Towards millimagnitude Photometry at the Vera Rubin Observatory: Aerosol Monitoring with Quadband Dispersed Imaging

TL;DR

This paper presents a method for monitoring atmospheric aerosols using multiband dispersed imaging at the Vera Rubin Observatory, aiming to improve millimagnitude photometry by accounting for atmospheric transmission variations.

Contribution

It introduces a novel observational approach with a multiband filter and disperser to track atmospheric aerosol variations affecting photometric precision.

Findings

Detected temporal variations in atmospheric extinction across four spectral bands.

Observed extinction differences exceeding 5 mmag/airmass between red and blue bands.

Demonstrated the potential for precise atmospheric transmission modeling to enhance photometric accuracy.

Abstract

As the frontier of precision astronomical photometry continues to advance, correcting for time-variable atmospheric transmission becomes increasingly important. We describe an observational approach to monitoring optical attenuation due to atmospheric aerosols, using a multiband filter and disperser on the Auxiliary Telescope at the Vera C. Rubin Observatory. This configuration allows us to perform simple aperture photometry on four notched-out spectral regions, covering 347 to 618 nm. We see clear evidence of temporal variations in extinction across these bands, which we attribute to variation in the aerosol content of the atmosphere above the observatory. The observed differences in extinction between the reddest and bluest band can exceed 5 mmag/airmass, highlighting the importance of including variable aerosols in the transmission of the atmosphere. We aspire to using precise determinations of the optical transmission of the atmosphere to enable a forward-modeling approach to achieving mmag photometric precision with Rubin data.