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Products (Precision Instrument - Optical Instrument)

Ohira Tech: Optical Planetarium Projector MEGASTAR-IIA


A planetarium projector is a device used to project the night sky onto a dome-shaped ceiling.

Planetarium projectors use various projection methods, but the most popularly used is optical technology, which makes use of a star globe and a star plate. The star plate is a circular disk covered in holes so tiny they are invisible to the naked eye; some are mere microns in width. Light shines through these holes from the light source, travel through the star globe lens, where the focus is adjusted, and is then projected onto the dome ceiling, which can be a distance of up to 20m in larger planetariums.

The location of these tiny holes, opened in the star plate, are calculated with extreme accuracy in order to correctly project the night sky onto the dome-shaped ceiling; the size of the holes is also adjusted according to how brightly the light representing each star should be projected. Holes opened in the star plate number in the several thousand for smaller devices. More recent, larger projectors can have several million. Clearly this cannot be achieved without the most precise of technology.

Japan is the world-leader in manufacturing technology for optical planetarium projectors, particularly in precision technology. Fifty percent of the global production share is held by Japan’s GOTO INC. and KONICA MINOLTA Japan. Japan’s planetarium market sets the standard for the rest of the world, and the projector that emerged above the top of the field in Japan is the revolutionary MEGASTAR planetarium series, created by Ohira Tech Ltd.

Before the MEGASTAR, even the most advanced planetarium projectors were only able to project several tens of thousands of stars. By contrast, the technology used in the MEGASTAR allowed it to project 1.7 million stars. It could show stars up to a magnitude of 11.5; stars so distant and so faint that they cannot be seen at all by the naked eye even in the darkest night sky. This stunning level of accuracy brought the night sky view that could be recreated by a projector much closer to the real thing than any other planetarium before it. In particular, the way the MEGASTAR was able to present the Milky Way was revolutionary. Instead of seeing just a hazy band of light, the MEGASTAR allows the Milky Way to be viewed as huge clusters of stars that cannot be seen by the human eye. Despite the amazing scale and clarity of its projections, the MEGASTAR is compact, at just 46 cm in diameter and 27 kg in weight.

The MEGASTAR, however, was not thought of or created by a research at a major company or university. Instead, it was built by a man with a lifelong love of planetaria, who developed the MEGASTAR over many years of trial and error. That man was Takayuki Ohira, and he alone produced the star plate (something previously thought impossible for an individual), by developing a device that exposes the plate to a photoresist using laser technology, thereby creating photographic film. Ohira’s creative ability and his success in development his unique planetarium technology are truly remarkable.

(Ohira Tech Ltd.)
Dome Diameter Range 15~22m flat/tilt dome
Number of Stars 1 million ~ 20 million
Clusters & Nebulae over 170
Projection Type 32 Optical projection units
Light Source Ultra bright LED light source(lamp life expectancy 30.000 hours)
Dimming Electronic contro(l PWM) 0-100%
Shutter External shutter/Electronic shutter
Motion Time motion:Diurnal, Annual, Precession
Location motion:Longitude, Latitude( Full sphere)
Option: Extraterrestrial position