The planets during the new moon
The Moon will leave us a very dark sky during this weekend as the new moon will take place on Monday, July 17. So let's take advantage to enjoy the planets, there are five visible to the naked eye and forming beautiful scenes in the sky.
At sunset
The Moon will not be an obstacle to observe the three rocky planets of the solar system, brothers of the Earth, which are visible in the evening twilight, since we are on the eve of the next new moon, which will happen on July 17 in the constellation of Gemini.
One hour after sunset, it is advisable to face northwest in a place with a clear horizon and free from light pollution.. Extremely bright Venus dominates the show, but a little higher (about ten degrees away) we can also see the discreet reddish glow of Mars. And, between both planets, we can distinguish the star Regulus (from the Latin “little king”), the brightest in the constellation Leo, which exhibits a beautiful bluish glow.
Jupiter and the Pleiades, July 15 and 16
Venus reaches its maximum brightness of the year these days as it is extremely close to Earth, only 55 million kilometers away (just over a third of the Earth-Sun distance).. It is so close that, with binoculars, it is possible to see the phase it is in, with only a fine arc of the planetary disk illuminated by the Sun.. You have to take advantage of these days to observe it because as the month progresses, its apparent distance from the Sun will decrease and, at the end of the month, both stars will be practically aligned and will disappear together at sunset.. Venus will not be visible until late August when it will reappear in the eastern sunrises.
This weekend Mars continues to appear much weaker than Venus, because in recent months, as it orbits the Sun, it has been moving away from Earth. It is now 2.3 times farther than the Sun and 6.4 times farther than Venus.. This great distance, together with its own characteristics, makes Mars now appear about 400 times less bright than Venus.
To complete this picture, we can also observe the always elusive Mercury, very low above the horizon, but a little higher with each passing day from July 16 to 21.. To observe it, it is very important to stand before a horizon that is well free of obstacles such as trees or buildings.
At dawn
Early risers who look at the sky before sunrise will be lucky enough to see two giant planets. To do this, we recommend looking northeast one or two hours before solar rising, that is, around 5 or 6 in the morning.
Jupiter will already be low above the horizon, but despite the colors that come on at dawn, this giant planet is so extremely bright that it can be seen without difficulty.. These days in the middle of the month, Jupiter rises at about 2:00 a.m. (peninsular time) and from that moment it is possible to see its calm ascent over the horizon. To its left, as we look at the sky, we can see the Pleiades (or “the seven sisters”), a beautiful stellar cluster that has been the subject of legends and stories invented by practically all civilizations and throughout the entire history of mankind. .
We have been able to see the thin edge of the waning Moon in the sunrises of this past week, on Saturday the 15th its position in Taurus is very close to that of the great reddish star Aldebaran. On the unilluminated lunar disk we will be able to observe the always delicate ashen light, a glow that comes from the reflection of sunlight on our planet, which intrigued astronomers for centuries. The first to give a scientific explanation of its origin was Galileo.
To the south is Saturn, which these days rises in the east at sunset and remains visible throughout the night.. The giant with the rings rises about 40 minutes earlier each day and, therefore, if we look at it one night after another at the same time, we will see that it is gaining in height with each passing day.
If you are lucky enough to observe Saturn with the help of a small telescope, you will be able to get a beautiful view of its fascinating rings because, now, the inclination of these is small, making the perspective on the planet particularly beautiful.. And also with a telescope, it is now possible to observe Neptune whose apparent position in the sky is halfway between Jupiter and Saturn.. Finally, such a telescope would also be useful for looking at Uranus, which lies to the east of Jupiter.
These hot summer nights are not the most favorable for professional astronomy because they are short and, in addition, the high temperatures increase atmospheric turbulence.. But, for the average citizen, who spends more time outside enjoying the good weather, these are excellent nights to look up at the sky, especially at twilight, and thus enjoy these beautiful celestial images that remind us of our origins. and our place in the cosmos.
Rafael Bachiller is director of the National Astronomical Observatory (National Geographic Institute) and academic of the Royal Academy of Doctors of Spain.