TAIPEI (Taiwan News) — The Taipei Astronomical Museum announced that this year’s autumnal equinox is on Saturday (Sept. 23).
The autumnal equinox marks the start of autumn, where days in the northern hemisphere become shorter than nights, per UDN. It is an astronomical event when the sun moves to 180 degrees longitude, shining directly over the equator.
In Taipei, the daytime will become shorter by 13 minutes approximately 10 days after the autumnal equinox. During this time, astronomical photographers can look forward to stunning nighttime sights.
Zodiacal light can be observed two to three hours before sunrise as long as there is no light pollution. Zodiacal light is a cone-shaped glow extending from the eastern horizon caused by sunlight diffused by fine dust particles in the solar system.
The Taipei Astronomical Museum noted that Mercury, the tiniest planet in the solar system, is typically difficult to see because it is closest to the sun and obscured by sunlight. Mercury's brightness will increase dramatically on Friday (Sept. 22), allowing it to be seen at 5 a.m. before sunrise each day.
Mercury will be at its greatest western elongation to the Earth. With the naked eye, one can search for a needle-like white figure at a low altitude in the east, just below Venus.