# COCOA Code for Creating Mock Observations of Star Cluster Models

## TL;DR

COCOA is a new code that creates realistic mock observations from star cluster simulations, enabling direct comparison with actual photometric data to improve understanding of star cluster evolution.

## Contribution

The paper introduces COCOA, a novel tool for generating realistic synthetic observations from star cluster models, facilitating comparison with real telescope data.

## Key findings

- COCOA successfully simulates realistic observations of star clusters.
- It can recover photometric data comparable to actual telescope observations.
- The tool demonstrates potential for broad scientific applications in star cluster research.

## Abstract

We introduce and present results from the COCOA (Cluster simulatiOn Comparison with ObservAtions) code that has been developed to create idealized mock photometric observations using results from numerical simulations of star cluster evolution. COCOA is able to present the output of realistic numerical simulations of star clusters carried out using Monte Carlo or \textit{N}-body codes in a way that is useful for direct comparison with photometric observations. In this paper, we describe the COCOA code and demonstrate its different applications by utilizing globular cluster (GC) models simulated with the MOCCA (MOnte Carlo Cluster simulAtor) code. COCOA is used to synthetically observe these different GC models with optical telescopes, perform PSF photometry and subsequently produce observed colour magnitude diagrams. We also use COCOA to compare the results from synthetic observations of a cluster model that has the same age and metallicity as the Galactic GC NGC 2808 with observations of the same cluster carried out with a 2.2 meter optical telescope. We find that COCOA can effectively simulate realistic observations and recover photometric data. COCOA has numerous scientific applications that maybe be helpful for both theoreticians and observers that work on star clusters. Plans for further improving and developing the code are also discussed in this paper.