This image of the sun taken with the Extreme Ultraviolet Imager onboard NASA's Solar Terrestrial Relations Observatory Ahead spacecraft, which collects images in several wavelengths of light that are invisible to the human eye. This image shows the sun in wavelengths of 171 angstroms, which are typically colorized in blue. STEREO-A has been on the far side of the sun since , where it had to operate in safe mode, collecting and saving data from its radio instrument.