A Russian startup is testing a technology that filters Starlink using astronomical observations.

A Russian start-up is testing a technology that filters out the disturbing passages of SpaceX's Starlink satellites from astronomical observations.

Developed by St. Petersburg, based in Russia's Stealth Transit, the technology detects brilliant satellites approaching and shuts down the telescope shutter to prevent the spaceship from ruining the image.

In a statement emailed to Space.com, the company said the technology works with the narrow and medium field of view telescopes, both professional and amateur, that cover no more than one square degree of the sky. Broader fields of view might be affected by several satellites at a time, making this solution impractical, Stealth Transit said in the statement.

However, the company's CEO, former telecom engineer Vlad Pashkovsky, told Space.com that a large field of vision telescopes, such as the Vera C. The Rubin Observatory in Chile, which has a 9.6 square degree field of vision, could still benefit partly from this technology.

"The StealthTransit approach enables us to protect certain areas from a wider field of vision, those that are most important for observation," Pashkovsky says.

The company recently began testing the technology in one of Russia's most advanced astronomical observatories, the Caucasus Mountain Observatory near Kislovodsk, in southwestern Russia.

The team installed its detector of bright satellites on an ASA 600 telescope that has a field of view of 22 by 22 arcminutes (one arcminute is one-sixtieth of a degree) and connected the detector to a Stealth Transit active shutter.

"The Stealth Transit detector recognizes the trajectories of satellites in low Earth orbit and accurately predicts the transit time of the satellite across the telescope's field of view," said Mr. Pashkovsky. "The shutter stops the display of the astronomical camera to make the satellite transit invisible."

Astronomers have deplored the undesirable visual effects of Starlink satellites since SpaceX began to launch the first batches of its constellation scheduled for 2019. Traveling around the Earth at an altitude of 340 miles (550 kilometers), the satellites reflect the light of the sun and create trails in astronomical images. They also increase luminous pollution in regions that are known for otherwise perfect conditions to observe the stars. The large and costly international observatories located on these sites are therefore likely to have fewer useful observation windows and decrease returns on investment.

Earlier this year, The International Astronomical Union (IAU) initiated talks within the United Nations' Committee on the Peaceful Uses of Outer Space (UN COPUOS) to protect the pristine night sky as human heritage.

SpaceX has already said that they will work with astronomers to find a solution, but what has been done to date has been considered inadequate by the scientific community. One of the solutions proposed by SpaceX was to cover the satellites with non-reflecting material to reduce brightness. But Stanislav Karpikov, chief technical officer of StealthTransit, said in the statement that satellite brightness is mostly determined by the orientation of its reflective parts, for example, solar arrays, relative to Earth and the sun.

Pashkovsky added that gradation coatings tend to affect the thermal equilibrium of satellites and thus reduce their longevity.

"The reduction in brightness conflicts with the targets of ensuring the performance and longevity of the satellite,' said Mr. Pashkovsky. "The use of dimming coatings disturbs the thermal balance of the satellite and reducing the area of solar arrays or changing their orientation deprives the satellite of necessary energy." However, he added that eventually, satellites will become less bright as they become more compact.

Starlink satellites cause the most significant disturbance shortly after launch when they move in train-shaped formations when ejected from the rocket fairing. They end up scattering as they reach their operational orbits, but remain visible even with relatively simple telescopes.

UN COPIOUS estimates that up to 40% of astronomical observations with large-field telescopes could be ruined after the deployment of all 12,000 satellites currently scheduled by SpaceX. The company is considering up to 40,000 satellites in the far future. SpaceX did not respond to a response.

Nikolay Shatsky, the head of the Caucasian Mountain Observatory, which is testing the Stealth Transit tech, said Starlink affects even narrow field of view telescopes, especially when they search for near-Earth asteroids and comets during twilight hours.

"The risk of image damage increases with the release of dozens of new LEO satellites every month,' said Shatsky in his statement. "The risk factor we estimate is a minimum of 5%. Such images cannot be corrected even with a process. You have to find open windows in the observatory calendar to perform repeated observations."

However, he said, there is no guarantee that repeated comments will be unaffected.