Tonight, Vietnam welcomes a super blue moon, which may be... orange.

(NLDO) - The super blue moon appearing on the night of August 19 and early morning of August 20 will be the beginning of a series of 4 consecutive super moons.

According to Date and Time, as of the morning of August 19 and from the observation angle from Ho Chi Minh City, the supermoon has reached a roundness of over 99% and is ready to appear in its most beautiful state on the evening of the same day.

Live Science reports that August's supermoon will be the first supermoon of the year and is called a super blue moon because it is the third of four full moons in the same astronomical season.

The supermoon on the night of August 18 with a roundness of approximately 98% from the angle taken from Go Vap district, Ho Chi Minh City, with two impact craters Copernicus and Tycho standing out prominently - Photo: Anh Thu

There is also another type of super blue moon called a monthly super blue moon - the second full moon in the same month.

According to NASA, both types of blue moons typically only occur once every 2-3 years.

The most recent seasonal blue moons were in October 2020 and August 2021; the next seasonal blue moon will occur in May 2027.

Although it's called a "super blue moon," you'll see the August full moon has a slightly orange color, with varying shades depending on the viewing area.

A summer supermoon with a rather deep orange color, as seen from the US - Photo: NASA

There are two phenomena that contribute to this strange orange color.

First, the summer moon usually hangs low, so the May, June, July, August, and possibly September moons rise above the horizon and force us to view them through a thicker layer of atmosphere than when they are higher.

This layer of atmosphere also acts as a prism, scattering light, making the moon appear a little redder than usual.

If you look at the moon at sunset in other months, you will also see it has a pinkish-orange color, while the moon at high altitude often has a clear silver glow.

The second reason is that if the air you are looking through is polluted with smoke and especially smoke from summer forest fires, this orange color will be even darker.

According to Time and Date, the time of the absolute full moon in Vietnam time will be 1:25 a.m. on August 20.

However, if you want to see the biggest and orangest supermoon possible, you should take advantage of sunset on August 19.

That's when the "moon illusion" phenomenon occurs because the viewing angle makes the moon appear its deepest orange color of the evening and also makes it appear larger than usual, due to a type of optical illusion.

If you miss it, you still have the chance to see other supermoons in September, October and November. Of which, the full moon in October will be the closest to Earth, so it will also be the biggest supermoon.

Source: https://nld.com.vn/dem-nay-viet-nam-don-sieu-trang-xanh-co-the-mau-cam-196240819085125204.htm