# BRITE-Constellation: Data processing and photometry

## TL;DR

This paper presents data processing pipelines for the BRITE nano-satellite mission, demonstrating high-precision photometry capabilities and comparing two observing modes, with chopping mode outperforming stare mode over time.

## Contribution

The paper introduces two new pipelines for high-precision photometry from BRITE satellites and evaluates their performance, highlighting the advantages of the chopping mode for long-term observations.

## Key findings

- Chopping mode yields better photometry than stare mode after 2.5 years.
- The pipelines effectively handle high impulsive noise in space-based images.
- Chopping mode significantly improves data quality in long-term space photometry.

## Abstract

The BRITE mission is a pioneering space project aimed at the long-term photometric monitoring of the brightest stars in the sky by means of a constellation of nano-satellites. Its main advantage is high photometric accuracy and time coverage inaccessible from the ground. The main aim of this paper is the presentation of procedures used to obtain high-precision photometry from a series of images acquired by the BRITE satellites in two modes of observing, stare and chopping. We developed two pipelines corresponding to the two modes of observing. The assessment of the performance of both pipelines is presented. It is based on two comparisons, which use data from six runs of the UniBRITE satellite: (i) comparison of photometry obtained by both pipelines on the same data, which were partly affected by charge transfer inefficiency (CTI), (ii) comparison of real scatter with theoretical expectations. It is shown that for CTI-affected observations, the chopping pipeline provides much better photometry than the other pipeline. For other observations, the results are comparable only for data obtained shortly after switching to chopping mode. Starting from about 2.5 years in orbit, the chopping mode of observing provides significantly better photometry for UniBRITE data than the stare mode. This paper shows that high-precision space photometry with low-cost nano-satellites is achievable. The proposed meth- ods, used to obtain photometry from images affected by high impulsive noise, can be applied to data from other space missions or even to data acquired from ground-based observations.