Mercury is set to become the most distant planet from the sun in our morning sky on August 19th, making it an ideal viewing opportunity for early risers. Due to its extremely close orbit around the sun, Mercury can be challenging to spot, especially when compared to planets like Mars, Jupiter, Saturn, Uranus, and Neptune.
Astronomers call this phenomenon the “greatest western elongation,” which occurs on August 19th at 8:25 a.m. EDT (12:25 GMT). This is the best time to catch Mercury in its morning appearance, although it will only be visible for a short period. For observers in New York, Mercury will rise about 16 degrees above the eastern horizon by the time the sun appears.
To spot Mercury, look east in the hour before dawn and search among the stars of the constellation Cancer. The planet will shine low among these stars, with Venus and Jupiter forming a line to its upper right, below a thin crescent moon. However, be sure to find a location with an unobstructed view to the east to increase your chances.
Mercury’s brightness will start to decrease as it rises above 10 degrees on the horizon – roughly the width of your outstretched fist. If you have access to a telescope with an aperture of 4 inches or more, you may be able to observe Mercury’s moon-like phases, but avoid pointing the telescope at the rising sun, which can cause permanent damage.
On August 19th, Mercury will appear as a bright “morning star” to the naked eye. As you view the planet through a telescope, you’ll see its crescent shape, although be cautious not to point your telescope near the sun.
Source: https://www.space.com/stargazing/look-for-mercury-in-morning-sky-as-it-hits-peak-distance-from-sun-aug-19