Atmospheric
Optics
Many Moons
~ Or through a glass deceptively. One of Robin Andrea's windows effectively has four panes of glass when a slider panel is moved over the middle section. Robin deliberately photographed the moon through all four panes to show how multiple images form.
Images like these are frequently mistaken for mirages or even stranger objects.
When unusual effects apparently in the sky appear in photographs, always take at least two more images with a hand held camera. If the effect(s) remain identically placed AND are seen the same with the unaided eye then they 'might' be real.
Image ©Robin Andrea, shown with permission
Refraction across uneven glass produces multiple images. In effect, the object is seen through prisms of different tilt and wedge angle.
Add internal reflections and the images multiply further!
The diagrams exaggerate the tilt and unevenness.
Dancing moons.
Three hand held camera images by Robin Andrea show that they are not in the sky.
Mirages - Other Effects?
Strange sightings not fitting our preconceptions should not be lightly dismissed. But to be worth serious analysis they demand exceptional care and thoroughness in recording and documentation. Take several hand held still camera shots that preferably include landmarks, check what the unaided eye sees! Keep the original camera files and their EXIF data. Separately document time, place and sky conditions.
Two glass panes might be slightly tilted. A series of ghost images result, displaced 2, 4, 6... times the tilt angle. They get weaker and weaker and so only bright objects give visible extra images. The power lines in the top picture are not ghosted.
The tilt need not be uniform, it might vary from place to place across the window.
Unless the tilt is very uniform indeed, moving your head or camera will soon reveal the illusion.
Slightly tilted filters or plane elements in a lens can give the same effects in a camera.
