Home OPOD
What's New
Rays & Shadows
Anti-crepuscular
Cloud shadows
Mountain Shadow
Earth's Shadow Blue Sky
Sunsets
Sunset Mirages
Green Flash
Green rim
I-Mir flash
M-Mir flash
Cloud-top flash
Observing
More Images
Moonrise/set
Opposition effect
Water Droplets
Rainbows
Ice Halos
High Atmosphere
Links & Resources
Search - Index
123456789012345678
| Observing & photographing green flashes |  |
 |
To see green flashes a sea horizon is best but the view from a tall building or a hillside can suffice. Flashes are also visible from aircraft. A low horizon is needed because pure I-Mir and M-Mir flashes take place below the astronomical horizon. The apparent sea horizon dips lower by an amount depending on your height above sea level. Flashes made by wavy inversion layers do not need such low horizons. Stand a few metres above sea level to see I-Mir flashes. M-Mir flashes require that you are above the inversion layer but the ideal height is a compromise because the higher you are above the layer, the shorter is any flash. In any event, inversion layers are often only a few feet above the surface. Don't be deterred by thin haze. It will dim the sun, thick haze will hide the sun completely, but a good flash might still be visible. Do not stare at the sun or look at it through any optical device - your eyesight could be permanently damaged. An I-Mir flash, the type most seen by eye rather than a camera, occurs just before the sun disappears altogether. Looking at the sun earlier will, as a minimum, bleach the red sensitive receptors of your retinas and impair your ability to see the flash faithfully. Don't take risks. |
|||||||||||||||||||||||
