A supermoon total lunar eclipse, or “super blood moon”, will occur in the early hours of Monday morning – an extremely rare and special event that will be viewable (depending on cloud cover) from the UK.
Only five total lunar eclipses have coincided with a supermoon since 1900. The last time it occurred was in 1982 and the next time it will happen is in 2033.
The moon will turn red as it passes through the shadow of the Earth – some sunlight still illuminates the moon hence the “blood moon” nickname – at 3.47am BST on 28 September.
What is a supermoon?
Some years ago, astrologer Richard Nolle coined the term “supermoon” to denote when a full or new moon occurs when it is particularly close to Earth.
There are typically six supermoons every year. However, this particular full moon and total lunar eclipse are occurring at a slightly more special time of the year than a “normal” supermoon. It is occurring during 2015's perigee full moon - the absolute closest full moon we'll see this year.
At this distance from us, the moon will appear around 14 per cent larger than usual.
Completing the tetrad
The 27 September eclipse also marks the completion of a lunar tetrad - four consecutive total lunar eclipses occurring at approximately six month intervals.
Although some periods have gone by with no tetrads at all, when they do occur there can be up to eight in a century. The 20th century saw 5 tetrads, and the tetrad of 2014-2015 is the second of eight total between 2001 and 2100.
The first three eclipses of this tetrad took place on 15 April and 8 October of 2014, and 4 April of 2015.
Where to see it
With high pressure with us on Sunday night, you could be forgiven for thinking that would make an easy job of forecasting the weather for the lunar eclipse. If only that were true!
High pressure will bring some clear skies but at this time of year it also brings localised dense fog patches. Fog may well form in the Vale of York and favoured inland areas.
Meanwhile, a weak weather front to the northwest looks like obscuring the view for western Scotland and Northern Ireland.
So where will skies be clearer? At this stage it looks as though Eastern Scotland, North East England, the Midlands, Wales and South West England should be the favoured spots.
However light easterly winds could allow some eastern coastal areas to see some cloud overnight too.
As forecasters chase the cloud under the high keep up to date with us for the latest weather forecast and viewing prospects.