It appears that numerous imagers captured the features I discovered yesterday and brought to the attention of the amateur community. It’s good to know that I’m not just seeing things!
Here are a few more images to help ponder the question of whether it’s a high-altitude water-ice cloud of some sort or perhaps a dust plume. I think it looks like a mushroom cloud from an impact, but that’s just what I’m seeing. We’ll learn more as those with more experience with Martian clouds chime-in.
Here is one of the best green-light images of the feature. I a have a lot of data to sort through and will update.
and another RGB image from 24 hours later with an inset showing the feature enlarge and enhanced.
I’ll keep updating here, rather than individual posts, for the benefit of those collecting the data for scientific study. This is quite an exciting event and now that data is being provided by accomplished amateurs and experts from all over, we’re realizing what an unique and interesting phenomena we’re seeing!
Here’s one from the 19th (the day before) showing the “spot” as a dot (famed Mercury imager John Boudreau calls it a “nipple”) in the southern hemisphere.