Not sure what a perigree full moon is? This phenomena is more commonly known as a “supermoon” and the one coming upon Sunday, August 10, will be the most impressive of the year coming a mere 221,765 miles from earth which is about 30,000 miles closer than is typical due to the parabolic arc of its orbit.
What impact does the occurrence of a supermoon have here on earth? Visually the moon appears up to 30% brighter and 14% larger than at any other time, because it is a full moon at the closest approach to earth. While this is by no means something new, the advent of high powered digital cameras and the increase in social media have seen a huge increase in people sharing the images they have captured of the moon, particularly with globally recognizable landmarks like the Christ the Redeemer statue in Rio De Janiero, the Eiffel Tower and even the casinos of Las Vegas. In some respects the visual image seen with a perigree full moon above the horizon is an optical illusion. The term “moon illusion” is used to explain the unnaturally large appearance of the moon when it is near the horizon when it beams though foreground objects such as trees or buildings. The theory is that moon illusion occurs because, when the moon is on the horizon, the objects give a degree of scale to the moon, whereas when the moon is directly overhead, without man-made objects to compare, depth perception is hindered. If you are attempting to capture the moonrise, it will be emerging from North American horizons around 8:30 PM – 9:30 PM (with variations for geography).
Unlike a solar eclipse, there is no risk to your eyesight while observing it. As in most nocturnal astral events, finding a spot higher in elevation and away from artificial light will yield the best results. If you wish to photograph the super moon, the use of a tripod and time release, will stabilize and reduce movement when using the longer shutter speeds that produce the most vivid results. On Sunday evening your views will be the best, but you can still witness the effects on Saturday evening, which will provide a nice opportunity for photographers to check their location and settings prior to the big event on Sunday night.
With all the talk of the supermoon, you might not be aware that it is a relatively common occurrence, happening on average about once a year. A full moon cycle is about 412 days and halfway through the cycle the moons immediately preceding and following can be super moons, which is why in 20014 we are having them on July 12th, August 10th and September 9th, with the August one being the closest.