The Carnegie Observatories System for MultiObject Spectroscopy


·      COSMOS3 is substantially different from previous versions. If you have previously used COSMOS, you should begin by reading Moving to COSMOS3.

·      Beginning with version Monterey 12.3, Mac OS no longer includes the python support needed to run programs defineobs, adjust-mask, editpar, whatsthat, display, fitsheader, and mark-slits. To restore this functionality:

Download the file   cosmos3python.tgz    from   and place in your root COSMOS3 directory, then:

tar -xzvf



1.    Introduction

2.    Data Files

3.    Programs

4.    Using the software


6.    Installing and running COSMOS

7.    Writing routines for COSMOS

8.    COSMOS Cookbook

9.    Frequently Asked Questions

10. Moving to COSMOS3

11. History


Version: 3.00
Date: 2018-05-06
A. Oemler, K. Clardy, D. Kelson, G. Walth, and E. Villanueva