Impact on Astronomy Measured: It’s time for Starlink to show its worth

Pamela L. Gay, Ph.D.
3 min readJan 19, 2022

While I recognize a lot of people have returned to a more normal life now that we have vaccines, I have to admit I’m one of the high-risk individuals who is still not really leaving my house. This means, my world has become: the before times; the infinite Blursdays of plague-times; and a question mark of a future as I wonder how much different the post-covid world is going to be. In many ways, the world has just gone on, unobserved by the likes of me.

The streak from a Starlink satellite appears in this image of the Andromeda galaxy, taken by the Zwicky Transient Facility, or ZTF, during twilight on May 19, 2021. The image shows only one-sixteenth of ZTF’s full field of view. Credit: Caltech Optical Observatories/IPAC

One of the weird leaps the world is making is toward a sky filled with low-earth orbit satellites. In early 2020, at the last face-to-face American Astronomical Society meeting, folks highlighted the potential social good and astronomical horror of the still novel Starlink satellites. We all wrote our think pieces, and then went home to experience a pandemic.

I have to admit that not nearly as much energy has gone into worrying about these tiny craft as might have been expended if we were actively hosting star parties, supporting observing sessions with students, or otherwise going out to observe the now interrupted sky.

While many of us have literally stayed home, survey telescopes have continued their largely-robotic missions to seek out the things that flicker, flare, and move in the night. One particularly successful scope, the Palomar Zwicky Transient Facility, has been doing its best to alert us to scientifically awesome supernovae, and… in a new paper in ApJL, to the scientifically disturbing Starlink satellites. In this paper, led by Przemek Mróz, researchers document the ever increasing impact of Starlink satellites on their images.

According to Mróz, “In 2019, 0.5 percent of twilight images were affected, and now almost 20 percent are affected.”

This is where I need to let you know, the kinds of asteroids astronomers are most worried about — the ones that could hit us — are the kind we are most likely to discover in the twilight sky near the Sun. Those twilight images are important.

The reason only twilight images are affected by the Starlink satellites is because the current craft are so low in their orbits that they are in the Earth’s shadow about the time twilight ends for those of us on Earth. Missions in much higher…



Pamela L. Gay, Ph.D.

Astronomer, technologist, & creative focused on using new media to engage people in learning and doing science. Opinions & typos my own.