What is so super about today’s supermoon? This full moon will occur that appears slightly larger and brighter than usual. It’s caulked the Harvest Moon.
The reason is that the Moon’s fully illuminated phase occurs within a short time from perigee – when the Moon is its closest to the Earth in its elliptical orbit.
Pictured above, a supermoon from 2012 is compared to a micromoon — when a full Moon occurs near the furthest part of the Moon’s orbit — so that it appears smaller and dimmer than usual. Given many definitions, at least one supermoon occurs each year, with the next being 2015 August 30.
Around the time of Harvest Moon, the full moon’s path is tilted at a shallow angle to the eastern horizon making with successive moonrises only about a half hour apart instead of the usual 50 minutes. Source: Stellarium
Although the precise conditions that define a supermoon vary, given one definition, tomorrow’s will be the third supermoon of the year — and the third consecutive month that a supermoon occurs. One reason supermoons are popular is because they are so easy to see — just go outside and sunset and watch an impressive full moon rise! Since perigee actually occurs today, tonight’s sunset moonrise should also be impressive.
How we perceive the moon’s size may have much to do with what’s around it. In this illustration, most of us seen the bottom moon as smaller, but they’re both exactly the same size. Crazy, isn’t it? Credit: NASA
A series of photos of the full moon setting over Earth’s limb taken by from space by NASA astronaut Don Pettit on April 16, 2003. Refraction causes a celestial object’s light to be bent upwards, so it appears higher than it actually is. The bottom half of the moon, closer to the horizon, is refracted strongest and “pushed” upward into the top half, making it look squished. Credit: NASA
Can you see craters with your naked eye? Yes! Try tonight through Wednesday night. Plato is the trickiest. Credit: Bob King
source APOD, universetoday