Authors: Pashkovskii V. E., Karpikov S. R. (the “StealthTransit” Initiative)

Title: An effective solution for the active prevention of light interference from satellites and aircraft trails in optical astronomy

Abstracts: 

With the growing number of satellites in low Earth orbit (LEO) and plans by Russian and international companies to launch tens of thousands of new spacecraft, the problem of satellite trails in astronomical images and the resulting significant loss of scientific data when such trails overlap the target fields has become increasingly urgent.

We propose and describe the implementation of the StealthTransit system. It is a technology and a practical new tool for reducing the impact of such interference. Unlike other methods of mitigating the effect of satellites on optical astronomy which require changes to satellite design (reduced reflectivity, sunshades, size reduction) StealthTransit operates on the telescope side and very efficiently eliminates light trails both from satellites across a wide brightness range and from other bright objects, such as aircraft. A key advantage of the StealthTransit approach over digital post-processing removal of trails is the minimal loss of scientific data.

StealthTransit is most effective on telescopes with narrow and medium fields of view. Protecting observations on wide-field telescopes will be effective in local areas of the image. It is also currently the only method that provides protection against satellite interference for low- and medium-resolution spectroscopy.

The StealthTransit system uses a fast-active shutter that briefly closes at the moment a satellite crosses the field of view, preventing sunlight reflected from the satellite from reaching the camera sensor. At the same time, the sensor continues integrating, which minimizes data loss and eliminates the readout noise associated with interrupting and resuming exposures. A separate auxiliary detector telescope provides highly accurate trajectory and timing information for satellite transits, exceeding the accuracy of standard Two-Line Element sets (TLEs).

StealthTransit is a practical, patented system that can be integrated quickly and without significant cost into existing astronomical observing facilities.

The active-shutter application described in this report has been recognized by the International Astronomical Union (IAU) and NOIRLab as one of the principal methods for mitigating the impact of low-orbit satellites on astronomy over the next decade.

The authors express their gratitude to the Caucasus Mountain Observatory of the Sternberg Astronomical Institute, Lomonosov Moscow State University, and personally to N. I. Shatsky for scientific support.