MOTHRA telescope in Chile aims to reveal faint cosmic web structures

Yesterday 11:20

By: Dakir Madiha

MOTHRA telescope in Chile aims to reveal faint cosmic web structures

A new astronomical instrument under construction in the mountains of Chile is set to become the largest lens based telescope array ever built. Known as MOTHRA, the Modular Optical Telephoto Hyperspectral Robotic Array will combine 1,140 Canon telephoto lenses to observe extremely faint structures in the universe.

The project is being built at the Obstech El Sauce Observatory in the Rio Hurtado valley in Chile. Its creators announced Tuesday that the telescope is currently under construction and is expected to be fully operational by the end of 2026.

MOTHRA is led by astronomer Pieter van Dokkum of Yale University and Roberto Abraham of the University of Toronto. The instrument is being developed through Dragonfly FRO, a focused research organization launched in January 2025 to pursue ambitious scientific projects.

The telescope’s main goal is to detect the faint glow of ionized gas that exists between galaxies. These signals trace the cosmic web, a vast structure of gas and dark matter that connects galaxies across the universe.

The array will work by digitally combining images captured by its 1,140 lenses. Together, they will achieve the light collecting power equivalent to a single lens with a diameter of 4.7 meters. The system will consist of 30 large fork mounts, each carrying 38 telephoto lenses equipped with narrow band filters designed to isolate the weak light emitted by hydrogen gas.

Van Dokkum said the telescope was designed to maximize discovery potential for faint intergalactic gas. By combining a large effective aperture, a wide field of view, and tunable ultra narrow band filters, the instrument will open a new observational window for studying the universe.

The design builds on the earlier Dragonfly Telephoto Array in New Mexico, also created by van Dokkum and Abraham. That system uses 48 lenses and has already demonstrated the approach by revealing extremely faint galaxies and stellar structures previously invisible to astronomers. MOTHRA expands this concept dramatically.

Funding for the telescope comes from Alex Gerko, founder and chief executive of the algorithmic trading firm XTX Markets. Gerko has previously supported other astronomy projects, including the Argus Array at the University of North Carolina.

The project also illustrates a different approach to organizing scientific research. Dragonfly FRO operates as a Focused Research Organization, a model developed by the nonprofit Convergent Research that applies startup style structures and timelines to large scientific challenges.

Abraham said the telescope takes advantage of recent advances in optics, detectors, and computing power to explore the universe in new ways, describing the instrument as entirely unique among existing telescopes.