Preliminary design of the Visible Spectro-Polarimeter for the Advanced Technology Solar Telescope

TL;DR

The paper presents the preliminary design of the ViSP instrument for the ATST, a high-resolution spectro-polarimeter capable of simultaneous multi-wavelength solar observations with advanced polarization measurement features.

Contribution

It introduces the design specifications and capabilities of the ViSP instrument, including its spectral range, resolution, and automation features, for solar magnetic field studies.

Findings

Design achieves 0.04 arcsec spatial resolution

Spectral resolving power of 180,000 across all focal planes

Supports up to 4 diffraction gratings for flexible observations

Abstract

The Visible Spectro-Polarimeter (ViSP) is one of the first light instruments for the Advanced Technology Solar Telescope (ATST). It is an echelle spectrograph designed to measure three different regions of the solar spectrum in three separate focal planes simultaneously between 380 and 900 nm. It will use the polarimetric capabilities of the ATST to measure the full Stokes parameters across the line profiles. By measuring the polarization in magnetically sensitive spectral lines the magnetic field vector as a function of height in the solar atmosphere can be obtained, along with the associated variation of the thermodynamic properties. The ViSP will have a spatial resolution of 0.04 arcsec over a 2 arcmin field of view (at 600 nm). The minimum spectral resolving power for all the focal planes is 180,000. The spectrograph supports up to 4 diffraction gratings and is fully automated to allow for rapid reconfiguration.