Measurement of telescope transmission using a Collimated Beam Projector

TL;DR

This paper introduces the Collimated Beam Projector (CBP), a device designed to precisely measure telescope transmission and filter characteristics, aiming to reduce systematic uncertainties in supernova flux calibration for dark energy studies.

Contribution

The paper presents the design and initial results of the CBP, a novel instrument for high-precision measurement of telescope transmission to improve dark energy parameter estimation.

Findings

CBP can measure filter transmissions with high precision.

Initial results demonstrate the effectiveness of CBP in the StarDice experiment.

Improved transmission measurements can enhance dark energy parameter accuracy.

Abstract

The number of type Ia supernova observations will see a significant growth within the next decade, especially thanks to the Legacy Survey of Space and Time undertaken by the Vera Rubin Observatory in Chile. With this rise, the statistical uncertainties will decrease and the flux calibration will become the main uncertainty for the characterization of dark energy. The uncertainty over the telescope transmission is a major systematic when measuring SNe Ia colors. Here we introduce the Collimated Beam Projector (CBP), a device that can measure the transmission of a telescope and its filters. Composed of a tunable monochromatic light source and optics to provide a parallel output beam this device is able to measure with high precision the filter transmissions. In the following, we will show how measuring precisely a telescope transmission can also improve the precision of the dark energy parameters. As an example, we will present the first results of the CBP in the context of the StarDice experiment.