Several years ago I came across a several of these images in a magazine article. The originals were among 169 paintings bound together in what became known as Augsburg Book of Miraculous Signs, produced and bound around 1550. The article reported that the book had just sold at auction to a private collector. I despaired that because it had ended up in a private collection and not a museum, the rest of these truly marvelous images might never be seen.
Stumbling around the web, as I am wont to do I discovered that TASCHEN books has published a facsimile edition that is absolutely gorgeous. One of the miracles of this Book of Miracles is that it survived, having been re-bound in the 19th century. So often books like this are dismantled and the contents dispersed piecemeal.
The book includes depictions of al sorts of miracles and mysteries, but these cosmological phenomena, thought to be depictions of comets, are particularly intriguing to me.