June 24, 2026
The European Space Agency's Euclid mission has released a spectacular new view of the center of our Milky Way galaxy, revealing more than 60 million stars across an immense region of the galactic bulge. The image is defined by Euclid's sharp vision from space and its ability to capture a very large field of view in visible light. For this public release, color information was added using observations from the Canada-France-Hawaiʻi Telescope's MegaCam camera, obtained from Maunakea in Hawaiʻi during the summer of 2025. These CFHT observations provide optical color through the broad-band u, g, and r filters, broad-band filters that isolate colors from the near ultra-violet to the red, complementing Euclid's monochromatic visible-light image and helping bring this dense region of the Milky Way to life for the public.
Euclid was designed to map the distant Universe and study the hidden influence of dark matter and dark energy, unseen parts of the universe that we cannot observe directly, but that shape how galaxies move and how the universe expands. For this special observation, however, the space telescope turned toward one of the brightest and most crowded regions of the sky: the galactic bulge of our galaxy, the central region of the Milky Way. Euclid observed the field in early 2025 with its VIS instrument, producing a vast, high-resolution mosaic in visible light.
Because Euclid's galactic bulge observation used VIS alone, the original data are monochromatic. The color version released to the public combines Euclid's sharp space-based image with ground-based color information from CFHT-MegaCam. The result preserves the crispness of Euclid's view while using CFHT observations to distinguish the optical colors of stars and structures across the field.
"Euclid and CFHT each make an essential contribution. Euclid provides the sharp, wide-field view from space, while CFHT supplies the color information that supports the mission's science. This image is a striking illustration of how space- and ground-based observatories work together", said Jean-Gabriel Cuby, CFHT Executive Director.
"By combining Euclid's exquisite spatial resolution with CFHT's color data, we can create compelling views of the Galactic bulge that are both scientifically valuable and accessible to the public," added Jean-Charles Cuillandre, who led the CFHT observations and image processing of the color image.
The new image also illustrates a broader relationship between Euclid and ground-based astronomy. CFHT is a key partner in the Ultraviolet Near Infrared Optical Northern Survey, or UNIONS, a major imaging survey of the northern sky carried out with CFHT, the National Astronomical Observatory of Japan Subaru Telescope, and Pan-STARRS, the Panoramic Survey Telescope and Rapid Response System located at the nearby Haleakalā Observatory on Maui. Through UNIONS, CFHT-MegaCam provides optical imaging that supports Euclid's core cosmology mission conducted by the Euclid Consortium, including the ground-based color information needed to help characterize galaxies observed by the space telescope. Space-based images provide exquisite sharpness and stability, while ground-based observatories provide complementary color coverage. Together, these datasets help astronomers extract more complete information from the Universe, from the crowded stellar fields of our own Galaxy to the distant galaxies used to study dark matter and dark energy.
MegaCam, CFHT's wide-field optical imager, is particularly well suited to this kind of work. With a field of view of about one square degree, comparable in scale to a Euclid pointing, MegaCam can efficiently cover large areas of the sky and naturally match Euclid's 3 x 3 mosaic with a corresponding 3 x 3 set of color observations. Combined with the excellent observing conditions on Maunakea, this makes CFHT a powerful source of high-quality optical data.
CFHT is located on Maunakea, land of the Kānaka Maoli people, and a mountain of considerable cultural, natural, and ecological significance to Native Hawaiians. The use of observations from Maunakea in this Euclid release reflects the continuing role of Hawaiʻi-based astronomy in supporting major international space missions.
For more information, see ESA's full Euclid press release: ESA’s Euclid captures the Milky Way's crowded heart
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