Seiko Astron is positioned as a high-precision model centered around GPS solar. Current models include the 5X series, the 3X series GPS solar, and solar radio-controlled models, offering a wide range of options depending on the exterior and movement configuration. In this article, we will summarize the technical features and lineup of Seiko Astron, and explain five models from the current collection.
1. What is Seiko Astron?
Features of the Seiko Astron
Seiko Astron was released in 2012 as the world's first GPS solar watch, and remains a symbol of Seiko's cutting-edge technology. Its greatest feature is that it obtains not only time information but also location information from GPS satellite signals, automatically adjusting the time to match the current time zone.
While conventional standard radio-controlled watches rely on signals from domestic and international radio stations and are therefore only available in certain areas, the Seiko Astron GPS Solar can obtain time information from almost anywhere on Earth, making it a useful option for users who travel frequently abroad.
Furthermore, all Seiko Astron models are equipped with a solar power generation system, eliminating the need for battery replacement and allowing for stable use over a long period of time.
In addition, many models use lightweight titanium for the case material, and another attractive feature is that scratch resistance is enhanced through Seiko's unique ``Super Black Hardening Treatment'' and surface treatment technology (DiaShield).
Seiko Astron Lineup
Seiko Astron is available in several series based on movement, with the GPS solar 5X and 3X series, as well as solar radio-controlled timekeeping models that support standard radio waves, making this lineup easy to choose based on your intended use and preference for fit.
ネクスター(NEXTER)
The Nexter series was introduced in 2022 as a new design standard for Seiko Astron. It features a case design that combines straight lines and surfaces, with an exterior design carefully calculated to ensure that the structure is clearly visible depending on how the light hits it. The bracelet and case are also designed to enhance unity, ensuring stability when worn.
The dial has been designed with visibility in mind, with the thickness and shape of the indexes and hands revised. The layout of the subdials and indicators has also been streamlined, allowing for a clear view of the GPS solar multi-function display.
Nextar is used in both the 5X and 3X series and is the core series of Seiko Astron.
For more information about the NEXTER series,CLICK HEREPlease refer to.
The Nextar features an eye-catching, sharp design based on the concept of "Solidity & Harmonic." The photo shows the third model in the series, the "SBXD013," released in 2023. GPS solar (Cal. 3X62). Runs for approximately six months on a full charge (approximately two years in power save mode). Ti case (diameter 41.2mm, thickness 12mm). Water resistant to 10 bar. Priced at 275,000 yen (tax included).
The movements are "GPS Solar 5X", "GPS Solar 3X", and "Solar Radio Wave".
Current Seiko Astron models can be broadly classified into three types depending on the movement they are equipped with.
GPS Solar 5X
The 5X series movement is the top of the Astron line, and uses a structure that Seiko describes as "the world's smallest and thinnest GPS solar movement."
This movement is
- Fast time zone adjustment
- Dual time display
- Automatic time adjustment (daily)
・Reception control by smart sensors
It has the following features:
Time zone adjustments can be completed in as little as three seconds, with the aim of reducing stress when traveling.
Time zone adjustments can be completed in as little as three seconds, with the aim of reducing stress when traveling.
In addition, an independent drive motor controls the movement of the hands, allowing instant switching between local time and home time, making dual time management intuitive.
The SBXC151 features the GPS solar movement 5X83, which has a dual time display and a stopwatch function capable of measuring 1/20 seconds. GPS solar (Cal. 5X83). Runs for approximately 6 months on a full charge (approximately 2 years in power save mode). Ti case (diameter 43.3mm, thickness 13.4mm). Water resistant to 10 bar. Price: 308,000 yen (tax included).
GPS Solar 3X
The 3X series movements have the same GPS satellite radio wave reception function as the 5X series, but are more compact in design.
While maintaining the performance required for GPS reception, the number of hands and drive system have been streamlined to reduce the size and thickness of the case, resulting in a model with a reduced case diameter and thickness.Although it is a GPS model, the design is focused on comfort.
The 3X series is clearly differentiated as a lineup aimed at users who simply want the convenience of GPS, and there are models in the Nextar series that are equipped with 3X series movements.
The SBXD031 is equipped with the GPS solar movement 3X32, which improves GPS signal reception sensitivity. The ability to use a metal bezel gives it a sophisticated look. GPS solar (Cal. 3X32). Runs for approximately six months on a full charge (approximately two years in power save mode). Ti case (diameter 41mm, thickness 13.1mm). Water resistant to 10 bar. Price: 247,500 yen (tax included).
