Observing Projects
Atmospheric Optical Phenomenon
Atmospheric Optical Phenomenon cover a wide range of interesting sights that can be seen in the sky on many days throughout the year. Since becoming interested in astronomy I have also learnt more about these strange and usually beautiful sights and have tried to capture them on camera when possible. This page shows the highlights of the photos, more of which can be seen in my gallery on Flickr. These photos were taken by myself between 2006 and 2007 with a Pentax Optio 33lf and a Panasonic DMC-FZ7.
You might also be interested in Martin Mckenna's Atmospherics Gallery.
Rainbows
The classic and most widely recognised optical phenomenon, rainbows require sunshine and rain and appear opposite to the sun in the sky. They are caused by sunlight being reflected back from spherical drops of rain, causing a bright spectrum to be seen.
Resources: Wikipedia · AtOptics
Sun Dogs
A sun dog (or parhelion) is one of the most common types of halo associated with the refraction of sunlight by small hexagonal prism shaped ice crystals. They usually appear close to sunrise or sunset when faint cirrus or cirrostratus clouds have built up and are located on the circle of the 22° halo but move out as the sun rises.
Resources: Wikipedia · AtOptics
Crepuscular Rays
These are rays that appear to radiate from a single point in the sky and are caused by sunlight streaming through gaps in clouds. They are usually most visible around sunrise or sunset and are so pronounced because of the effects of scattering and diffraction.
Resources: Wikipedia · AtOptics
Anticrepuscular Rays
These are similar to crepuscular rays, but are seen opposite the sun in the sky as the straight line rays converge on the anti-solar point. They are usually dimmer than crepuscular rays.
Resources: Wikipedia · AtOptics
Solar Halos
One of the most common types of phenomenon, these halos are visible anytime there is hazy, thin cirrus clouds in the sky whcih are formed from tiny, uniform ice crystals.
Resources: AtOptics
Solar Pillars
These appear when the sun is close to the horizon and are the result of light glinting off millions of ice crystals to form a narrow, seeimgly vertical pillar extending from the sun by 5-10º.
Resources: AtOptics
Iridescent Clouds
These are thin clouds which are formed from very similar sized droplets such that diffraction of sunlight through them makes them shine with colours like a corona. They are usually found close to the sun (hide it behind a building) and appear most often in newly forming altocumulus, cirrocumulus and lenticular clouds.
