Akashi Municipal Planetarium

实用信息

• Science museum
• Opening hoursVaries by day
• Under 1 kmfrom Akashi center
• Official site
• 4.4 / 5732 reviews
• Akashi

Standing on Japan's Time Meridian

In 1886, Japan adopted the 135° East meridian — exactly nine hours behind Greenwich — as the reference line for its standard time. The city of Akashi sits right on that line, and in 1960 it built this museum directly on top of it. The tower's vertical axis is the meridian itself, marked at ground level by a line embedded in the floor near the entrance. Look down as you walk through, and you are crossing from one side of Japan's time to the other.↗↗

Beside the entrance gate stands a replica of an ancient water clock (漏刻, rokei), a device that measured time by the regulated flow of water through interconnected basins. It traces Japan's first recorded time announcement back to Emperor Tenji in 671 AD — a moment honored each year on June 10, Time Commemoration Day, which is also the anniversary of this museum's opening. The water clock keeps time directly above the meridian line, a poetic link between the oldest and newest ways of measuring hours in Japan.↗↗

On the floor of the entrance lobby, 25 ceramic tiles form a three-meter celestial map depicting 53 constellations based on a 17th-century Hevelius star atlas. Nearby, tanks of descendants of the space medaka — tiny fish that became the first vertebrates to reproduce in orbit aboard Space Shuttle Columbia in 1994 — offer an unexpectedly charming encounter.

A Living Planetarium Legend

The star of the show — literally — is a Carl Zeiss Jena Universal 23/3 projector that has been running since the museum opened in 1960. It survived the devastating 1995 Great Hanshin-Awaji Earthquake completely unscathed while the building around it was shattered; when the museum reopened in 1998, that star projector became a symbol of recovery. By 2012 it had logged the longest continuous operation of any planetarium machine in Japan, and the fifth-oldest active large projector worldwide.↗↗

The 20-meter dome seats about 300 visitors and combines the traditional hand-operated optical projector with modern digital systems added in 2017, all guided by live narration from the museum's own curators. Programs rotate monthly with themes ranging from tonight's sky to children's stories about shooting stars. A beloved annual tradition, the Sleep Planetarium event, invites tired adults to bring pillows, drift off under projected stars, and receive a certificate — either for a full snooze or a valiant all-nighter if they stayed awake.↗↗

From the Sundial Terrace to the Tower Observatory

The exhibition floor on level 3 explores the physics of timekeeping and the architecture of the solar system with hands-on models, historical instruments, and interactive displays. Level 4 opens onto a sundial plaza where you can check the sun's position with your own eyes, alongside a children's room for younger visitors.↗↗

The real revelation is higher up. Ride the elevator — or climb the spiral stairs if you are feeling adventurous — to the 13th and 14th floors. From 54 meters, the view sweeps 360 degrees: the Akashi Kaikyo Bridge dominates one direction, sailing ships cross the strait below, Awaji Island's green ridgelines float to the south, and the Rokko mountain range stretches eastward. Red lines painted on the floor and pillars of the observation room show the exact path of the meridian line as it climbs the tower.↗

Above the windows on the 14th floor hang 24 world clocks, each set to a different time zone, offering a quiet reminder of this building's unique role — the point from which all Japan's clocks are synchronized. The south face of the tower carries a clock with a 6.2-meter diameter dial, visible from passing trains on the Sanyo Line and the expressway over the strait. This tower clock has been replaced twice: the original from 1960 gave way in 1978, and the second was frozen at 5:46 AM by the 1995 earthquake before the current third-generation model took its place in 1997.

Practical Information

The museum is open 9:30 AM to 5:00 PM (last entry at 4:30 PM), closed Mondays. Admission is 700 yen for adults, and free for high school students and younger — making it one of the most family-friendly science destinations in the Kansai region. Your ticket covers the planetarium show, all exhibition floors, and the observation deck.↗↗

Planetarium shows run approximately every 90 minutes starting at 11:30 AM on weekdays and from 10:00 AM on weekends and school holidays, each lasting about 45 minutes. Most general-admission shows use a same-day ticket system distributed at the front desk from opening time, so arriving early to secure a seat for your preferred show is wise.↗↗

The nearest station is Sanyo Electric Railway's Hitomaru-mae, about a 2-minute walk to the north. From JR Akashi Station, it is roughly a 15-minute walk east. Parking on-site accommodates about 90 cars at 200 yen for the first two hours. On weekends and during holiday periods the lot can fill quickly.↗↗

The building is designated a National Registered Tangible Cultural Property, recognized for its distinctive architectural silhouette combining the domed planetarium hall and slender clock tower. It was rebuilt and reopened in 1998 after the earthquake and underwent a major renovation reopening in July 2026. The facility is operated directly by Akashi City and maintains its own curatorial staff.

Exploring the Meridian Trail

Akashi scatters a series of meridian markers along the 135° East line that you can visit on foot. South of the planetarium, the Sanyo Railway station platform at Hitomaru-mae has Japan's only train station marked directly on a time meridian. The National Route 2 roadside marker, the 1910 Dai-Nihon Central Standard Time Meridian stone — the country's first such monument — and the quirky 1930 Dragonfly Marker shaped like Japan's folk name for the archipelago are all within a pleasant short walk. The planetarium itself makes a great starting point or terminus for this meridian pilgrimage.↗