The SHOES team used Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Advanced Camera for Surveys (ACS) to observe 240 Cepheid variable stars across seven galaxies.

Data from Hubble's near-infrared camera and multi-object spectrometer revealed the presence of the molecules, and data from Spitzer's photometer and infrared spectrometer measured their amounts.

Each unit houses a near-infrared (NIR) LED and monochrome CCD camera sensor, so as the red pigment in blood (hemoglobin) absorbs NIR light, veins appear as dark lines on the resulting image.