KUALA LUMPUR: The largest supermoon this year is expected to illuminate the skies tonight and peak after midnight at 2.37am on Thursday.
A supermoon occurs when the moon is at its closest position to Earth (perigree) while appearing as a full moon at the same time.
National Planetarium senior principal assistant director Mohd Zamri Shah Mansor said the moon would be at its closest ever distance to Earth at 5.05pm today.
He said people from all parts of the country could also observe the supermoon on early Thursday morning, depending on the weather conditions at their respective locations.
“Every month, the moon will pass through two distinct points within its orbit, namely the nearest point to the Earth called perigee and the furthest point from Earth called apogee.
“A supermoon is a full moon that occurs when the moon is exactly at the perigee or within 90 per cent of the distance to perigee.
“The closer the full moon is to Earth, the bigger and brighter it appears when observed from Earth.
“Since July’s full moon distance is the closest among other supermoons in 2022, it will appear as the largest supermoon for this year,” he told the New Straits Times.
Although the moon enters its perigee at 5.05pm today, Zamri said the moon would only reach its full moon phase and peak at 2.37am on Thursday.
At this point, the distance between the moon and Earth will be 357,418 km.
Zamri said the supermoon was best observed while it is rising in the east or when it is nearer to the horizon while setting in the west.
The supermoon, he said, would appear larger and brighter while rising or setting, compared to when it is high up in the sky due to the effects of “moon illusion.”
“Even though it will peak at 2.37am on July 14, the supermoon could be seen when the moon rises at 6.06pm in Semporna and 7.16pm in Kuala Lumpur today, until it sets after reaching its peak at 2:37am on Thursday.
“The moon will be rising in the east direction around 6.06pm in Semporna, Sabah and around 7.16pm in Kuala Lumpur tonight.
“It will peak at 2.37am on Thursday when the moon moves slightly towards the west direction,” he said.
Zamri said tides would be higher during this period due to the combined effects of gravitational pull by the moon and the Sun towards the ocean water.
These are called spring tides, he added.
“During supermoons, the tides could go up to five centimetres higher and this phenomenon is called perigean spring tides,” he said.