4MOST is a wide-field, high-multiplex, fibre-fed spectrograph, which will be mounted on the ESO VISTA telescope. High- and low-redshift surveys, targeting stars, galaxies, and AGN, can be executed in parallel, populating all the available 2436 fibers. Here, we present the 4MOST calibration plan, concentrating on the unique features dictated by the design of the instrument. These include the night-time backillumination of the fibers for precise metrology, simultaneous calibrations by dedicated fibers, attached night-time flatfield and wavelength calibration via a laser driven light source with a Fabry Perot etalon (FPE) on a moving carriage, and the observations of benchmark, telluric, and radial velocity standards for the science cross-calibration between 4MOST and complementary surveys from other telescopes.
4MOST is a new high-multiplex, wide-field spectroscopic survey facility under construction for ESO's 4m-VISTA telescope at Paranal, Chile. Its key specifications are: a large field of view of 4.4 square degrees, a high multiplex fibre positioner based on the tilting spine principle that positions 2436 science fibres in the focal surface of which 1624 fibres go to two low-resolution optical spectrographs (R = λ/Δλ ~ 6500) and 812 fibres transfer light to the high-resolution optical spectrograph (R ~ 20,000). Currently, almost all subsystems are completed and full testing in Europe will be finished in spring 2023, after which 4MOST will be shipped to Chile. An overview is given of instrument construction and capabilities, the planned science of the consortium and the recently selected community programmes, and the unique operational scheme of 4MOST.
The 4-metre Multi-Object Spectroscopic Telescope (4MOST) is a new high-multiplex, wide-field spectroscopic survey facility under development for the Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal. Its key specifications are: a large field of view (FoV) of 4.4 square degrees and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs (R =6500), and 812 fibres transferring light to the high-resolution spectrograph (R ≈ 20000). For the end-to-end characterization of the 4MOST facility, we analyze the impact of the atmosphere at Paranal, VISTA telescope, wide field corrector, atmospheric dispersion compensator, tilting spine positioner, fibre system, spectrographs and detector systems. We present an exhaustive analysis of the most influential characteristics on the transmission efficiency for a 4MOST observation. Many environmental, telescope, and instrumental effects can be characterized in isolation, such as glass transmission. But there are also many effects that are caused by a combination of multiple components. For example, the residual atmospheric dispersion in combination with fibre positioning errors; or the fibre field position in combination with fibre tilt angle as well as the fibre focus position. To capture this complexity, we present a coherent quantitative assessment of each significant individual effect, as well as a relevant selection of effect combinations. To quantify the impact on the survey nature of the 4MOST instrument, we also introduce parts of the optical performance simulator TOAD, which was used to compute the impact each effect.
A status overview of 4MOST is presented, a new high-multiplex, wide-field spectroscopic survey facility under construction for ESO's VISTA telescope at Paranal. Its key specifications are: a large field of view of 4.4 deg2 and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs (R = λ/Δλ ~ 6500), and 812 fibres transferring light to the high-resolution spectrograph (R ~ 20 000). The 4MOST system integration has commenced and the selection process for ESO community survey programmes has been started. This overview presents the expected performance of the instrument, the science the consortium expects to carry out, and the unique operational scheme of 4MOST.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.