A more accurate and efficient CAFE instrument
The last update of the CAFE instrument on the 2.2-m telescope will provide a higher accuracy for the studies of stars and exoplanets
The Calar Alto observatory has enhanced the accuracy of the CAFE (Calar Alto Fiber-fed Échelle spectrograph) instrument, installed since 2011 on the 2.2-m telescope. The improvement is based on a new temperature control system and the renewal of a key element of the instrument.
CAFE is a high-resolution spectrograph, an instrument that spreads the light coming from an astronomical object into many colors so as to analyze it. With CAFE, various international teams of astronomers have performed studies mainly focused on stellar physics and on exoplanets that is, planets around stars different from the Sun.
One of the updates applied to the instrument was a change of the diffraction grating, the part specifically designed to spread into colors the light coming from the telescope. “With the renewal of this key piece, we have recovered the initial efficiency of the instrument”, says Marco Azzaro, astronomer in charge of the instrument update at the observatory. “In addition, thanks to the improved climate control performed, we are getting a more stable temperature, therefore a higher precision, so CAFE is now better than it was at the beginning”.
The CAFE update takes place among the recent renewal and improvement of instruments, including the high-resolution CARMENES spectrograph, installed on the 3.5-m telescope, the ongoing refurbishment of the PANIC wide-field infrared camera and the development of the future instrumentation for the LUCA (the Local Universe from Calar Alto) project.
The room where CAFE is located already included an air chamber and thermal insulation to stabilize the temperature. Now, with European Union funds, a temperature control system with air conditioning and high-accuracy sensors was added. Thanks to this new system, the temperature can be controlled with an accuracy of a tenth of a degree in the room and down to two hundreds of a degree inside the instrument. This accuracy is “about five times better than required in the call for tenders, thus far exceeds the expectations” points out Daniel Benítez, from Ingenyo, the Almeria based company in charge of the design and building of the system.
These new and improved tools, available to astronomers worldwide, promise better measurements and new findings in the near future, that shall keep the Calar Alto Observatory at the forefront of research in Astronomy and Astrophysics.
The German-Spanish Calar Alto Observatory is located at Sierra de los Filabres, north of Almería (Andalucía, Spain). It is jointly operated by the Instituto Max Planck de Astronomía in Heidelberg, Germany, and the Instituto de Astrofísica de Andalucía (CSIC) in Granada, Spain. Calar Alto has three telescopes with apertures of 1.23m, 2.2m and 3.5m. A 1.5m aperture telescope, also located at the mountain, is operated under control of the Observatorio de Madrid.
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