2. The Liverpool Telescope Iain Steele Liverpool John Moores University

4. Basic Specification Fully opening enclosure 2.0 metre f/10 ALT/AZ 2 degree / second slew speed A&G box with deployable, folding mirror, allowing support of upto 5 instruments Instrument change time < 30 seconds Common User Facility (typically 40-50 science programmes from around 30 different institutes, allocated by TAC’s) Fully Robotic (no night time supervision apart from start of night photometricity check, weekdays there is a daytime daily visit)

5. Relationships LT is owned and operated by Liverpool JMU Manufacturing facility (TTL) was owned by Liverpool JMU, now owened by Las Cumbres Observatory Faulkes Telescopes were owned by Dill Faulkes, now owned by Las Cumbres Observatory Three telescopes still part of Robonet-1.0, and Liverpool JMU has an allocation of observing time on the Faulkes Telescopes until 2010 at least.

6. Open Air enclosure gives problems with scattered moonlight

7. Operating Modes “Science Control Agent” - phase 2 database driven Background mode (does standards!) –Nothing to schedule –Seeing > 3 arcseconds (or unknown) –Something is broken (e.g. out of focus!) Target of Opportunity Mode –Immediate abort of current observing –Driven by scripts

8. Phase 2 database Specifies the observation (“what not how”) Current Methods of data entry: –Phase 2 forms via email –Menus for a specific science programme –RTML via unix socket Future Methods of data entry: –User Tool (web based - Java Web Start) –RTML via Web Services

9. Observation Types Flexible –Any time after a start date the conditions are met. Once only. Monitor –Repeat at an interval with accuracy defined by a window fraction Ephemeris –Once only, at a specified phase Fixed –At a specific time (with some error attached)

10. Scheduling from phase 2 Lateness Height Priority Missed Period Darkness matching Seeing matching Slew Transit Allocation Fraction

11. Targets of Opportunity a client script (csh) running at the telescope (e.g. GRB followup) An intelligent agent submitting Robotic Telescope Markup Language with the appropriate priority flag (e.g. exoplanet microlensing) Make it as simple or as complex as you like…

12. RTML Example http://www.estar.org.uk/documents/rtml2.1.dtd Chris Mottram TMC/estar agent_test 1 test 01 02 03.00 +45 56 01.00 J2000 V ratcam 1000.0 0.0

13. Instrumentation (mixture of general purpose and science specific) Current –RATCam - optical CCD camera –SupIRCam - JH near-IR camera –RINGO - optical polarimeter Near Future –Meaburn Spectrograph –FRODOSpec –Fast Readout CCD? Later –Wide field CCD? –SupIRCam2? (wider field, K band, grism spectra)

14. Common Features Between Instruments Completely independant Same command set ( e.g. CONFIG, DAY_CALIBRATE, NIGHT_CALIBRATE, TWILIGHT_CALIBRATE, WAVELENGTH_CALIBRATE, EXPOSE ) Knowledge of calibration procedures built into the instrument control system Electrical power kept running 24/7 No precision servo mechanisms (obtain precision via mechanical means) Daily reboot of control computers Problems with cooling…

15. RATCam Specification 2048 x 2048 pixels 0.135 arcsec/pixel Read noise < 8 electrons Binning 1x1, 2x2, 3x3, 4x4 No windowed modes Bad pixel mask available Heavy saturation results in charge persistance and observations causing this will not be allowed

16. RATCam Filter Set “Sloan” u’ g’ r’ i’ z’ Bessell B V H  Transformations to standard Sloan and Cousins systems are available on web page.

17. RATCam Calibrations Flat fields are obtained automatically in morning twilight. On average around 5 exposures through 5 filters are obtained, meaning that we get though the complete set (binned 1x1 and 2x2) about every 3-4 days. Landolt photometric standard fields are observed (twice per filter) at a range of airmasses every 2 hours.

18. RATCam Data Pipeline End of night pipeline –Debiases based on overscan region –Trims overscan –Flat fields based on latest flats Data provided to allow user to –Defringe –Apply a bad pixel mask

19. SupIRCam Now back on telescope and much improved following engineering work

20. SupIRCam specification 256 x 256 pixels HgCdTe 0.4 arcsec/pixel (1.7 arcmin FOV) Read noise = 26 electrons Dark current = 50 electrons/second JH only Linearity ~ 2% pixel-pixel sensitivity variations 2% (J), 4.5% (H) Possible J band red-leak gives higher sky background in J than H

21. SupIRCam observing Exposure times =1,2,5,10,20 and 50s Dither patterns with 1,2,5 and 9 pointings with 7 arcsec offsets. Offset time = 10 seconds (was 20 seconds) Option to do a separate sky field altogether An equal length dark frame is always taken before and after the dither. Photometric standards (UKIRT FS list) every three hours

22. SupIRCam data reduction Currently no pipeline Chris Gerardy (IC) has a prototype pipeline that can handle the bias slopes in old SupIRCam data For new data, standard Starlink or IRAF routines should be sufficient –Dark subtraction using mean of before and after darks –Create flat field from median filtering dithered science frames and divide in

23. RINGO Optical polarimeter

24. RINGO in action (GRB060418; P<8%)

25. RINGO Specification “V+R” filter (4600 - 7200 Angstroms) Same CCD as RATCam but only cooled to - 10 degC (dark current ~ 1 electon/sec) Note ability to measure optical polarization variations on short (seconds - minutes) timescales is unique Saturation limit V~5 (V~3 with lots of very short exposures)

26. RINGO Sensitivity

27. Meaburn Spectrograph On telescope, optics fixed. Needs commissioning and automated acquisition routines implementing Four, fixed wavelength ranges 4 Angstrom resolution 49 x 1.7 arcsec fibres 512 x 512 pixel array, -15 degC

28. Example Meaburn Spectrum

29. FRODOSpec Blue Arm 3800 - 5750Å, R = 2300, 6300 Red Arm 5750 - 9000Å, R = 1780, 5530 Fixed central wavelengths 11 x 11 lenslet array (0.9 arcsec “pixels”) Argon and Xenon lamps 4k x 2k detectors cooled to -100 degC Under construction in Liverpool, ships to La Palma in Summer 2007.

30. Lab Test Spectra

31. Summary LT is now generally working well. There is a good variety of instrumentation and this is important for a faciliy (rather than experiment) based obervatory. You need to keep developing new instrumentation to keep competitive Devolve as much of the detail of the instrument to its own systems (standard command set, calibration details) Avoid common systems (but use common designs!) Avoid moving parts where possible –If you can’t, avoid the need for precison –If you need precision, use mechanical rather than software/electronic technqiues Klaus’ list of pre-requisites was a good one!