Ulrich Mall

CARMENES: Calar Alto high-resolution search for M dwarfs with exo-earths with a near-infrared Echelle spectrograph

CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a next-generation instrument to be built for the 3.5m telescope at the Calar Alto Observatory by a consortium of Spanish and German institutions. Conducting a five-year exoplanet survey targeting ~ 300 M stars with the completed instrument is an integral part of the project. The CARMENES instrument consists of two separate spectrographs covering the wavelength range from 0.52 to 1.7 μm at a spectral resolution of R = 85, 000, fed by fibers from the Cassegrain focus of the telescope. The spectrographs are housed in a temperature-stabilized environment in vacuum tanks, to enable a 1m/s radial velocity precision employing a simultaneous ThAr calibration.

LUCIFER1: performance results

LUCIFER1 is a NIR camera and spectrograph installed at the Large Binocular Telescope (LBT). Working in the wavelength range of 0.9-2.5micron, the instrument is designed for direct imaging and spectroscopy with 3 different cameras. A set of longslit masks as well as up to 23 user defined (MOS) masks are available. The set of user defined masks can be exchanged while the instrument is at operating temperature. Extensive tests have been done on the electro-mechanical functions, image motion due to flexure, optical quality, instrument software, calibration and especially on the multi-object spectroscopy. Also a detailed characterization of the instruments properties in the different observing modes has been carried out. Results are presented and compared to the specifications.

LUCIFER status report: summer 2008

LUCIFER is a NIR spectrograph and imager (wavelength range 0.9 to 2.5 micron) for the Large Binocular Telescope (LBT) on Mt. Graham, Arizona, working at cryogenic temperatures of less than 70K. Two instruments are built by a consortium of five German institutes and will be mounted at the bent Gregorian foci of the two individual telescope mirrors. Three exchangable cameras are available for imaging and spectroscopy: two of them are optimized for seeing-limited conditions, a third camera for the diffraction limited case will be used with the LBT adaptive secondary mirror working. Up to 33 exchangeable masks are available for longslit or multi-object spectroscopy (MOS) over the full field of view (FOV). Both MOS-units (LUCIFER 1 and LUCIFER 2) and the auxiliary cryostats together with the control electronics have been completed. The observational software-package is in its final stage of preparation. After the total integration of LUCIFER 1 extensive tests were done for all electro-mechanical functions and the verification of the instrument started. The results of the tests are presented in detail and are compared with the specifications.

Characterization, testing, and operation of Omega2000 wide-field infrared camera

Omega2000 is the first near infrared (NIR) wide field camera installed on the 3.5 m telescope at Calar Alto which operates with a 2kx2k HAWAII-2 FPA. Each component of the camera system must suit high requirements to exploit the facilities provided by the imaging sensor. To meet these requirements was a great challenge in design and realization of the optics, the mechanical part and the electronics. The cryogenic optical system with a warm mirror baffle can produce excellent optical quality and high sensitivity over the whole 15.4x15.4 arcmin field of view. The readout electronics together with the camera control software provide multi functional data acquisition and the camera control software can perform the readout and on-line data reduction simultaneously at a high data rate. Different operational and readout modes of the data acquisition of the detector both for engineering and scientific purpose were implemented, tested and optimized and the characteristics of three HAWAII-2 detectors were also determined in their hardware and software environment. Initial astronomical observations were carried out successfully in autumn 2003.

The MPIA detector system for the LBT instruments LUCIFER and LINC-NIRVANA

We describe the detector subsystem developed at MPIA to operate the Rockwell Hawaii-2 detectors used in the LUCIFER and LINC-NIRVANA instruments for the Large Binocular Telescope (LBT). To fully exploit the capabilities of the LBT, the detector subsystem must meet, especially in the case of the low background applications foreseen for LUCIFER, very stringent requirements in terms of stability and read noise. A read-out electronics has been developed at MPIA, which is able to read the 32 outputs of the Hawaii-2 detector, as well as the 4 reference signals available in this chip. The noise figure associated to the electronics alone is negligible with respect to the intrinsic read noise of the detector, while the cloking patterns and the value of the bias voltages applied to the chip are optimized in order to maximize the signal to noise ratio in the different operating modes. We present the results of the tests performed with the LUCIFER science detector; in particular, we describe the main properties of the detector: read noise, dark current, linearity, and long term stability, and what are the read-out schemes foreseen for different observational modes. We discuss also how the reference outputs can be used in order to correct for thermal drifts, and how effective those outputs are in removing higher frequency noise components.

