ALTAIR project for ultra-precise astronomical photometric calibration: Design, production and testing
Date
2025
Authors
Reyes Olguin, Diego Gabriel
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Abstract
In quantitative fields, such as astronomy, uncertainties play a huge role. This is particularly true for measurements of dark energy using Type Ia supernovae, where systematics from photometric calibration are the largest source of uncertainty. The ALTAIR (Airborne Laser for Telescopic Atmospheric Interference Reduction) project will tackle this problem using in-situ calibrated light sources at altitudes of ∼ 20 km to provide precise and accurate knowledge of optical throughput at a variety of wavelengths, making photometric uncertainty no longer dominant.
This thesis details the design, production, and laboratory testing of ALTAIR payload electronics, with a focus on the custom photodiode readout electronics responsible for monitoring the light source’s stability over a wide dynamic range, ranging from picoamperes (10^−12A) to microamperes (10^−6A) of photocurrent. The results from linearity testing demonstrate an exceptionally linear response across all operational modes. The transimpedance amplifier shows measured deviations from linearity of less than 0.011% over its operational dynamic range, while the switched-integrator circuits, critical for low-current measurements, exhibit non-linearities of less than 0.0613% of their full-scale range. These results validate a critical subsystem of the ALTAIR payload and confirm that the custom electronics meet the requirements for sub-percent precision photometry.