# Measuring a Charge-Coupled Device Point Spread Function: Euclid Visible Instrument CCD273-84 PSF Performance

**Authors:** Sami-Matias Niemi, Mark Cropper, Magdalena Szafraniec, Thomas Kitching  
**arXiv:** [1412.5382](https://arxiv.org/abs/1412.5382)  
**Date:** 2014-12-17  
**Summary page:** https://www.summarizepaper.com/en/paper/1412.5382v1/

## Key points

- The authors present a novel modelling technique for measuring the intrinsic Charge-Coupled Device (CCD) Point Spread Function (PSF) characteristics of a back-illuminated development Euclid Visible Instrument (VIS).
- Optical spot projection system and the CCD273-84 PSF are jointly modelled using Bayesian posterior probability density function sampling to all available data simultaneously.
- Characterisation of a CCD273-84 PSF as a function of wavelength and intensity reveals that the CCD PSF kernel size increases with increasing intensity and decreasing wavelength.
- This work has important implications for understanding the performance of CCDs in astronomical observations, particularly relevant for future space missions such as Euclid.
- Detailed simulations are included to demonstrate their approach which could be useful for other researchers working in this field.
- Overall, this paper presents an innovative method for characterising CCD PSFs that has broad applications in astronomy and beyond.

## Summary

In this paper, the authors present a novel modelling technique for measuring the intrinsic Charge-Coupled Device (CCD) Point Spread Function (PSF) characteristics of a back-illuminated development Euclid Visible Instrument (VIS). The optical spot projection system and the CCD273-84 PSF are jointly modelled using Bayesian posterior probability density function sampling to all available data simultaneously. This generative model fitting allows good parameter estimations even when data are not well sampled. The authors characterise a CCD273-84 PSF as a function of wavelength and intensity. They find that the CCD PSF kernel size increases with increasing intensity and decreasing wavelength. This work has important implications for understanding the performance of CCDs in astronomical observations and will be particularly relevant for future space missions such as Euclid. Detailed simulations are included to demonstrate their approach which could be useful for other researchers working in this field. Overall, this paper presents an innovative method for characterising CCD PSFs that has broad applications in astronomy and beyond.