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Skylight does not control the imaging operations of Sentinel-2, and provides vessel detections as bonus data from standard images. Schedules of upcoming acquisitions are publicly accessible here: https://sentinels.copernicus.eu/web/sentinel/missions/sentinel-2/acquisition-plans Please note that Sentinel-2A and Sentinel-2B acquisitions are shared as separate KML files.
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Other strange optical phenomena might occur with bright sunlight, reflections, icy clouds, that because of satellite and ocean surface motion, will produce bright rainbow effects that catch the model’s attention, but should be fairly recognizable as not vessels to human eyes.
Aircraft
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Sentinel-2 uses a “push broom” sensor with a refracting mirror which causes a slight delay in the time certain color channels are captured and arrive at the sensor. While this is typically not noticeable with stationary or slow-moving objects, the altitude of the aircraft, movement of the aircraft, and movement of the satellite all work together to separate the red, green, and blue separation of the aircraft detected in the image, as seen below.
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Plankton, currents, and litter windrows are sometimes visible and detected in Sentinel imagery.
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Specular Reflection
Currently, the model can generate false positives from specular reflection off the ocean surface when alignment is right to reflect sunlight directly into the sensor. Large scale ocean features, such as the curvature of the earth, internal waves, upwelling, and ground swells cause a break-up of the sunlight reflection.
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More information and examples can be found here:
https://earthobservatory.nasa.gov/images/81814/ocean-revealed
https://earthobservatory.nasa.gov/images/84333/the-science-of-sunglint