An interest in observational astronomy also leads, at least in my case, to an interest in the science of how the telescope reflects and refracts the light coming from distant regions of space with its mirrors and lenses to form the image that I see through the eyepiece. Then there's also the brain's role in interpreting the image that the eye sends to it. Here are a couple of more down to Earth effects that I witnessed (or created with the last image) that are also examples of optical phenomena.
First is this that I noticed on the wall of my bedroom one morning. I couldn't tell exactly what it was at first until I imagined the image flipped upside down.
Seeing it this way makes it more obvious. It's an extended cab pickup truck that was parked across the street, and its image was formed on my bedroom wall because of a very tiny gap in the dark drapes that cover the window. The gap was acting like a pinhole camera and projecting the image across the room and onto the wall. Since the pickup was white and sitting in full sunlight, it's the brightest and therefore most obvious thing in the image.
Here's something else that gets your brain involved. An ordinary camera can take 3D images with a simple trick. First, take a photo. Then, depending on how far away your subject is, take a step a few inches (for close-up subjects) or a couple of feet (for distant subjects) to the left and take another photo, identical to the first except for the slightly different point of view. Put both pictures side by side in front of you so that you can converge your eyes (in other words, going slightly cross-eyed) so that the two pictures merge into one. If you can get away with this without getting a headache, your brain will interpret the image in 3D. Click on the image above to enlarge it for an easier view. This photo is at Prague Castle in the city of Prague, Czech Republic. I've taken a few pictures like this at various places, and the results are usually quite striking.