Oberon (moon) up to 40 km and its temperature is around 180 K. However, the internal structure of Oberon depends heavily on its thermal history, which is poorly known at present. Oberon is the second-darkest large moon of Uranus after Umbriel. Its surface shows a strong opposition surge: its reflectivity decreases from 31% at a phase angle of 0° (geometrical albedo) to 22% at an angle of about 1°. Oberon has a low Bond albedo of about 14%. Its surface is generally red in color, except for fresh impact deposits, which are neutral or slightly blue. Oberon is, in fact, the reddest
Oberon (operating system) in the Microsoft Windows OS was called Plugin Oberon. The version called Oberon V4 (see also History) is closer to the original operating system developed by N. Wirth & J. Gutknecht. It was originally developed at ETHZ, but when H.P. Mössenböck went to Institut für Systemsoftware at Johannes-Keppler University in Linz (JKU) the development of V4 moved also. Therefore, V4 is sometimes also called Linz-Oberon in contrast to ETH-Oberon. The most recent version of V4 and extensions are available at JKU. Oberon V4 appears to be orphaned, there are almost no changes since 2000. Another repository of V4 is Claudio