The Noose of Mars in 2018

November 16, 2020

#01 (2)

Photographer: Paolo Bardelli 
Summary Author: Paolo Bardelli 

Mars has been front and center in the night sky in recent months. The Red Planet completes a revolution around the Sun in about 687 days, almost double that of the Sun, and on average every 26 months there’s an opposition -- Earth is in between Mars and the Sun.

From May through October 2018, I observed the path of Mars every evening, clouds permitting. The noose of Mars shown above was observed during the opposition of July 2018. Due to the reduced distance with Earth during opposition, the motion of Mars appears to reverse and becomes retrograde, causing the loop in its orbital motion.

Several hundred years ago, when there was still a geocentric view of the cosmos, the strange retrograde movement forced astronomers to introduce epicycles and deferents to try to justify these odd movements. By placing the Sun at the center of the Solar System, these problems were easily solved. Photos taken on July 27, 2018.

Photo Details: Canon 60Da camera; 50mm lens; on star tracker. Processing: Iris; Photoshop CC; Startrails.