ソーラー電波
The solar-powered radio-controlled movement uses standard radio waves instead of GPS to adjust the time. It is compatible with Japan's JJY (40kHz/60kHz) and overseas radio stations, and has the advantage of being easy to receive even indoors in compatible areas.
Equipped with a mechanism that automatically adjusts the time based on reception of standard radio waves, and combined with solar power generation, it ensures high practicality. It is often used by users who do not need GPS functionality and in models intended for business use.
The SBXY031 features a radio-controlled solar movement that receives standard radio waves from Japan, China, the United States, Germany, and the United Kingdom. It's radio-controlled solar (Cal. 7B72). It lasts for approximately nine months on a full charge (approximately two years in power save mode). It has a Ti case (39mm diameter, 9.6mm thick). It's water resistant to 10 bar. It's priced at 137,500 yen (tax included).
Seiko Astron Technology
The technological foundations that make up the Seiko Astron can be broadly divided into three: GPS satellite signal reception, standard radio wave reception, and solar charging (photovoltaic power generation).
Both are core features in understanding the brand's characteristics.
GPS satellite signal reception
The core technology of Seiko Astron is its ability to receive time and location information transmitted from GPS satellites and automatically adjust the time to match the current time zone, no matter where you are on Earth.
GPS satellites are equipped with atomic clocks that measure time accurately, and by receiving these signals, Seiko Astron GPS solar models can access extremely precise time information.
This mechanism, which has been continued since the Seiko Astron in 2012, allows time adjustment even in areas where standard radio waves cannot reach, making it a design suitable for users who travel frequently.
The 5X series movements feature faster time zone correction speeds and smart sensor control that adapts to the reception environment, making them more convenient for practical use.
標準電波受信
Seiko Astron also offers models that are equipped with standard radio wave reception (solar radio waves) rather than GPS functionality.
Standard time signals are transmitted by two stations in Japan: Fukushima (40kHz) and Kyushu (60kHz), and there are also stations overseas that can receive them.
Compared to the GPS model, the standard radio wave model:
Easy reception even indoors
- Compact structure and highly practical
These are some of the advantages.
Since it corrects the time based on the reception area rather than automatically switching time zones, it is particularly suitable for users who intend to use it in Japan.
The model is equipped with a mechanism that automatically corrects the time according to the radio wave reception conditions, making it suitable for stable everyday use.
solar charging
All Seiko Astron models are solar-powered (photovoltaic).
The solar panel under the dial receives light and generates electricity, ensuring stable operation over a long period of time.
This eliminates the need for battery replacement like with regular battery-powered watches, and the common benefit of easy power management is that both GPS and radio-controlled models have the same advantage.
Seiko has been working on solar charging technology for many years, and its watches are characterized by their high power generation efficiency even in low light environments.
It also comes with practical features such as controls to prevent overcharging and long-term operation after a full charge.
< h2>2. 5 Recommended Seiko Astron Models
The current Seiko Astron models are broadly divided into the GPS solar 5X and 3X models, and solar radio-controlled models. Here we introduce five carefully selected recommended models.
"SBXC175" - The appeal of the high-end 5X series
GPS solar (Cal. 5X83). Runs for approximately 6 months on a full charge (approximately 2 years in power save mode). Ti case (diameter 44.1mm, thickness 14.4mm). Water resistant to 10 bar. Price: 247,500 yen (tax included).
The SBXC175 is a model in the Nextar series equipped with the 5X53, the top-of-the-line GPS solar movement, and is positioned as a technological symbol of Seiko Astron.
The 5X53 stands out for its design with travel in mind, featuring faster time zone adjustment, instant switching between home time and local time, and smart sensor control.
The exterior adopts Nextar's distinctive three-dimensional design, emphasizing the surface structure of the case and bracelet. Made from lightweight titanium, the surface is treated with Seiko's proprietary DiaShield coating for increased scratch resistance.
The dial displays multiple pieces of information in an organized manner, and the indexes and hands are finished for easy visibility, making the complexities inherent to GPS solar watches easy to handle.
Among the current Seiko Astron collection, this model can be considered a "reference point" in terms of both technology and appearance.
