Observe a partial eclipse of the Sun  

The partial phase of the total eclipse of the Sun of 21 August 2017, the so-called ‘Great American Eclipse’. Image: Jamie Cooper.

This month’s partial eclipse of the Sun is visible across the length and breadth of the UK on the morning of 25th October 2022. Solar eclipses visible from the UK are pretty infrequent, so this event presents a fine opportunity to watch as the Moon gradually encroach upon the Sun.

The partial eclipse begins soon after 10am BST, when the Moon contacts the Sun’s northern limb. Observers in Scotland are marginally first in line, at 10.03am BST, and they’ll see 30.6% of the Sun’s diameter hidden, the largest (see the table below). 

At NO POINT in this eclipse should you look at the Sun directly, as you can during totality of a total eclipse of the Sun when the whole of the Sun is covered by the Moon. The best way to view is by ‘projection’, when a pair of binoculars or a small telescope can be used to project the solar disc onto white card; you must cap the instrument’s main optics, as well as any finder while you’re lining up the Sun (see the image).

Projecting the Sun’s disc through a small telescope onto a sheet of white card is a safe method of viewing the partial eclipse. Image: Steve Ringwood.

The eclipse is visible across almost all of Europe, where more easterly cities, such as Berlin and Warsaw will experience a larger partial eclipse (magnitude 43.6% and 52.1%, respectively). Chelyabinsk, in Russia’s Ural Federal District, has the accolade of the largest eclipse for a major city; at 2.02pm local time, 83.4% of the solar disc will be hidden by the Moon (the maximum eclipse occurs at 11.01 UT, with a magnitude of 86.19%, or 0.8619). 

The ‘magnitude of the eclipse’ is the fraction of the diameter of the Sun’s disc that is covered by the Moon (it can be expressed as either a percentage or a decimal fraction [i.e. 30.6% or 0.306]. Eclipse obscuration is the fraction of the Sun’s area occulted by the Moon.

On the morning of 25 October there’s a great opportunity to see a partial eclipse of the Sun. At maximum eclipse, 30.6% and 25.9% of the Sun’s diameter is hidden by the Moon from Edinburgh and London at 10.55am and 10.59am BST, respectively. All AN graphic by Greg Smye-Rumsby.