Did you know that the Blood Moon (total lunar eclipse) on January 31st is going to be special because it is happening during a Blue Moon, or the second full moon of the month (depending on definition)? The last one was in 1866 and the next one will be in 2028.
On 31 January, we will see a total eclipse of the Moon which will be visible right across Australia and NZ, Asia and the Pacific – in fact anywhere in the world where it is night at the time. What happens is that during a lunar eclipse te he full Moon passes completely through the shadow of the Earth. This is called the Umbra. The whole eclipse process will take around 5 hours and 10 minutes.
The total phase will last about 1 hour and 17 minutes.
So, what does this mean?
The Moon will change gradually from its usual white pearl colour to reddish, hence the term blood moon, then back to its original colour. The shade of red varies between eclipses and is affected by external factors such as the Earth’s atmosphere, the presence of dust from bushfires, volcanic ash or dust or similar. This dust in the Earth’s atmosphere blocks out more refraction of the Sun’s light leading to deeper darker red effects.
This eclipse will occur at the same time as perigee Moon that means that the Moon is the closest to Earth it gets during its orbit. The perigee Moon will occur the day before and so this full Moon is also designated a Super moon.
During the hour or so of totality, there will be many more stars visible than what you normally see during the full Moon including parts of the Southern Milky Way. It’s a great chance to take a short against the background stars.
Observing the Lunar Eclipse
You will not need any special equipment to observe a lunar eclipse. Just head outside with a comfy chair, insect repellent and cool drink and watch it happen. It is safe to look at – no need for a telescope or binoculars – but if you have them check it out!
The timing for the event is as follows: (for AEDT)
These timings are from timeanddate.com:
9:51 pm – Penumbral Eclipse begins
The Earth’s penumbra starts to cover the Moon’s face.
10:48 pm – Partial Eclipse begins
Partial moon eclipse starts – the moon is starting to redden.
11:51 pm – Total Eclipse begins
Total moon eclipse starts – completely red moon.
12:29 am – Maximum Eclipse
Moon is closest to the centre of the shadow.
1:07 am – Total Eclipse ends
Total moon eclipse ends.
2:11 am – Partial Eclipse ends
Partial moon eclipse ends.
3:08 am – Penumbral Eclipse ends
The Earth’s penumbra ends.
So, why do we not have one every full Moon?
Pictures of the Moon’s phases often make it look like there should be a lunar eclipse during each full Moon and a solar eclipse during each new Moon.
However, there are two things that need to happen for a full lunar eclipse.
First, the Moon has to be full, so there is only an opportunity for a lunar eclipse about once each month.
Second, the Moon has to pass through Earth’s shadow.
The Moon’s orbit around Earth is tilted a little by about 5 degrees to the Earth’s orbit around the Sun. This means that most of the time the Moon is slightly above or below Earth’s plane of orbit — and out of the shadow cast by Earth where it blocks the Sun’s light.
No eclipse occurs during these full Moons.
But two to four times each year, a full Moon occurs when the Moon’s orbit intersects Earth’s plane of orbit, placing the Moon in Earth’s shadow — and a lunar eclipse occurs!
How many Februaries do not have full Moons?
So since there are two full Moons in January – there will be none in February, the next one will not be until March 1. The last time February missed out on a full Moon was in 1999. . Over the course of a thousand years, from 2000 to 2999 there are going to be 48 Februaries without a full moon, and even three leap year Februaries (29 days) without one.
What is a Blue Moon?
The term has been used in more recent times to designate the second of two full moons in a calendar month. The older definition has a Blue Moon defined as the third of four full moons occurring in a single season. This blue moon is the first of two this year – the next is in March since it has 31 days.
There is an average time of about 29.5 days between two full moons. The average length of a month is approximately 30.5 days making it unlikely for any given month to have two Full moons. It does happen, however and there will be 41 months in any given 100 years with two full Moons. So, in that context, a blue Moon will occur once very 2.5 years.
A truly blue coloured Moon is rare. The moon can really appear to be blue and can occur following volcanic eruptions or major widespread bushfires. These two events cause an increase in atmospheric ash and dust particles. If these particles are the right size, which is about 1 micron or one-millionth of a metre, they act as a colour filter, which gives the Moon a blue tint
animation from: Tomruen – Wikipedia