"SBXC181" - A sporty and easy-to-handle 5X model
GPS solar (Cal. 5X83). Runs for approximately 6 months on a full charge (approximately 2 years in power save mode). Ti case (diameter 43.3mm, thickness 13.4mm). Water resistant to 10 bar. Price: 33 yen (tax included).
The SBXC181 is a model that also uses the 5X53 movement, but adds a sporty touch to its exterior. It features a design that accentuates the ridges of the case, and the dial has a multi-layered structure that organizes the placement of the subdials.
The functions of the 5X53 are the same as those of the SBXC175.
- Fast time zone adjustment
・デュアルタイム
・Automatic time correction
・Reception control by smart sensors
It has the following features:
The bracelet shape is designed with fit in mind, contributing to comfort when worn for long periods of time, and the surface is treated with DiaShield to ensure scratch resistance and maintain its appearance.
Despite its sporty appearance, it can also be used for business purposes, making it one of the most versatile models in the 5X series.
"SBXC159" - A model symbolizing the Nexter series
GPS solar (Cal. 5X83). Runs for approximately 6 months on a full charge (approximately 2 years in power save mode). Ti case (diameter 42mm, thickness 12.4mm). Water resistant to 10 bar. Price: 247,500 yen (tax included).
The SBXC159 is the iconic model of the Nexter series, and has the best balance of the 5X series' functional configuration and exterior design.
The case is a combination of straight lines and surfaces, adopting a design that clearly shows the contours of the shape, typical of Nextar. The bracelet is designed to be one with the case, increasing stability when worn.
The 5X53 movement is characterized by its fast switching speed between local time and home time, making it particularly easy to use when traveling abroad. It also has high accuracy in restoring the hands to their original positions after receiving GPS signals, and Seiko officially emphasizes this control precision.
As the "central position" of the Nexter, this model is suitable for users who place importance on the overall balance between appearance and functionality.
"SBXY101" - A practical model with standard radio waves and solar power
Radio-controlled solar (Cal. 7B62). Runs for approximately 9 months on a full charge (approximately 2 years in power save mode). Ti case (36mm diameter, 8.7mm thick). Water resistant to 10 bar. Price: 165,000 yen (tax included).
The SBXY101 is a representative model in the series that uses the solar-powered radio movement 8B63, which supports standard radio waves, and corrects the time using radio waves rather than GPS.
It supports reception of Fukushima stations (40kHz) and Kyushu stations (60kHz) in Japan, and also major stations overseas.
Unlike GPS, it does not use location information, so time zones must be changed manually, but the advantage is that it is easy to receive indoors, and it is easy to maintain stable accuracy during everyday use.
The dial is designed for easy visibility, with the date and reception status indicators neatly arranged. The case diameter is small, making it easy to handle, especially for business use.
Combined with solar power generation, it is suitable for long-term use, and can be said to be a model that is "specialized for practicality" among Seiko Astron models.
"SBXD035" - Standard model of the 3X series
GPS solar (Cal. 3X32). Runs for approximately 6 months on a full charge (approximately 2 years in power save mode). Ti case (diameter 41mm, thickness 13.1mm). Water resistant to 10 bar. Price: 247,500 yen (tax included).
The SBXD035 is equipped with a GPS solar 3X22 movement and is one of the most compact and comfortable models in the Seiko Astron lineup.
The 3X22 features a structure that reduces the diameter and thickness of the movement while maintaining time correction via GPS satellite signal reception, resulting in a thinner and lighter case.
The dial has a simple display configuration, and the design balances visibility while ensuring the convenience of GPS solar.
The exterior has a surface structure that follows the lineage of the Nexter, and combines a light and airy size with a modern design.
This is a watch that is perfect for users who want the convenience of a GPS model in a size that is easy to use on a daily basis.
3. Summary: Finding the Astron that's right for you
Seiko Astron is a model that systematizes technologies for achieving accurate timekeeping, centered around GPS solar and solar radio wave technology. With three types of movement configurations—5X series, 3X series, and solar radio wave—there is a wide range of models to suit users from frequent travelers to those who prioritize everyday use.
The introduction of the Nextar series has streamlined the exterior design, clarifying the "Seiko Astron standards" in terms of case shape, legibility, and wearability. The five watches featured here are all current models that reflect Seiko's technological background and functional design, making it easy to compare them depending on their intended use.
By understanding the core technology of Seiko Astron and the different combinations of exteriors and movements for each series, it will be easier to choose a model that suits your usage environment.
