Black Image = ISS is on the night side of the Earth. 
Image of sunset with words displayed = Switching between cameras, or communications with the ISS is not available.
Please note: The HDEV cycling of the cameras will sometimes be halted, causing the video to only show select camera feeds. This is handled by the HDEV team, and is only scheduled on a temporary basis. Nominal video will resume once the team has finished their scheduled event.

The High Definition Earth Viewing (HDEV) experiment aboard the ISS was activated April 30, 2014. It is mounted on the External Payload Facility of the European Space Agency’s Columbus module. This experiment includes several commercial HD video cameras aimed at the Earth which are enclosed in a pressurized and temperature controlled housing. While the experiment is operational, views will typically sequence through the different cameras. Between camera switches, a gray and then black color slate will briefly appear. To learn more about the HDEV experiment, visit here.