In Flange Derotator Design for the 4m DAG telescope

The field rotation effect can be described as observing the gyration of an object with the pupil of the Eastern Anatolian Observatory (DAG) telescope around the optical axis under the influence of the latitude of the observatory while the telescope is following that astronomical object. This is possible as a result of the alt-azimuthal mount of the telescope. (the orientation of the astronomical observed object, the parallactic angle, is defined as "q") Since the CCD has a low signal on noise ratio, it necessitates long integration time that can vary from a few minutes to hours. It is essential to correct and compensate the rotation of the optical field caused by the earth's rotation during the monitoring of the astronomical object. A (field) derotator is a class of devices that is used to correct the optical field rotation. In a telescope of a Ritchey-Chretien, Nasmyth configuration, the device must be integrated between the scientific instruments and the M3 mirror. The anastigmatic and the anachromatic features of this type of derotator is the main reason that it is chosen. These characteristics are provided by the K-Mirror design. The aim of this study is to evaluate the possibility to integrate the derotator in the central hole of the telescope fork and to evaluate the mechanical/optical features of the model.Authors would like to thank Isik University, ATASAM, Ataturk University, and the Ministry of Development for the funding and supportPublisher's Versio

ANDES, the high resolution spectrograph for the ELT:Calibration Unit(s)

The instrumentation plan for the ELT foresees the ArmazoNes high Dispersion Echelle Spectrograph (ANDES). The ANDES-project and consortium entered phase B in January 2022 and underwent several (internal and external) revisions by now to ensure that the requirements and eventually the challenging goals can be met by the physical design of the spectrograph. Among its main scientific goals are the detection of atmospheres of exoplanets and the determination of fundamental physical constants. For this, high radial velocity precision and accuracy are required. Even though the ANDES-spectrograph is designed for maximum intrinsic stability, a calibration and thus a calibration unit is mandatory. To allow for maximum flexibility and modularity the calibration unit is physically split into three calibration units. We show the design of the calibration units and their individual components, where possible. This includes the electronics, the mechanics, the software supporting and controlling the light guiding and calibration sources.</p

ANDES, the high resolution spectrograph for the ELT: science case, baseline design and path to construction

International audienc