The Society for Popular Astronomy
Ok everyone, we're now just a few days away from Friday evening's total lunar eclipse, caused by the Moon passing through Earth's shadow. By now I'm sure you're all checking your favourite weather apps two or three times a day to see what the forecast is for Friday night, and getting impatient for the Sun to set on Friday evening and for the fully eclipsed Moon to rise soon after. But if you want to be sure of seeing the eclipse you have some work to do before Friday...
Although this eclipse will be visible across the UK, unfortunately it is going to be quite challenging for us for a number of reasons. Firstly, no matter where you are in the country, the eclipse will have begun long before the Moon rises. The time of YOUR Moonrise will depend on where *you* are and what *your* local horizon is like. If you live in the north of the UK the Moon will rise later for you than it will for people living further south. (We know, we know, it's not fair, but there's nothing we can do about it!) Your local geography will affect your Moonrise time too: if you live somewhere quite high up, with a low, clear south-eastern horizon, the Moon will rise earlier for you than it will for people who live in places in a dip, or surrounded by mountains or hills. Common sense, we know, but it's easy to forget that when you read newspaper and magazine articles about the eclipse, or see posts on social media, and just see the same moonrise times being used again and again.
So, what should you do? If you're really wanting to watch the eclipse this coming Friday evening you need to make some plans, now. Most importantly of all you need to have a good observing site to go to to watch the eclipse. You'll want to be somewhere with as little light pollution and passing traffic as possible, and a really good, clear view to the south east. If you don't know of such a place already, over the next couple of days use Google Earth to research your area, or get out in your car and explore until you've found somewhere out of town that offers a great view. Then head there on Friday evening - you'll want to be there by absolutely no later than 8.30pm on the night by the way, just to get set up and to enjoy the whole experience.
So, what will happen, and when? The eclipse will begin long before we even catch sight of the Moon here in the UK. The Moon will begin to move into Earth's shadow at around 7.25pm, long before it rises for any part of the UK, no matter how far south it is. By 8.05 the Moon will be half-covered by Earth's shadow, but again it will still be out of sight for everyone in the UK. Totality begins at 8.34, when the Moon is fully covered by the Earth's shadow, but it will still not be visible from the UK - so frustrating!!! Down in London the Moon will rise at around 8.50, but observers further north will have to wait longer. In Cumbria Moontrise will be around 9.15pm, and in northern Scotland even later.
One important thing not being flagged-up very often in print or online is that we might not actually be able to see the eclipsed Moon rising. WHAT??? Well, with the sky still bright (the Sun will just have set, or still be in the process of setting, remember), you might struggle to see the Moon at first because the contrast between it and the sky will be very, very low. All you can do is keep looking for it - maybe using binoculars to scan the south eastern horizon if you have them? - and eventually the Moon will pop into view, glowing an orange-red colour. Lots of reporters and correspondents are waxing lyrical about how the eclipsed Moon will look "stunning" and "beautiful" as it rises, and once it has climbed up some ways from the horizon, and the sky has darkened, it should look really pretty, bloated and orange, almost like a huge hot air balloon hanging in the sky. But then again it might be a darker shade, more red than orange, and harder toi see, we just don't know. Every eclipse is different. Just don't be too surprised, or disappointed, if you don't spot the Moon until it is well clear of the horizon, and don't get to enjoy much of totality.
Once the Moon has shown itself, you might like to try taking photos of the total eclipse. You can try taking photos with just the camera on your phone, you might get something (you won't know if you don't try!) but really you need to be using a digital SLR or bridge camera and a zoom lens to make the Moon appear as big in the sky as possible. Ideally your camera will be on a tripod to keep it steady. Then it's just a matter of experimenting with ISO and exposure settings until you get something you like. Start with an exposure time of a couple of seconds and an ISO of 400 and see what you get. If the Moon is too dark or too light, just change those settings until you get something you're happy with. Then take as many as possible - and send us the best ones, we'd love to see them!
Going back to binoculars... you don't NEED a pair to watch the eclipse, because it will be clearly visible to the naked eye, but if you have or can borrow a pair for the evening they will definitely add to your viewing experience. With the Moon magnified through them the subtle pink, gold and blue shades and hues of the eclipse will be enhanced, and the Moon will look much more beautiful than it will to just the naked eye. But, again, don't worry if you can't get any.
When totality ends at around 10.15 the Moon will start to brighten from the left side. By then the Moon will still be quite low in the sky though, which is why it is so important to find somewhere with a low, flat south-eastern horizon to watch it from. By 10.45 the Moon will be only half eclipsed, but will still look very striking in the sky. It will all be over by 11.25, as the Moon emerges from the last traces of Earth's shadow and shines brilliantly in the sky once more.
And that's what will be happening on Friday night. One last thing - between 10.00pm and 10.15, look out for a bright red star shining to the lower right of the fully eclipsed Moon. This "star" will actually be the planet Mars, at its closest to us, and at its brightest in the sky, for 15 years! Once the total phase of the eclipse is over Mars won't just vanish, it will still be clearly visible, and will remnain a striking object in the night sky for many weeks after the eclipse.
We hope you get the chance to watch this eclipse. It's not scientifically important, or significant, but it is a lovely thing to watch in the sky.
Good luck - and don't forget to send us your photos or just your impressions of the eclipse! 🙂