A Faint Glow: Gegenshein

From the photographer: “In the antisolar point and therefore at 180 ° from the Sun, in the dark nights in late autumn, around midnight it is possible to observe an increasingly rare phenomenon: the Gegenshein or Counterglow. It is a faint glow, in full dark sky, given by the sunlight backscattered by interplanetary dust. Unfortunately, a necessary condition for observation is to find an extremely dark place.

It is really difficult nowadays and if we continue to illuminate our nights without paying attention to waste and more sustainable types of lighting, this phenomenon will no longer be observable, it will be canceled. To capture it, in the northern hemisphere, I waited for the best moment, that is when the antisolar point would have distanced itself from the glare of the Milky Way and would have risen into the sky on a dark and moonless night.

I live in Sicily and October 31, I headed towards a very dark area in the Nebrodi mountains. I brought an SQM meter with me to check, if I was able to observe the phenomenon with the naked eye, how much darkness can be useful for observation. I waited for the first quarter of the moon to set (at 10:20 pm), the measurement at 10:45 pm gave an SQM of 21.19, I looked up and I identify the glare of the Milky Way.

I then moved my gaze over the constellation of Taurus and I perceived a very slight glow whose identification improved if I did not observe it directly. I felt a great amazement in recognizing that glow, many times I look at the sky and recognize constellations, planets … that evening there was something more to observe and photograph. I then took 2-minute astro-chased shots and then processed the image without forcing anything. I wanted to leave the faint glow as I remember observing it. Other objects in this sky are visible thanks to the Sun that at that moment was shining at my feet on the other side of the world: we observe Jupiter, which has recently been right at the antisolar point and therefore in opposition and then we see Mars.”

Technical details: Nikon D750, fisheye 8mm; 800 ISO; f/3.5; 120 sec. + Startrak