Change in Venus Express's local time at ascending node
This plot shows the change in Venus Express's local time (Y-axis) in the spacecraft's ascending arc for the reporting period MTP076, 5 February to 3 March 2012. The X-axis shows the orbit number; each orbit lasts 24 hours. Local time at ascending node (LTAN) at terminator orbits is 06:00 and 18:00; LTAN of 12:00 is noon and LTAN of 24:00 is midnight.
As on Earth, standard time zones are defined by geometrically subdividing Venus' spheroid into 24 wedge-shaped sections bordered by meridians separated by 15° longitude each. The local time in neighbouring zones differs by one Venus hour, or 1/24th of a Venus day. The variation in the position of the Sun from one end of the zone to the other (east vs. west) covers 1/24th of the sky.