Characterization and performance of the 4k x 4k Hawaii-2RG Mosaic for PANIC

PANIC, the PAnoramic Near-Infrared Camera for Calar Alto, is one of the next generation instruments for this observatory. In order to cover a field of view of approximately 30 arcmin, PANIC uses a mosaic of four 2k x 2k HAWAII-2RG arrays from Teledyne. This document presents the preliminary results of the basic characterization of the mosaic. The performance of the system as a whole, as well as the in-house readout electronics and software capabilities will also be briefly discussed.

LINC-NIRVANA for the large binocular telescope: setting up the world’s largest near infrared binoculars for astronomy

LINC-NIRVANA (LN) is the near-infrared, Fizeau-type imaging interferometer for the large binocular telescope (LBT) on Mt. Graham, Arizona (elevation of 3267 m). The instrument is currently being built by a consortium of German and Italian institutes under the leadership of the Max Planck Institute for Astronomy in Heidelberg, Germany. It will combine the radiation from both 8.4 m primary mirrors of LBT in such a way that the sensitivity of a 11.9 m telescope and the spatial resolution of a 22.8 m telescope will be obtained within a 10.5×10.5 arcsec 2 scientific field of view. Interferometric fringes of the combined beams are tracked in an oval field with diameters of 1 and 1.5 arcmin. In addition, both incoming beams are individually corrected by LN’s multiconjugate adaptive optics system to reduce atmospheric image distortion over a circular field of up to 6 arcmin in diameter. A comprehensive technical overview of the instrument is presented, comprising the detailed design of LN’s four major systems for interferometric imaging and fringe tracking, both in the near infrared range of 1 to 2.4 μm, as well as atmospheric turbulence correction at two altitudes, both in the visible range of 0.6 to 0.9 μm. The resulting performance capabilities and a short outlook of some of the major science goals will be presented. In addition, the roadmap for the related assembly, integration, and verification process are discussed. To avoid late interface-related risks, strategies for early hardware as well as software interactions with the telescope have been elaborated. The goal is to ship LN to the LBT in 2014.

Laboratory performance tests of PANIC, the panoramic NIR imager for Calar Alto

PANIC is developed at MPIA, Heidelberg, Germany and IAA, Granada, Spain. This instrument will cover a field of view of 0.5x0.5 degrees at the 2.2m telescope in the spectral bands Z to K. All hardware has been manufactured, the instrument is currently assembled and tested. In this contribution we describe results of some tests.

PANIC: the new panoramic NIR camera for Calar Alto

PANIC is a wide-field NIR camera, which is currently under development for the Calar Alto observatory (CAHA) in Spain. It uses a mosaic of four Hawaii-2RG detectors and covers the spectral range from 0.8-2.5 μm (z to K-band). The field-of-view is 30×30 arcmin. This instrument can be used at the 2.2m telescope (0.45arcsec/pixel, 0.5×0.5 degree FOV) and at the 3.5m telescope (0.23arcsec/pixel, 0.25×0.25 degree FOV). The operating temperature is about 77K, achieved by liquid Nitrogen cooling. The cryogenic optics has three flat folding mirrors with diameters up to 282 mm and nine lenses with diameters between 130 mm and 255 mm. A compact filter unit can carry up to 19 filters distributed over four filter wheels. Narrow band (1%) filters can be used. The instrument has a diameter of 1.1 m and it is about 1 m long. The weight limit of 400 kg at the 2.2m telescope requires a light-weight cryostat design. The aluminium vacuum vessel and radiation shield have wall thicknesses of only 6 mm and 3 mm respectively.

LINC-NIRVANA, integration of an interferometric and cryogenic camera: first verification results

LINC-NIRVANA is an interferometric imaging camera, which combines the two 8.4 m telescopes of the Large Binocular Telescope (LBT). The instrument operates in the wavelength range from 1.1 μm to 2.4 μm, covering the J, H and K-bands. The beam combining camera (NIRCS) offers the possibility to achieve diffraction limited images with the spatial resolution of a 23 m telescope. This camera, which combines the AO corrected beams of both telescopes, is designed to deliver a 10 arcsec x 10 arcsec diffraction limited field of view. The optics and cryo-mechanics are designed for operation at 60 Kelvin. Equipped with a HAWAII-2 detector mounted on a rotation stage in order to compensate for the sky rotation, a filter wheel and a dichroic wheel to split the light into the science channel and the fringe tracking channel, the camera is fairly large and complex and requires certain features to be considered and tested. The verification of all these components follows a challenging AIV plan. We describe this AIV phase from initial integration of individual units to the final verification tests of the complete system. We report the performance of the cryogenic opto-mechanics and of the science detector. We also demonstrate the functionality of the cryo-mechanics and the cryo-cooling at sub-system level, which represents the current state of integration. Finally, we discuss key elements of our design and potential pros and cons.