from LT
llMonitoring campaign reveals shock breakout in a massive shell ofdense circumstellar material

Ho et al. (2019)

Science: Recurrent Nova super-remnant

M31N 2008-12a most
rapidly-recurrent Nova
(every year)
l Massive ‘bubble’ causedby pile-up of surrounding
ISM materiall Likely SN Ia progenitor:
powerful source for thestudy of supernova
originsl

Darnley et al. (2019, Nature)

Science: Multimessenger follow-up

First spectrum following up
IceCube-170922A neutrinoevent (IceCube Collaboration2018)
SPRAT spectra of candidate
counterparts obtained during
GW151226 campaign(Copperwheat et al. 2016)

Science: Polarimetric follow-up of Swift GRBs

Mundell et al. (2013, Nature)

Science: LT observations of TRAPPIST-1• 3 Earth-sized planets found transiting a 0.08Msun star
12 parsecs away
• 7 planets orbit star within distance of Mercury orbit.
• Transit observations taken using the IO:O imager
camera on the Liverpool Telescope (50 hours).
• Monitoring how light from the star changes when theplanet passes in front of it.

Gillon et al. 2017, Nature, 542, 456.

KEY ELEMENTS FOR ROBOTIC
OPERATION• AUTOMATIC FAULT RECOVERY– Devolved Responsibilities to subsystem– Robust state model• ”ROBOTIC CONTROL SYSTEM” – VIRTUAL ASTRONOMER– Database for Scheduling Observations (“What next?”)– Sequencing Commands (“What commands in what order”)– Reactive (“What to do when something unpredictable happens?)• RELIABLE ENVIRONMENTAL MONITORING– Safety Interlock Systems– Weather– Sky Conditions• STANDARDIZED SOFTWARE APIs FOR ALL INSTRUMENTS• DATA PIPELINES THAT CAN ASSESS DATA QUALITY IN REAL TIME
• (ROBUST HARDWARE)

FAULT RECOVERY / RETURN TO AKNOWN STATE• AFTER ANY FAULTREINITALIZE ALL
MECHANISMS!

STANDBY

FAULTRECOVERYINITIALIZEOPERATIONALROBOTIC CONTROL SYSTEM• Fraser & Steele (2002), Proc SPIE 4848

SCHEDULING• Simple Dispatch Scheduler works well given changeableconditions limit “look ahead” time horizon• Develop metrics for variables such as– Science Priority– Airmass– Time to set– Time left in semester– Matching seeing and sky brightness• Combine multiplicatively and pick what is best to do now.
• Whatever solution you choose users will say you are doing
it wrong!
• Fraser (2008), Proc SPIE, 7019

DATABASE

Steele (1997), Proc SPIE, 3112, 222
Steele (1998), Proc SPIE, 351, 232
Fraser (2002), Proc SPIE, 4848, 443
Fraser (2004), Proc SPIE, 5493, 331
Smith (2010), Proc SPIE, 7737, 11

ENVIRONMENTAL MONITORING••BASIC THINGS LIKE HUMIDITY,TEMPERATURE, RAIN CAN BE
MEASURED WITH A WEATHER MAST
CLOUD COVER– 10 MICRON SKY TEMPERATURES(Marchant (2008), Proc SPIE, 7012, 3)– SATELLITE DATA (Smith et al, (2018) Proc
SPIE, 10704– PHOTOMETRIC ZERO POINTSSTANDARDIZED INSTRUMENT API

Mottram (2004)
Proc SPIE 5492

User Support: a warning!
• We operated for first few years in a more conventional“service observing” mode.
• When we moved to full robotic operations, user
support requirements did NOT decrease– Questions about optimal use– Questions about why an observation did/did not work– Questions about data products• An expectation that since the telescope is robotic
everything is done for you!
• A lack of sense of user ownership of data can mean
publication delays. Ongoing engagement post datataking needed to combat this.

But it is worth it!

High Impact papers…

High Impact papers…

A
A new 4.0m Robotic Telescope• In design stage. First light 2024.
• 4 metre segmented primary mirror, fullyautonomous and robotic. Similar in designto LT.
• Focused on time domain science andfollow-up.
• Agile and fast slewing. Lightweight andcompact.
• Euro 25 million project with collaboratorsfrom Spain, Thailand, (China?). Looking for
new partners.
• Selected as STFC Priority Project• At least 5 focal stations for
instrumentation: cassegrain or nasmyth.
Copperwheat, C. M. et al., 2014, SPIE, 9145, 11

http://www.robotictelescope.org/

Motivation: transient science
Serious issue in the LSST era:lllllvast increase in discovery rate(~1e6 alerts per night!)
Significant risk that the transientscience potential of the survey will
not be fully realised

Initial classifications from LSST
photometry and machine learningalgorithms
Spectroscopy required for identification ofrare subtypes and new phenomena, andexploitation of the most interesting targets
NRT design requirements: Opt/IR
spectroscopy. Low/intermediate resolution.
Automatic response to triggers within 30
seconds. Small observing overheads.
Depths down to R~21-22‘Faint andfast’(Adapted from LSST science book)33

LT: telescope.livjm.ac.uk
NRT: www.robotictelescope.org

Motivation: gravitational waveslllll

A whole new type of astronomy:transient detections via nonelectromagnetic means. Hugediscovery potential
Electromagnetic follow-up programme
active. EM counterpart detection
achieved.

Full LIGO/Virgo sensitivity in ~2022: expected discovery rate 100stransients per year
Observational challenges: ~few deg positional uncertainty, fast fading (?)
Requirements: wide FoV search capability. Rapid response. Efficient
spectroscopic classification of large numbers of candidates. Infrared.
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