Venus at 1.7 micron
This false-colour view of Venus's night side is the composite of three infrared images acquired by the VIRTIS instrument on board Venus Express on 22 July 2006. The three images were taken with a time interval of about 30 minutes between them and from a distance of about 65 000 kilometres over the planet's surface.
The images show the observed radiation at a wavelength of 1.7 μm, revealing the thermal radiation emitted from about 15-20 kilometres altitude. In the selected colour-scheme brighter colours correspond to more intense radiation. The bright regions reveal areas of less cloud cover, where radiation from the surface can more easily escape.
Due to the high rotation speed and the highly dynamic nature of the Venus cloud cover, the images don't match on the borders as the cloud structure has changed noticeably in the 30-minute interval between adjacent images.
By taking the negative of these images, the cloud cover over Venus's night side can be visualised. In the negative picture, the bright regions now correspond with thicker cloud cover. An example of this is under the related images.