Many components of our STELLA telescopes located on Tenerife, which were built by Halfmann in the 2000s have reached the end of their life with no replacement parts available. A solution was necessary to guarantee continuous operation and support for the next ten years. The prerequisite for the retrofit, however, was that the mechanical components remain largely untouched in order to simplify the upgrade. We decided to remove all the existing electronics in the main control cabinet. In order to avoid electronic interference in the scientific instruments, we took several precautions. This included an isolating transformer, line filters and power chokes for the servo drivers. All of the control electronics as well as the sensory inputs is now handled by Beckhoff components. A Beckhoff PLC CX5140 is the new ”electronic brain” replacing a Linux computer running the telescope control firmware. The new telescope control firmware written in TwinCAT3 is available as open source. MQTT messages are used to command the telescope and report sensor values and position information. Sensor measurements and the state of the telescope are logged in an Influx∗-database and visualized using Grafana†. Future enhancements include an improved guiding of the telescope using machine vision and a GigE camera in a closed loop on the PLC.
The BMK10k is a 30cm-aperture lens telescope ‘Ballistische Messkammer 75/2,5/18’, now equipped with a 100Megapixel STA1600LN CCD camera. With a plate scale of 2.54 arcsec per pixel, it delivers an astrometrically well-corrected field of view of 7.25° × 7.25°. We have roboticized it with the intention of operating it from Cerro Armazones, Chile, where it saw first light in August 2019. It is currently in commissioning. Among other applications, we plan to use it to observe the Southern PLATO Field (SPF) almost continuously for three years in preparation for the PLATO satellite, which will have much reduced spatial resolution in comparison. The telescope mount was retrofitted with modern servo motors and an industrial Beckhoff programmable logic controller (PLC), allowing reliable remote telescope control, environmental monitoring, dome control, with a separate PLC ensuring safely measures to protect the telescope in case of communication loss or power failure. Communications between the TCS and the PLC firmware are accomplished with Beckhoff TwinCAT Automation Device Specification (ADS) over TCP/IP. Real-time response is realised within the PLC, and ADS has latency times on the order of a few 100 ms, sufficient for high-level control of the telescope. Using off-the-shelf industrial components has proven to be a cost-effective and reliable method of operating a fully autonomous observatory.
GREGOR at night spectrograph (GANS) is a high-resolution thermally-stabilised vacuum-enclosed fixed-format fiber-fed Echelle spectrograph. GANS will be installed starting 2018 alongside the daytime instrumentation in the building of the 1,5m Gregor Solar Telescope at the Observatorio del Teide at Izan˜a, Tenerife. Specified resolving power is R~55k with wavelength coverage from 470 to 680 nm in single shot on 2k 2k CCD with 3”, 50μm fiber on sky, and with space between orders for simultaneous calibration light in the form of a Fabry-Perot Etalon or a Laser-comb spectrum. The end-to-end simulated radial velocity precision performance estimate is 2 ms−1. The main observing project of GANS will be the ground-based follow-up survey of TESS and PLATO2.0 exoplanet candidates. GANS will observe its targets in autonomous operation without human intervention using the normally human-operated day-time observatory. Limited operations will begin in first half of 2019 with first science-light planned for summer 2019.
STELLA is a robotic observatory on Tenerife housing two 1.2m robotic telescopes. One telescope is fibre-feeding a high-resolution (R=55,000) échelle spectrograph (SES), while the other telescope is equipped with a visible wide- field (FOV=22' x 22') imaging instrument (WiFSIP). Robotic observations started mid 2006, and the primary scientific driver is monitoring of stellar-activity related phenomena. The STELLA Control System (SCS) software package was originally tailored to the STELLA roll-off style building and high-resolution spectroscopy, but was extended over the years to support the wide-field imager, an off-axis guider for the imager, separate acquisition telescopes, classical domes, and targets-of-opportunity. The SCS allows for unattended, off-line operation of the observatory, targets can be uploaded at any time and are selected based on merit-functions in real-time (dispatch scheduling). We report on the current status of the observatory and the current capabilities of the SCS.
The STELLA project is made up of two 1.2m robotic telescopes to simultaneously monitor stellar activity
using a high-resolution spectrograph on one telescope, and an imaging instrument on the other telescope. The
STELLA Echelle spectrograph (SES) along with the building has been in operation successfully since 2006, and
is producing spectra covering the visual wavelength range between 390 and 900 nm at a resolution of 55 000. The
stability of the spectrograph over the entire two year span, measured by monitoring 15 radial velocity standard
stars, is 30 to 150 m/s rms. The Wide-field stellar imager and photometer (WIFSIP) was put into operation in
2010, when the SES-lightfeed was physically moved to the second telescope. We describe the final instrument
conguration in use now, and on the efficiency of the robotic scheduling in use at the observatory.
