Saturday, April 19, 2008

Pitcairn Island's Solar Eclipse Stamp Sheet

A solar eclipse occurs when the moon passes between the earth and the sun, obscuring at least part of the sun. There are several different kinds of solar eclipses.

Depending on your location and the distance of the moon from the earth, you might be lucky to see a total eclipse, in which the entire face of the sun is hidden by the moon. These occur every 18 months or so, but are only visible from a very narrow viewing window on earth.

A partial solar eclipse occurs when the sun, moon and earth are not exactly lined up, but the moon nonetheless obscures at least a part, but not all, of the sun.

Annular eclipses are a variation of the total solar eclipse in which the moon does not appear large enough to cover all of the sun. The moon, which travels in an elliptical path around the earth, is sometimes farther away from the earth, which will make it look slightly smaller when viewed from earth. In an annular eclipse, the smaller appearing moon cannot completely hide the sun, so when it the moon is exactly centered over the sun, a "ring" (or annulus) of sunlight appears around the moon. These are slightly more common than total eclipses.

The rarest type of eclipse is the hybrid solar eclipse, in which a solar eclipse appears as both total and annular. The cause of this phenomenon is the curvature of the earth ... as the eclipse "travels" across the face of earth, the curvature of the earth alters the apparent distance from the earth to the moon, making the moon appear to change size very slightly. When the moon appears its largest, i.e., when it is closest to earth's surface, it will completely block out the sun's light, yielding a total eclipse. As the eclipse moves across the surface of the earth, the curvature of the earth makes the moon farther away from the surface, resulting in the moon appearing slightly smaller. The "smaller" moon hides slightly less of the face of the sun, causing more of the sun to be visible, resulting in an annular eclipse. This type of solar eclipse is the rarest of the rare ... only about 5% of all solar eclipses are hybrid.

On April 8, 2005, a hybrid eclipse occurred that was visible throughout the southern Pacific Ocean, as well as parts of South and North America. Most locations saw a partial solar exclipse, since from the viewing angle, only a small portion of the sun was covered. The island of Oeno in the Pitcairn Islands, however, was very close to the center of the moon's shadow, also known as the path of totality.

To celebrate this rare event, Pitcairn Islands produced a 3-stamp issue featuring graphic depictions of what the eclipse might look like. The stamps had a First Day of Issue for the date of the eclipse, so the depictions are artist renderings based on photographs of prior eclipses.

The souvenir sheet consists of 3 circular stamps denominated $1, $2 and $3 (NZ).

The stamps went on sale April 8, 2005 and ceased to be offered 2 years later. You should be able to find these stamps with a little bit of searching through the internet or on stamp auction sites.

1 comment:

sweetiepie said...

I love to read and always see more about Pitcairn, so thanks for sharing this.