Normally I use this space to make some "witty" comments to ease you, our readers, into each article. But today I'm going to get out of the way because I just can't say it better than seasoned MSc student Charissa Campbell and her animations: "Here are the beautiful movies taken on sol 1758. On the left is the SHM which shows the Martian landscape with the wispy clouds above. The right is the ZM that is taken directly above the rover but still shows the similar wispy features as the SHM. They are both taken around 7:00 am."
by Charissa Campbell
One of my roles on the Curiosity Science Team is to process the atmospheric movies taken by the rover. They consist of 8 sequential images of the sky above the rover. There are two kinds: Zenith Movie (ZM) and Supra-Horizon Movie (SHM). The only difference between these two observations is the angle of the camera with respect to the rover. The SHM is taken at an angle of 38.5° elevation, which is right above the crater rim, while the ZM is taken directly above the rover at an angle of 85°.
Most of these movies are taken either in the early morning or afternoon as studies show that these two periods during the sol are when clouds most likely appear. In fact, there even is a season on Mars that exhibits more clouds than other times of the year. This is known as the Aphelion Cloud Belt (ACB) and starts in the late fall in the southern hemisphere, where Gale Crater is located. It is given this name because it peaks around the Aphelion of Mars; the furthest point that Mars will be in its orbit around the Sun. Clouds can be seen at other times of the Martian year. However, the ACB is a season that distinctively shows clouds. We even use this recurring season to plan atmospheric movies for Curiosity so that we can analyze these clouds in greater detail.