Star Porrima, known as Gamma (γ) Virginis, is a binary star in the constellation Virgo.
The binary pair is made of two similar main sequence stars both about 38 lightyears from Earth.
Shining at mag. +2.7, Porrima can be seen with the naked eye in the ‘bowl of Virgo’, but to resolve it and see the two individual stars, you’ll need a telescope.
!["Constellation]("https://images.immediate.co.uk/production/volatile/sites/25/2022/03/virgo-spica-porrima-4e06d29.jpg?quality=90&resize=620%2C412" "\"virgo")
Because Porrima lies close to the ecliptic – the imaginary line followed by the Sun across the sky – it can often be seen in a lunar occultation, whereby it disappears behind the Moon from our perspective on Earth.
One such occultation is occurring on 19 March 2022 and will be viewable from the UK.
From the centre of the UK, Porrima is occulted at 05:52 UT as the sky is brightening due to the approach of dawn.
The time of occultation will vary by up to several minutes depending on location. Find out how to observe it below.
Lunar occultation of Porrima, 19 March 2022
!["From]("https://images.immediate.co.uk/production/volatile/sites/25/2022/03/porrima-occultation-label-b653f8f.jpg?quality=90&resize=620%2C516" "\"porrima")
The Moon will occult binary star Porrima on the morning of 19 March.
This will be an interesting and challenging occultation to observe because the sky will appear quite bright as sunrise approaches.
The best strategy will be to locate Porrima early, say from 04:30 UT.
The Moon’s phase will be full at the time of the occultation, so use some optical assistance to see the star, such as binoculars or a telescope finder.
At 04:30 UT, Porrima lies 0.6˚ from the Moon’s limb.
As the occultation approaches, it’ll get harder to see the star, but a telescope should still show it even though the sky is becoming blue.
Occultation disappearance occurs around 05:52 UT as seen from the centre of the UK, with reappearance occurring around 06:24 UT after sunrise.
As the occultation chord – the apparent path of the star behind the Moon – is close to the Moon’s northern limb, times will vary by a number of minutes depending on location.
If you do have clear skies, this is a fascinating event to observe, forcing you to do battle with the Moon’s glare and the bright morning twilight just before the Sun rises.
As a result of this proximity to sunrise, extreme caution must be taken when viewing this occultation.
Observing the Sun without proper certified solar equipment can seriously damage your vision. If in doubt, don’t attempt it.
This guide originally appeared in the March 2022 issue of BBC Sky at Night Magazine.