We have designed, built and are deploying complete 1-meter autonomous telescopes, operating as a global network with centralized scheduling. The 1-meter prototype in Santa Barbara was used as a test facility to validate all optical, mechanical, electrical and software functions prior to wider deployment.
The first 1-meter deployment was to ELP, MacDonald Observatory, in April 2012. Three 1-meter telescopes were deployed to Cerro Tololo, Chile in September 2012. Three more were installed at SAAO, Sutherland, South Africa in February 2013. Two more were installed at Siding Spring Observatory, Australia in May 2013.
As of May 2013 ten 1m telescopes have been deployed (counting our engineering installation at our headquarters), with parts for 5 more 1-m telescopes on hand (2 of which will go to Ali Observatory in China). They join our two 2-m telescopes and the 0.8m BOS telescope and are being operated as part of our global network. See /camera for live views of our working sites. See this recent paper about the Las Cumbres Observatory global telescope network and future plans.
This video shows a schematic of an LCO 1-meter telescope responding rapidly to a request for observations. The telescope slews to the target and then tracks it. Simultaneously the dome rotates into alignment, both dome shutters open, and the mirror cover opens (you can see reflections in the mirror) so the telescope is ready to start imaging in the requested filters. Normally each telescope will already be open and observing, but this shows all the steps necessary to fulfill an observing request. The 1-meter telescopes can move from anywhere to tracking and observing any new target in 30 seconds or less.
The main elements of the 1m mount are:
- Modular construction for simplified assembly, alignment and deployment. Each telescope is deployed as a few pre-aligned components, and is typically operating about 1-week after arrival at the prepared site.
- Large steel pieces were designed at LCO and built by Rettig Machine, Redlands CA. These include:
- Triangular Base, tilted for latitude, on steel pedestals bolted to a concrete pier inside each dome. The primary mirror is about 2m above ground level
- RA "sandwich", containing the drive-side and following steel rollers for the C-Ring, drive dust cover and encoders
- 2m diameter C-ring on one direct-driven RA roller and one following roller; the C-ring is lifted & locked above its rollers for shipping.
- Dome and telescope can Slew to and track on any source within 30-sec.
- 15° horizon limit (AirMass=3.8), including HA limits of -4.6h to +4.6h
- Direct Dec drive to a sector wheel, with an additional encoder disk. Drive motors, encoders and servo control system are the same for 1-meter, 0.4-meter and 0.8-meter (BOS) telescopes.
- RA and DEC Energy Chains for cooling lines, data and science fiber feeds.
The main elements of the Optical Tube Assembly (OTA) are:
- Steel Mirror Cell containing 18-point whiffle tree and central hub primary support system
- the Mirror Cell forms the main load bearing structure for the OTA.
- Telescopes are shipped with complete mounts, drives and mirror cells, then optics and instruments added.
- Lightweight Hextek (Tucson, Arizona) Borosilicate mirrors polished and coated (Al overcoated with Quartz) by LZOS in Russia
- Roll-type mirror cover and Hartmann screen just above the primary
- Primary stray-light baffle assembly
- Carbon Fiber truss assembly supporting an invar secondary spider support
- 3-axis M2 assembly for focus and remote tilt collimation
- Secondary stray light baffle assembly
- Support for the main science instrument in a straight-through cassegrain port, 0.8deg field of view with doublet corrector.
- The final science imager will use a Fairchild 4K CCD with fast readout and flexible observing modes; 27-arcmin field of view with 0.4" pixels
- Support for 4 off-axis fixed ports for autoguiding, fast-photometry and fiber feed for a bench-mounted high resolution spectrograph (NRES) at each site.
- LCO has developed a comprehensive embedded control system based on the Blackfin processor family, to enable
- networked control of motors, fans and all mechanisms such as focus, collimation, filter wheels, covers, and all sensors such as temperature and position probes.
- The Blackfin architecture also enables us to design "smart" power modules to support power cycling and current monitoring of each sub-system.
- Support for up to four instrument electronics crates below each mirror cell, for control of all instrumentation, fans, sensors and monitoring equipment
Each 1-meter telescope was deployed initially (2012/2013) with
- an SBIG STX-16803, with 4Kx4K pixels, each 0.23arcsec, for a Field of View (FoV) of 16x16 arcmin.
These were replaced by the main science imager:
- Sinistro CCD, Fairchild CCD-486 BI, 4Kx4K, 0.39arcsec pixels, FoV 27x27arcmin
- Similar to the Spectral cameras on our 2m FTN and FTS, but with improved (in-house) electronics for faster and quieter readout. Cryotiger cooling.
Both these CCDs attach below a Filter/Shutter unit with carbon fiber disk shutter and 3 wheels, each 8 positions, providing
- Johnson/Cousins UBVRI
- Sloan primed ugri, PanStarrs (short) zs,ys
- narrow band filters
Anexposure time calculator can be used to estimate typical exposure times for our different aperture classes.
There are 4 off-axis ports which can all see light simultaneously with the main science camera, see the 1m focal plane diagram.
One port to the North of the main science field always has an FLI autoguider with 0.34" pixels and 5.7' Field of View. We intend to deploy on least one telescope per site a Lucky Imaging/High Speed Photometer (LIHSP) consisting of:
- An Andor iXon-3 888 EM-CCD, 1024x1024, 0.34arcsec pixels, FoV 5.7arcmin
- Single 10-position Filter Wheel with selection of Johnson/Cousins/Landolt & Sloan filters
Future 1m Instrumentation
Two telescopes per site will have off-axis ports to provide a fiber feed for the Network Robotic Echelle Spectrograph (NRES). Each spectrograph will accept fibers from two one meters simultaneously, and provide autonomous target acquisition, placement and guiding on the fiber while spectra are obtained. This capability has already been tested with the FLOYDS spectrographs on our 2m telescopes. We are currently installing a prototype on our 0.8-meter BOS telescope and will build 6 copies, one for each site.
The main elements of the Facility Control System (common to all telescope classes) are
- a Java-based Telescope Control System (jTCS) utilizing the Java Agent DEvelopment (JADE) framework, providing:
- an Astrometric agent and guiding based on the TPK kernel, using Astrometry.Net for automatic RT WCS fitting & Tpoint modeling
- axes control agents to servo on the latest target coordinates
- agents to control all enclosure and telescope systems, including focus - automatically adjusted as a function of temperature and Zenith Angle
- agents monitoring IERS bulletins, and to configure each telescope, instruments and focal plane
- agents for multiple instrument and guider selection, filter wheels, exposure and subsystem control for requested observations
- RT Transparency agent compares magnitudes of stars measured in each field (sextractor) to known values from Landolt, Stetson, Sloan, Tycho, APASS.
- Agents monitor, and will attempt to recover each susbsytem, including power-cycling if necessary, to maintain autonomous operations.
- All data are stored in a telemetry database, which can be graphed in RT at the web URL level to analyze performance.
- Proposal Observation Network Database (POND) to monitor observations from request to completion
- Flash reduced data available on-site for quick checks and quality monitoring: image quality, WCS and transparency
- BANZAI Python pipeline to remove instrument signatures and derive source information to be stored in LCO archive
- Telescope Network Scheduler to schedule (and re-schedule) observations across the network: for LCOGT the network is the telescope