First Images From NASA's SPHEREx

Figure A


Figure B

Click on images for larger versions

Some of the first images from NASA's SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) mission were captured March 27, 2025. Although the new images are uncalibrated and not yet ready to use for science, they give a tantalizing look at SPHEREx's wide view of the sky. Each bright spot is a source of light, like a star or galaxy, and each image is expected to contain more than 100,000 detected sources.

There are six images in every SPHEREx exposure – one for each detector. The top three images show the same area of sky as the bottom three images; this is the observatory's full field of view, a rectangular area about 20 times wider than the full Moon. When the SPHEREx observatory begins routine science operations in April, it will take approximately 600 exposures every day.

SPHEREx detects infrared light, which is invisible to the human eye. To make the images shown here, science team members assigned a visible color to each infrared wavelength captured by the observatory. With each detector capturing 17 unique infrared wavelength bands, there are 102 hues in this image.

To detect so many infrared colors, SPHEREx uses color filters set on top of the detectors. (If the detectors are like SPHEREx's eyes, the filters are like color-tinted glasses). A standard color filter blocks all wavelengths but one, but the SPHEREx filters are more like rainbow-tinted glasses, in that the wavelengths they block change gradually from the top of the filter to the bottom.

The legend at the top shows that the detectors are placed to observe infrared wavelengths from shortest to longest. Certain chemical elements are visible at specific wavelengths, as is the case with helium from Earth's atmosphere, which creates a bright line in the wavelength at the top of the top-left image.

Breaking down color this way can reveal the composition of an object or the distance to a galaxy. With that data, scientists can study topics ranging from the physics that governed the universe less than a second after its birth to the origins of water in our galaxy.

Figure A is an annotated version of the exposure with two insets (right) that give zoomed-in views of one of the images, further illustrating the high volume of sources the mission was designed to observe.

Figure B is the exposure in grayscale (without a visible color assigned to each infrared wavelength captured by the observatory). Some objects appear fainter in the lower three images, but this is only because of the brightness scale, which was chosen for visual appearance, and the images are uncalibrated.

The SPHEREx mission is managed by NASA's Jet Propulsion Laboratory for the agency's Astrophysics Division within the Science Mission Directorate at NASA Headquarters. BAE Systems (formerly Ball Aerospace) built the telescope and the spacecraft bus. The science analysis of the SPHEREx data will be conducted by a team of scientists located at 10 institutions in the U.S., two in South Korea, and one in Taiwan. Data will be processed and archived at IPAC at Caltech. The mission's principal investigator is based at Caltech with a joint JPL appointment. The SPHEREx dataset will be publicly available at the NASA-IPAC Infrared Science Archive. Caltech manages JPL for NASA.

For more about SPHEREx, visit: https://science.nasa.gov/mission/spherex/