- On April 8, millions of people across Mexico, the United States and Canada will have the chance to see a total solar eclipse.
- There is enormous public interest in viewing the eclipse: revenue from tourism is expected to top US$1 billion, comparable to the Super Bowl.
Bright satellites in the night sky
- Currently, there are over 9,500 functional satellites in orbit, fully 60 per cent of which are Starlink satellites launched in the past five years.
- These 5,700 Starlink satellites are bright and most are visible to the naked eye anytime they are sunlit and high in an observer’s night sky.
How bright are satellites during a total eclipse?
- The brightness of satellites during the eclipse depends most strongly on how close the satellites are to observers on the ground.
- In our simulation, we found that all satellites visible in the sky during the eclipse are inside the moon’s shadow, making them fainter than they would be otherwise.
When all these effects are taken into account, we predict the brightest satellites would be visible to the naked eye from a fully dark location. But during an eclipse, the sky is not very dark — it is even brighter than the night sky during a full moon, making only the brightest stars visible. For this reason, we do not expect these satellites to be visible as “moving stars”.
Satellite glints are becoming more common
- Glints are short, bright reflections from large, flat surfaces on satellites and tumbling, abandoned rocket bodies.
- Our brightness model uses a simple sphere for predicting satellite brightnesses, which does a reasonable job of reproducing the overall brightness distribution, but does not include glints.
- Predicting glints requires knowing the exact shape and orientation of each satellite, which most megaconstellation operators consider proprietary and do not share with anyone outside their corporations.
Documenting the eclipse
- If you think you saw some satellites, either as a moving star or as a short glint, let us know.
- A timer would be ideal, so you can let the camera record the sky while you focus on enjoying the eclipse.
- Read more:
Photographing the eclipse?
Satellites are changing the sky, worldwide
- Satellites are changing every aspect of stargazing and astronomy research, as well as polluting the atmosphere and threatening the future use of Earth orbits.
- If you are fortunate to be along the path of the April 2024 eclipse, go out and enjoy it.
Samantha Lawler receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC). Aaron Boley receives Canadian tri-agency funding and is a Canada Research Chair in planetary astronomy. He is the co-director of the Outer Space Institute. Hanno Rein receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC).
