I can't resist photos of condensation trails in the early morning when the lighting enhances the 3-d perception, and fools the eye. Here, the lower in the sky, the farther away the trail must be, yet the illusion is such that they look like fangs piercing the clouds. The crepuscular shadows add to the image.
Any type of sky watching begins with the atmosphere which often offers something interesting or beautiful.
3 days ago