# Phase III of USO Solar Vector Magnetograph

## TL;DR

This paper describes the third development phase of the USO Solar Vector Magnetograph, highlighting key upgrades like a new guiding system, high-cadence spectropolarimetry, and expanded spectral line observations for improved solar magnetic field measurements.

## Contribution

It introduces three major improvements in the instrument's design and capabilities, enhancing solar magnetic field observations and chromospheric studies.

## Key findings

- Successful implementation of a web-camera based guiding system
- High-cadence spectropolarimetry achieved with Liquid Crystal Variable Retarders
- Inclusion of Na D1 line for chromospheric observations

## Abstract

The Solar Vector Magnetograph (SVM) is a modern imaging spectropolarimeter installed at Udaipur Solar Observatory (USO). Earlier phases saw the development of the instrument using off-the-shelf components with in-house software development. Subsequently, improvements were done in the opto-mechanical design of the sub-systems and the telescope tracking system. The third phase of the instrument development saw three major improvements, these include: (i) installation of a web-camera based telescope guiding system, developed in-house, (ii) high-cadence spectropolarimetry using Liquid Crystal Variable Retarders and a fast CCD camera and (iii)inclusion of Na D1 line with regular photospheric Fe 630.2 nm line for chromospheric observations.