The Night Sky #Shorts
The Mars-Pleiades Conjunction
This is a short post in my series on our night sky.
You can find all episodes in this series here
On Wednesday, March 3rd, 2021, the planet Mars appeared very close in the night sky to the Pleiades, a rather well-known star cluster. Find out more about the Pleiades in episode 4.
While Mars and Pleiades are separated by hundreds of light-years in reality, from our point of view here on Earth, during the few days before and after that particular Wednesday, they appear very close to each other. This phenomenon is known as a conjunction.
The conjunction of Mars and Pleiades captured on March 4th, 2021. Image created using a Canon 6DMarkII camera at a focal length of 300mm, f/7.1, ISO 3200. A total of 44 images each of 180 seconds (for a total of 132 minutes of integration time) were captured.
A Mars-Pleiades conjunction that is this close will not happen again till 2038. The previous one was in 1991.
The bright orangeish object at the bottom-left of the frame is Mars and the bluish cluster of stars towards the top-right is the Pleiades. The cloud-like structures around the stars in the Pleiades are actually a reflection nebula that is reflecting light from the many blue giant stars in the star cluster.
This picture clearly shows the differential speeds of Mars and the stars. Mars, as a planet in our Solar System, moves much faster across the sky from our point of view as compared to the stars which are much further away. This image is an integration of 2 hrs 12 mins of exposure time. Over these 2+ hours, Mars has moved a larger distance in the sky compared to the stars, and this is evident as Mars not being circular (like the stars) but a streak.
View episode 4 in this series here for more information on the Pleiades.