The month of the Earth’s aphelion
On July 6 at 5:39 pm, the Earth is in aphelion of its rotation around the sun, that is to say at the point farthest from the Sun on its orbit, 152,097,701 km (or ~1.017 au – astronomical unit). Indeed, its orbit describes an ellipse and not a circle around the sun.
This is the time of year when the orbital speed of the Earth around the Sun is lowest : 29.291 km/s (105.448 km/h)
- In the sky, the sun is at the beginning of the month in front of the constellation of Gemini : on the right thigh of Castor on July 1 and then on the right elbow of Pollux on July 14. In the second part of the month, it keeps moving to place itself in the middle of the constellation of Cancer at the end of july.
- Venus keeps shining above the western horizon, the first visible celestial body after sunset, still quite late at the beginning of the month. The Moon makes a discreet visit on July 17 with its very thin crescent and its ashen light.
In July, the Summer Triangle occupies the southeastern part of the sky at the beginning of night. It consists of:
- Vega, α Lyrae, white star in the constellation of Lyra
- Deneb, α Cygni, white supergiant star, from the constellation of Cygnus
- Altaïr, α Aquilae, white star in the constellation of Aquila, closest to the southern horizon
At the same time, the constellation of Scorpius, led by Antares (a red supergiant at the end of its life), passes over the southern horizon. The whole constellation is visible only with a perfectly clear point of view in this direction.