ALERT: Strange dark streak seen on Mars on 22 October. More observations needed to confirm its nature.
On 22 October 2020, a dark streak was first reported to ALPO by Maximilian Teodorescu (Dumitrana, Romania). Maximilian has made a collection of images showing this streak for followup:
The length of this streak was measured to be over 600 km. Interestingly, on the Mars Orbiter Map, there are no features that can account for this dark streak.
This streak is also visible in my image taken at almost exactly the same day and time when the report was made public by Maximilian. The precise location of this dark streak is marked as shown above.
According to Max, the dark streak seems to have shifted its position and fades as it gets further away from the terminator. He is suggesting that it is the shadow of a very thin cloud. Imagers from the US are now seeing the same central meridian and are sending in their reports. Maximilian believes that it is a shadow of clouds in Tharsis, seen through the clouds themselves.
Further observations of this occurrence can be seen on the Mars' ALPO Japan page of 22nd October 2020.
My report is part of a fuller compendium made up by great planetary imagers including Maximilian Teodorescu, John Sussenbach, Christopher Go, Luigi Morrone, and Efrain Morales.
More observations are needed to confirm the nature of this feature.