Venus to Vanish Behind the Moon in Rarely Visible Occultation Today - Tempo.co English
TEMPO.CO, Jakarta - An eclipse-like occultation will cause the planet Venus to appear to vanish temporarily behind the Moon when viewed from Earth today, September 14, 2026. According to Yatny Yulianti, an astronomer at the Bosscha Observatory in Lembang, West Java, Indonesia, the occultation of Venus by the Moon is not an astronomically rare event, as there are several such occultations this year alone. "However, the opportunity to witness it from specific locations is quite limited," she told Tempo on Friday, September 11, 2026.
This is evident in the September 14 occultation; only observers in western and central Indonesia will be able to witness the event using telescopes or the naked eye. Even then, viewing conditions range from excellent to extremely difficult depending on the location.
Based on an interactive Venus occultation map created by the Bosscha Observatory, the western region—specifically the island of Sumatra—falls into the "excellent" and "good" categories. From these areas, observers can witness the full sequence: Venus appearing, disappearing, and then reappearing.
Meanwhile, half of Java and the western part of Kalimantan are classified as "difficult" to "extremely difficult" viewing zones. In these areas, Venus will not be seen reappearing because it will have already dipped below the horizon.
During the occultation, the bright crescent Moon will pass in front of Venus, obscuring the planet—popularly known on Earth as the Morning Star or Evening Star. Occurring in the western sky after sunset, the event generally takes place between approximately 19:30 and 20:43 WIB (Western Indonesian Time).
Banda Aceh is an example of an optimal viewing location for tonight's Venus occultation. At an altitude of 19.4 degrees above the horizon, Venus will begin to disappear at 19:29. It will reappear 71 minutes later—at 20:41—at a different position: 2.8 degrees above the horizon.
The further south one goes—from Padang down to Lampung—the more difficult it becomes to spot Venus reappearing after it vanishes. The same applies to locations on Java, such as Jakarta and Bandung.
According to Yatny, other observational challenges include weather conditions and the fact that both the Moon and Venus will be at relatively low altitudes above the horizon. “Therefore, observers require an unobstructed view toward the west and reasonably good atmospheric conditions,” she said.
Muhammad Yusuf, an occultation researcher at Bosscha Observatory, added that the varied nature of Venus occultation observations across Indonesia stems from differences in viewing angles. Furthermore, because Venus’s rise time in the late afternoon is close to its setting time, some regions would be unable to see the planet re-emerge after being obscured by the Moon. “At the time of the occultation, Venus also appears as a crescent,” he stated in a podcast on September 10, 2026.
Bosscha Observatory plans to observe and livestream the Venus occultation, deploying six astronomers and a portable telescope. They will coordinate their observations with over a dozen other parties, ranging from university observatories in various regions to astronomy communities and individual observers.
These participants are spread across locations including Bangkok, Aceh, Padang, Medan, Bengkulu, Lampung, Banten, Yogyakarta, Semarang, Lamongan, Kudus, Pasuruan, and Kupang. “This joint observation serves as a collaborative exercise for Indonesia’s astronomy network and offers significant educational value regarding how the positions and movements of celestial bodies result in the different views seen from various locations,” said Yatny.
