Ghosts!

OPOD gets 'multiple sun' images almost weekly. A plane glass filter or taking the photograph through a window is usually responsible.

A strange phenomena might be real if it is seen by the unaided eye (not camera viewfinder) and is the same on at least 2-3 images of a hand-held camera. Hand holding varies the viewing direction enough to show up lens or filter reflection effects.
 
Metals & Mirrors

Metals are good reflectors of light and good conductors of heat and electricity. Other materials, sulphur, moon rock, cheese, are not.

The key difference is the extent to which electrons in the material are delocalised from individual atomic nuclei. In non-metals, electrons are tightly bound to individual atoms with only one or two outer ones shared between near neighbours. In metals, many electrons are not localised around any one atomic nucleus but wander or are spread (depending on one’s quantum mechanical viewpoint) throughout the metal. Electricity and heat conduction via electron motion is consequently easy. A degree of delocalisation can occur in non-metals – graphite with extensive pi orbital overlap is a reasonable conductor and has a metallic sheen.

The good metallic electron mobility has consequences when a charge approaches the surface. Electrons (or electron density) migrate to balance the charge. Thus an approaching positive charge attracts electrons to the metal surface. A negative charge repels electrons leaving a region positively charged by the less well shielded metal atom nuclei. The overall result is that electric fields are compensated. Fields do not penetrate metals or do so only very weakly.

Incident light waves represent a time varying electric charge or field. Counter currents are induced within the metal surface. The light wave cannot enter and the counter currents produce an outgoing wave – a reflection.

All very well, but electrons are not perfectly responsive. As the incident light wavelength shortens and its frequency increases the electrons are forced to oscillate faster. Eventually they start to lag behind the wave and the reflectivity begins to decrease. Metals are poorer reflectors of UV and shorter wavelengths. In gold and copper the lag shows up even with visible light. Gold reflects blue poorly and so appears yellow. Copper does even less well with blues and greens falling in reflectivity giving its beautiful red hues.


This explanation is overly simplistic but it has some truth!

Rainbows, Ghosts, Towers

Ian Anderson sent this image from a time lapse camera monitoring the construction of a power line north of Perth, Western Australia. There is a lot happening. Primary and secondary rainbows are separated by the dark sky of Alexanders Dark Band. Nearby rain extends the primary below the horizon. The largest tower has its ghost just to its left. The zinc coatings of the new metal towers blaze as the brightest objects in the landscape as they reflects the sun's rays with high efficiency.

Atmospheric
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Rainbows & raindrops

The primary bow is formed by rays reflected once inside raindrops. Many rays contribute, some of which form the brighter sky inside the bow. The main colour forming rays enter through a ring shaped zone on each raindrop.

Secondary bow rays (two internal reflections) skim closer to the drop's edge. Their entrance zone is another and slightly larger ring.

The more glancing angle of impact of the secondary forming rays results in a greater angular separation of colours during the entrance and exit refractions. The secondary is almost twice as wide as the primary.