arXiv subjects

Arto Järvinen

Publications and source records attributed to Arto Järvinen.

3 recordsLinked to original sources

arXiv2024

ANDES, the high-resolution spectrograph for the ELT: RIZ Spectrograph preliminary design

We present here the preliminary design of the RIZ module, one of the visible spectrographs of the ANDES instrument 1. It is a fiber-fed high-resolution, high-stability spectrograph. Its design follows the guidelines of successful predecessors such as HARPS and ESPRESSO. In this paper we present the status of the spectrograph at the preliminary design stage. The spectrograph will be a warm, vacuum-operated, thermally controlled and fiber-fed echelle spectrograph. Following the phase A design, the huge etendue of the telescope will be reformed in the instrument with a long slit made of smaller fibers. We discuss the system design of the spectrographs system.

astro-ph.IM↗

arXiv2020

Using raytracing to derive the expected performance of STELLA's SES-VIS spectrograph

The visual STELLA echelle spectrograph (SES-VIS) is a new instrument for the STELLA-II telescope at the Izaña observatory on Tenerife. Together with the original SES spectrograph - which will still be used in the near IR - and a new H&K-optimized spectrograph, which is currently in the design phase, it will extend the capabilities of STELLA with the follow up of planetary candidates from space missions (TESS, PLATO2). SES-VIS is optimized for precise radial velocity determinations and long term stability. We have developed a ZEMAX based software package to create simulated spectra, which are then extracted using our new data reduction package developed for the PEPSI spectrograph. The focus in this paper has been put on calibration spectra, and the full range of available calibration sources (flat field, Th-Ar, and Fabry-Perot etalon), which can be compared to actual commissioning data once they are available. Furthermore we tested for the effect of changes of the environmental parameters to the wavelength calibration precision.

astro-ph.IM↗

arXiv2020

Second generation spectroscopic instrumentation for the STELLA robotic observatory

The current STELLA Echelle spectrograph (SES), which records 390nm to 870nm in one shot at a spectral resolution of 55000, will be replaced by a suite of specialized spectrographs in three spectral bands. The UV will be covered by a newly designed H&K spectrograph covering 380nm to 470nm (SES-H&K), the visual band (470nm - 690nm) will be covered by SES-VIS, which is a vacuum-stabilized spectrograph designed for high radial-velocity accuracy, and the NIR will be covered by the current SES spectrograph from 690nm to 1050nm. In order to improve the UV transmission, and to accommodate three different fibre-feeds, the prime focus corrector of the telescope will be refurbished, leading to an optical system with the f/2 1200mm spherical primary, a 4-lens collimator with 2 arcsec aperture, atmospheric dispersion corrector (ADC), and two dichroic beam splitters, feeding 3 separate fibre feeds for the three bands. The newly designed H&K spectrograph will be an Echelle spectrograph, based on a R4-grating with 41.6 l/mm and 110mmx420mm, using a f/5 camera and the cross-disperser in double pass (as in TRAFICOS, MIKE, KPF), using 21 spectral orders. The spectral resolution of all three spectrographs will be comparable to the 55000 of the current SES.

astro-ph.IM↗