Core Points - Mercury will have its best observation opportunity during the western elongation on August 19, 2023, with favorable conditions for the public to view the planet if the weather permits [1][4] - Mercury is the hardest planet to observe due to its proximity to the Sun, often being obscured by sunlight [2] - The best time to observe Mercury is during its greatest angular distance from the Sun, known as "greatest elongation," which occurs approximately every 116 days [2][4] Observation Conditions - This western elongation will allow Mercury to be seen in the eastern low sky during dawn, with a horizon height of about 18 degrees and a brightness of 0 magnitude [4] - Observers using telescopes may also see Mercury in a crescent shape, with approximately 40% of its surface illuminated by the Sun [4] - The observation opportunity is not limited to August 19; several days before and after also provide chances to view Mercury due to minimal height variation [7]

Core Viewpoint - The article discusses the upcoming western elongation of Mercury on August 19, which presents the best observation conditions for the planet this year, allowing the public to potentially view it in the early morning sky if weather permits [1][2]. Group 1: Observation Conditions - Mercury will be at a horizontal height of approximately 18 degrees at sunrise, with a brightness of 0 magnitude, making it visible to the public [2]. - The observation of Mercury is not limited to August 19; the days surrounding this date also provide good opportunities for viewing due to minimal changes in the planet's height [3]. Group 2: Characteristics of Mercury - Mercury is the most challenging planet to observe in the solar system due to its proximity to the Sun, often being obscured by sunlight [1]. - The planet completes its orbit around the Sun in just 88 days, resulting in 3 to 4 occurrences of both eastern and western elongations each year, with varying observation conditions based on its position relative to the Sun [1].

Core Points - Mercury will have its eastern elongation on July 4, 2023, providing good observation conditions for the public if the weather is clear [1][2] - Mercury is the closest planet to the Sun and is difficult to observe due to its proximity to the Sun's glare [1] - The best time to observe Mercury is during its eastern elongation when it appears in the western sky after sunset [1] Observation Conditions - This year, Mercury will have three eastern elongations, occurring on March 8, July 4, and October 30, with the first two having favorable observation conditions [2] - On July 4, Mercury's altitude will be approximately 18 degrees at sunset, with a brightness of about 0.4 magnitude [2] - Observers are encouraged to look for Mercury a few days before and after July 4, as the altitude will be higher in the days leading up to the event [2]

Group 1 - The event of Mercury accompanying the Moon on June 27 is highlighted as a noteworthy astronomical occurrence, with favorable observation conditions [1][2] - Mercury is the smallest planet in the solar system and is often difficult to observe due to its proximity to the Sun, only becoming visible during its greatest elongation, known as "greatest distance" [1][2] - This month, Mercury appears as an "evening star" after sunset, positioned in the northwest sky, while the crescent Moon will accompany it, creating a rare "star-moon dialogue" [2] Group 2 - The concept of "greatest distance" is explained, with distinctions made between eastern and western greatest distances, affecting visibility during dawn and dusk [2] - Observers are encouraged to use binoculars or small telescopes for better viewing of the Mercury-Moon conjunction, and astrophotographers are advised to capture this unique moment [2] - The nearby Beehive Cluster, a loose star cluster, can also be observed, although it may be challenging due to the remaining daylight [5]