The planet Mercury reaches its highest point within the sky on Saturday morning (Sept. 23).
The closest planet to the sun, Mercury can also be the solar system’s smallest world. This implies even when it’s at its highest within the sky during its September to October morning apparition and shining brightly, the planet will probably be a troublesome spot for some amateur astronomers depending on their location. While the planet will probably be fairly shiny at a magnitude of -0.5, with the minus prefix indicating a very shiny object over Earth, it is going to still be low to the horizon.
From Recent York City, Mercury will rise on Saturday (Sept. 23) at around 6 a.m. EDT (1000 GMT), and the planet will reach 16 degrees over the horizon — its highest point within the sky — culminating at around 11:43 EDT (1542 GMT), in line with Within the Sky. The tiny planet will then set within the afternoon at around 6:13 p.m. EDT (2213 GMT).
To see it, look to the east an hour before the sun rises to seek out a yellowish Mercury between the back legs of Leo, the lion. To see it, you will need a transparent, unobstructed view of the horizon. But watch out! You’ll want to concentrate on the time the sun rises in your location and take precautions to never point any optics within the direction of the rising sun.
Related: Night sky, September 2023: What you possibly can see tonight [maps]
Because the closest planet to the sun within the solar system, Mercury is often too washed out by the sunshine from our star to be seen. The one times the planet is de facto visible from Earth and the periods when it reaches its largest separation from the sun — generally known as best elongation. This happens during points within the 88-Earth-day orbit of Mercury across the sun when the tiny planet passes between Earth and our star, something that happens roughly every 116 days — known as Mercury’s synodic period — after which speeds ahead of our planet in its more leisurely 365-day orbit.
When Mercury is visible, that is known as a period of apparition and lasts a number of weeks. The apparitions of Mercury can occur within the evening or, as is currently the case, within the mornings. The timing of the apparition of Mercury is determined by which side of the sun the planet is on because it approaches, reaches, and recedes from its best elongation.
If Mercury is to the east of the sun, it rises and sets a short while after the sun, making it visible within the later afternoon/evening and resulting in its evening apparition. Whether it is to the west of the sun, then Mercury rises and sets before the sun during its morning apparition phase. These apparitions occur alternatively.
During evening apparitions, depending on the time of the 12 months at which they occur, Mercury climbs to between 9 degrees and 21 degrees above the horizon at sunset. Again, depending on the time of the 12 months, during morning apparitions, Mercury reaches between 11 degrees and 19 degrees over the horizon at sunrise.
The present phase of Mercury’s morning apparitions kicked off on Sept. 6, 2023, when it first passed between Earth and the sun — a position astronomers call an inferior conjunction — and can last well into Oct, in line with Earth Sky.
Want to ascertain out Mercury within the early morning sky? See our guides on the best telescopes, the best binoculars, and the best telescopes for seeing planets.
And if you happen to’re seeking to take awesome photos of Mercury or the night sky basically, try our guide on easy methods to photograph the planets, in addition to our best cameras for astrophotography and best lenses for astrophotography.