It's the meeting of the century.
This month, the inhabitants of the Earth will be able, with a little luck, to embrace the gaze of the seven other planets of the solar system, close to each other as rarely.
At least four of them, —Venus, Mars, Jupiter and Saturn—, as well as the Moon, can be admired simultaneously with the naked eye in the night sky.
Binoculars should suffice to complete the picture with Mercury, Uranus and Neptune in the same pocket square.
Bad weather is unlikely to spoil the party: the show will last nearly two weeks!
According to calculations by the Institute of Celestial Mechanics and Ephemeris Calculation (IMCCE), the planets and the Moon will form a line that will be fully visible at the end of the night between June 14 and 27.
The maximum tightening will take place on June 22, again according to this laboratory located within the Paris Observatory.
A nice gift for the summer: the last time a similar phenomenon occurred was in December 1997, but you have to go back to January 1984 to find a spectacular event, as there are few per millennium.
The next opportunity to see this bouquet of planets will take place in November 2124, in 102 years...
How the planets "align".
If the curious will see a line, it would be misleading to speak of alignment of planets!
This would then mean that they are physically on the same axis from the Sun to Neptune, which is not the case.
But, like the Earth, these planets orbit around the star on the same plane called the ecliptic.
This is how, seen from our planet, they seem to wander over the weeks over a very narrow strip of the sky, in the constellations of the zodiac.
On rare occasions, the Earth is so placed that all its "companions" are positioned on the same side of the celestial vault and seem to be aligned.
The event is rather called "parade of the planets".
" Be alert "
To observe the whole string of stars between the east and the south, you will have to be ready very early, around 4:30 a.m., or even 4 a.m. if you choose one of the last dates of the period.
It is important to find a place where the horizon is clear, a
sine qua non
for seeing Mercury, which will appear very shortly before sunrise.
“We will have to be on the lookout, because it will not last for hours.
I would say about 15 minutes from when Mercury is high enough to be visible to the end of twilight.
We will no longer be in the dark,” warns Pascal Descamps, head of the astronomical calculations and information department of the IMCCE.
Mercury can be a challenge.
“It's always quite difficult to see her.
It is the planet closest to the Sun.
It is completely bathed in sunlight”, continues Pascal Descamps.
“It will be impossible to see it with the naked eye.
It will be necessary to use optical means such as a pair of binoculars or a small telescope.
We can find it knowing where it is: between the Sun and Venus.
Conversely, the latter will display an insolent brilliance, impossible to miss.
There will also be no difficulty in spotting the red Mars on its right, then the giants Jupiter and Saturn, and why not guessing the rings of the latter with binoculars or a telescope.
But these instruments will mainly be used to locate two tiny bluish dots.
The leftmost, Uranus, will be intercalated between Venus and Mars.
As for Neptune, it will be positioned between Jupiter and Saturn.
“That's one of the benefits of this rapprochement: using the big bright planets to find the small ones that aren't.
Uranus and Neptune are not spectacular because they are very far apart, but their appearance differs from that of a star,” says Pascal Descamps.
“We can try to distinguish them with binoculars.
The difficulty is always to find a very stable support.
Even to observe a shiny body, it is necessary to be wedged well.
It's better to use a telescope on a tripod,” he remarks.
Depending on whether one chooses to observe this great rapprochement around June 14 or 27,