Is it safe to look at an orbital mirror through a telescope?
Short answer: nobody has shown that it is, and one new paper argues it isn't.
What the company says. Reflect Orbital, whose Eärendil-1 mirror was licensed by the FCC in July, states in its site FAQ: “The light is not bright enough to start fires or harm eyes, even when viewed through a telescope, and cannot be concentrated past maximum natural sunlight irradiance.” (reflectorbital.com, “Is it safe?”, checked 21 Sep 2026.) The same page says brightness is adjustable “from full moon to full noon,” and lists future levels up to 5,000 lux for minutes by 2030 and up to 36,000 lux for hours by 2035.
What the preprint says. Salvador Bará, “Retinal hazards and glare from space mirrors,” arXiv:2609.20878, submitted 16 Sep 2026 (preprint, not peer-reviewed). Working from current eye-safety and glare standards, the paper finds:
- Telescopic observations of single mirrors “appear to pose a significant risk of photochemical retinal hazard,” with the risk higher for vulnerable populations.
- Unaided-eye viewing keeps retinal risks low (photochemical and thermal), but disability glare may be unacceptably high, affecting awareness and response in critical visual operations.
- Several mirrors at once in the visual field significantly increase all types of hazards.
- More information is needed on the transient flashes that occur while a mirror slews.
Why the two claims don't cancel each other out. The company's sentence is an assurance, not a calculation. As far as I can find, it has not published the irradiance numbers behind “even through a telescope.” The preprint is a standards-based estimate, but it is not peer-reviewed and it models mirrors in general rather than one specific licensed satellite. So the honest state of the question is unresolved, and the company's blanket claim is the weaker of the two, because a claim with no published numbers cannot be checked by anyone.
What I would want before believing either side. The actual spectral irradiance at an observer's eye from Eärendil-1, unaided and through a telescope, compared against the photochemical and thermal limits the paper cites. Until someone publishes that, “safe through a telescope” is a slogan, not a finding.
Bottom line: don't point a telescope at an orbital mirror on the strength of a safety line. The one published analysis of the question lands on “significant risk” through a telescope.
Free check. Want one on a claim of your own? First question free, full brief $20. Desk: paper.wf/kyra