On the evening of 19 October, a 91%-lit waning gibbous Moon will pass immediately south of the main part of the famous blue star cluster known as the Pleiades.
The beautiful Pleiades open cluster, M45, in Taurus, is easily visible with the naked eye and is spectacular even through a modest pair of binoculars, making it one of the most visually impressive targets to show beginners.
The 19 October encounter between the Moon and the Pleiades is two days after the full Moon, which is being called a 'supermoon' by some due to its close proximity to Earth.
The Moon's Pleiades passage
The Moon’s passage across the night sky periodically moves it closer to certain stars and objects.
To experience a lunar encounter, such objects must be within a region of sky approximately 10° wide, centred on the ecliptic.
Over recent months, the Moon has been making relatively close passes of the Pleiades.
Occultations of the cluster will eventually occur, the visibility of which will be down to whether they happen at night with the Moon above the horizon.
Observing the Moon and Pleiades
While the Pleiades itself is normally visible with the naked eye, in this case the proximity of such a bright Moon to the much dimmer cluster stars will render the alignment unseen.
Binoculars should fare better, with the brighter cluster stars of the Pleaides easily visible to the north of the Moon.
A telescope will do better still, bringing out many of the cluster stars near the Moon.
Using a telescope, it should be possible to see the Moon glide in front of some of the Pleiades' southern outliers, offering an excellent opportunity to practise some occultation timing observations.
These are relatively easy to do, but can catch you out if you’ve never seen one before.
Since they’re points of light, stars disappear in an instant behind the airless edge of the Moon – so fast that it’s common to be watching a star intently and blink for an instant, only to find the star disappeared during your blink!
If it’s clear on the evening of 19 October and you fancy making timing observations of the Moon passing by the Pleiades, you can find more information in our guide on how to observe lunar occultations.
If you observe or photograph the Moon and its Pleiades encounter, share your observations and images with us via contactus@skyatnightmagazine.com.
