PICSARR: high-precision polarimetry using CMOS image sensors

TL;DR

PICSARR is a compact, cost-effective astronomical polarimeter utilizing CMOS sensors, capable of high-precision polarization measurements across a wide wavelength range on small telescopes.

Contribution

This work introduces a high-performance polarimeter based on CMOS image sensors, suitable for small telescopes, with demonstrated high-precision capabilities and broad wavelength coverage.

Findings

Achieved high-precision polarization measurements on small telescopes.

Demonstrated broad wavelength range from UV to near-infrared.

Showcased potential for studying polarization variability in stars and planets.

Abstract

We have built and tested a compact, low-cost, but very-high-performance astronomical polarimeter based on a continuously rotating half-wave plate and a high-speed imaging detector. The polarimeter is suitable for small telescopes up to ~1 m in aperture. The optical system provides very high transmission over a wide wavelength range from the atmospheric UV cutoff to ~1000 nm. The high-quantum-efficiency, low-noise and high-speed of the detectors enable bright stars to be observed with high-precision as well as polarization imaging of extended sources. We have measured the performance of the instrument on 20 cm and 60 cm aperture telescopes. We show some examples of the type of science possible with this instrument. The polarimeter is particularly suited to studies of the wavelength dependence and time variability of the polarization of stars and planets.