A high precision polarimeter for small telescopes

TL;DR

Mini-HIPPI is a lightweight, high-precision polarimeter designed for small telescopes, capable of measuring stellar polarization at levels of 10^{-5} with applications demonstrated on bright stars and binary systems.

Contribution

This paper introduces Mini-HIPPI, a compact and sensitive polarimeter using FLC technology, suitable for small telescopes and capable of high-precision polarization measurements.

Findings

Measurements of standard stars match predicted polarization levels.

Bright star polarization measurements agree with other high-sensitivity polarimeters.

Detected polarization variability in the binary system Spica.

Abstract

We describe Mini-HIPPI (Miniature HIgh Precision Polarimetric Instrument), a stellar polarimeter weighing just 650 grams but capable of measuring linear polarization to $\sim10^{-5}$. Mini-HIPPI is based on the use of a Ferroelectric Liquid Crystal (FLC) modulator. It can easily be mounted on a small telescope and allows study of the polarization of bright stars at levels of precision which are hitherto largely unexplored. We present results obtained with Mini-HIPPI on a 35 cm telescope. Measurements of polarized standard stars are in good agreement with predicted values. Meaurements of a number of bright stars agree well with those from other high-sensitivity polarimeters. Observations of the binary system Spica show polarization variability around the orbital cycle.