The All Sky Infrared Visible Analyzer (ASIVA) is an instrument principally designed to characterize sky con-
ditions for purposes of improving ground-based astronomical observational performance. The ASIVA's primary
functionality is to provide radiometrically calibrated imagery across the entire sky over the mid-infrared (IR)
spectrum (8-13 μm). Calibration procedures have been developed for purposes of quantifying the photometric
quality of the sky. These data products are used to provide the STELLA scheduler with real-time measured
conditions of the sky/clouds, including thin cirrus to better optimize observing strategy. We describe how this
can be used in the denition of the observing programs to make best use of the telescope time. Additional
research is underway to correlate infrared spectral radiance with visible-spectrum extinction.
We present the status of PEPSI, the bench-mounted fibre-fed and stabilized "Potsdam Echelle Polarimetric and
Spectroscopic Instrument" for the 2×8.4m Large Binocular Telescope in southern Arizona. PEPSI is under construction
at AIP and is scheduled for first light in 2009/10. Its ultra-high-resolution mode will deliver an unprecedented spectral
resolution of approximately R=310,000 at high efficiency throughout the entire optical/red wavelength range 390-1050nm without the need for adaptive optics. Besides its polarimetric Stokes IQUV mode, the capability to cover the
entire optical range in three exposures at resolutions of 40,000, 130,000 and 310,000 will surpass all existing facilities in
terms of light-gathering-power times spectral-coverage product. A solar feed will make use of the spectrograph also
during day time. As such, we hope that PEPSI will be the most powerful spectrometer of its kind for the years to come.
The STELLA project consists of two robotic 1.2m telescopes to simultaneously monitor stellar activity with a high resolution echelle spectrograph on one telescope, and a photometric imaging instrument on the other telescope. The STELLA observatory is located at the Observatorio del Teide on the Canary island of Tenerife. The STELLA Echelle spectrograph (SES) has been operated in robotic mode for two years now, and produced approximately 10,000 spectra of the entire optical range between 390 and 900 nm at a spectral resolution of 55,000 with a peak shutter-open time of 93%. Although we do not use an iodine cell nor an actively stabilized chamber, its average radial velocity precision over the past two years was 60 to 150m/s rms, depending on target. The Wide-Field STELLA Imaging Photometer (WIFSIP) is currently being tested and will enter operation early 2009. In this paper, we present an update report on the first two years of operation.
In the last few years the ubiquitous availability of high bandwidth networks has changed the way both robotic and non-robotic telescopes operate, with single isolated telescopes being integrated into expanding "smart" telescope networks that can span continents and respond to transient events in seconds. The Heterogeneous Telescope Networks (HTN)* Consortium represents a number of major research groups in the field of robotic telescopes, and together we are proposing a standards based approach to providing interoperability between the existing proprietary telescope networks. We further propose standards for interoperability, and integration with, the emerging Virtual Observatory.
We present the results of the first interoperability meeting held last year and discuss the protocol and transport standards agreed at the meeting, which deals with the complex issue of how to optimally schedule observations on geographically distributed resources. We discuss a free market approach to this scheduling problem, which must initially be based on ad-hoc agreements between the participants in the network, but which may eventually expand into a electronic market for the exchange of telescope time.
Fully robotic observatories open a cheap, but nevertheless compelling
window for scientific research. Though the telescopes are small and from the engineering point of view mostly simple, the challenging part lies in the software necessary for robotic action. If one carefully plans the development and tries to be as generic as possible, it is appropriate to create a basic software package that has the capabilities to be used on almost any robotic observatory. The aim of this article is to introduce the software used on the STELLA robotic telescope, operated by the Astrophysikalisches Institut Potsdam. Emphasis is put on issues addressing adaptation of the software to different robotic telescopes. The entire package is written in Sun's Java 1.3. It is expected to be released under the GNU public license later this year.
We describe the operations model for our two robotic photoelectric telescopes and give a brief status report after more than three years of routine operation in southern Arizona. The telescopes operate fully unattended, also the observatory itself is automatic. A site-control computer monitors weather sensors and operates the roof while the telescope control computers operate the photometers and accept input files from and provides nightly observations to the astronomer in Vienna. In the first three years of operation a total of 3.3 million individual scientific measurements were made.
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