About 25% of the sun will be blocked on Tuesday when the moon passes between it and Earth.
Sky watchers across the UK will be able to see the phenomenon, with those in northern Scotland expected to enjoy good views.
Dr Robert Massey, of the Royal Astronomical Society, said the eclipse would cause the moon to block the view of “some or all of the bright solar surface” and the sun would “appear to have a bite taken out of it”.
Observers in western Siberia, Russia, will get the best view of the eclipse, where the moon will obscure a maximum of 85 percent of the sun, Massey added.
In London, the eclipse will begin at 10:08 a.m. on October 25, and peak at 10:59 a.m., when the moon will eclipse about 15% of the sun.
Lerwick in Shetland is expected to have a better view, with 28% of the sun obscured mid-eclipse.
Jake Foster, astronomer at the Royal Observatory in Greenwich, said: “The eclipse will be visible across the UK, as well as large parts of Europe and central and southern Asia. The amount of dimming you see will depend on where be on Earth.”
He added: “Although some of the sunlight will be blocked, it will not get noticeably darker in the UK during the eclipse.”
The partial eclipse will end at 11.51am in London.
Massey said looking directly at the sun can cause serious eye damage, even when a large portion of the sun is blocked. It is also not wise to look at the sun with binoculars, telescopes, or a telephoto lens on an SLR camera.
He added: “The easiest way to see an eclipse is to use a hole in a piece of cardboard. You can then project an image of the sun onto another piece of cardboard behind it (experiment with the distance between the two, but it should be like at least 30 cm).
“Under no circumstances should you look through the hole.”
Massey said another popular method used to view an eclipse is the mirror projection method. He said: “You need a small, flat mirror and a means of placing it in the sun so that it reflects the sunlight into a room where you can see it on a wall or some kind of flat screen.
“You can also have eclipse glasses with a certified safety mark, and these are available from specialist astronomy suppliers. As long as they are not damaged in any way, you can see the sun through them.”
Binoculars or telescopes can also be used to project the image of the sun. Massey said: “Mount them on a tripod and place a cardboard with a hole over the eyepiece, and place another 50cm to a meter behind.
“Point your telescope or binoculars at the sun and you should see its bright image on the separate card.”
For those wishing to follow the event, the Royal Observatory Greenwich will stream the eclipse live on its website and YouTube channel.