Citizen Tsuki-yomi A-T Moonphase 43mm Eco-Drive Watch #BY1010-57L
39-BY1010-57L
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Model Reference: BY1010-57L
Overview
The Citizen Tsuki-yomi BY1010-57L is the vibrant, oceanic counterpart to the silver-dial moon phase models. This timepiece is named after Tsukuyomi, the Japanese moon god, and represents a world-first in horological technology: an analog moon phase that synchronizes via radio signals. The standout feature is its deep blue textured dial, which evokes the image of the moon reflecting off a midnight sea. This model combines the romanticism of celestial tracking with the absolute precision of Atomic Timekeeping, housed in a sharp, modern stainless steel architecture.
Technical Specifications
Case Size: 43mm (Structured, ergonomic profile)
Case Material: Silver-Tone Stainless Steel (Multi-faceted brushed and polished surfaces)
Movement: Eco-Drive (Caliber H874; World’s first radio-controlled automatic moon phase movement)
Crystal Type: Sapphire Crystal (Anti-reflective coating for high-contrast viewing)
Water Resistance: 100 Meters (10 ATM / 333 feet) — Suitable for swimming and professional daily wear
Dial: Vivid blue with a "Lunar Surface" relief texture and a moon phase aperture at 6 o'clock
Bezel: Fixed, polished silver-tone stainless steel
Strap: Silver-tone stainless steel link bracelet with a fold-over clasp
Special Features
"Luna Program" Automatic Calculation: This model utilizes Citizen’s proprietary internal logic to calculate the moon phase. By receiving atomic radio signals, the watch automatically aligns the moon phase disc, ensuring it is never out of sync with the actual lunar cycle.
Blue Lunar Topography: The dial features a specialized embossing that mimics the craters and highlands of the moon. In this 51L variant, the deep blue color adds a layer of depth, making the silver-tone hands and indices appear like moonlight on water.
Hemisphere Customization: The watch offers the unique ability to display the moon phase as seen from either the Northern or Southern Hemisphere, a rare feature in any moon phase timepiece.
Global Atomic Timekeeping: Automatically synchronizes with radio towers in North America, Europe, Japan, and China for laboratory-grade time and date accuracy.
Perpetual Calendar: A high-complication feature that automatically adjusts for the varying days in a month and leap years until February 28, 2100.
World Time Functionality: Allows for rapid jumping between 26 world time zones by aligning the second hand with the city codes on the outer dial ring.
Eco-Drive Sustainability: Powered by any light source, natural or artificial, ensuring the high-drain moon phase and radio-control features function indefinitely without a battery change.
Integrated Sub-Dial Indicators: The sub-dial at 12 o'clock provides a dual-function readout for the current power reserve and the light-charging efficiency (Light Level Indicator).
Professional Luminance: The hands and indices are filled with premium lume, providing a cool blue-green glow that mirrors the astronomical theme of the watch.
Overview
The Citizen Tsuki-yomi BY1010-57L is the vibrant, oceanic counterpart to the silver-dial moon phase models. This timepiece is named after Tsukuyomi, the Japanese moon god, and represents a world-first in horological technology: an analog moon phase that synchronizes via radio signals. The standout feature is its deep blue textured dial, which evokes the image of the moon reflecting off a midnight sea. This model combines the romanticism of celestial tracking with the absolute precision of Atomic Timekeeping, housed in a sharp, modern stainless steel architecture.
Technical Specifications
Case Size: 43mm (Structured, ergonomic profile)
Case Material: Silver-Tone Stainless Steel (Multi-faceted brushed and polished surfaces)
Movement: Eco-Drive (Caliber H874; World’s first radio-controlled automatic moon phase movement)
Crystal Type: Sapphire Crystal (Anti-reflective coating for high-contrast viewing)
Water Resistance: 100 Meters (10 ATM / 333 feet) — Suitable for swimming and professional daily wear
Dial: Vivid blue with a "Lunar Surface" relief texture and a moon phase aperture at 6 o'clock
Bezel: Fixed, polished silver-tone stainless steel
Strap: Silver-tone stainless steel link bracelet with a fold-over clasp
Special Features
"Luna Program" Automatic Calculation: This model utilizes Citizen’s proprietary internal logic to calculate the moon phase. By receiving atomic radio signals, the watch automatically aligns the moon phase disc, ensuring it is never out of sync with the actual lunar cycle.
Blue Lunar Topography: The dial features a specialized embossing that mimics the craters and highlands of the moon. In this 51L variant, the deep blue color adds a layer of depth, making the silver-tone hands and indices appear like moonlight on water.
Hemisphere Customization: The watch offers the unique ability to display the moon phase as seen from either the Northern or Southern Hemisphere, a rare feature in any moon phase timepiece.
Global Atomic Timekeeping: Automatically synchronizes with radio towers in North America, Europe, Japan, and China for laboratory-grade time and date accuracy.
Perpetual Calendar: A high-complication feature that automatically adjusts for the varying days in a month and leap years until February 28, 2100.
World Time Functionality: Allows for rapid jumping between 26 world time zones by aligning the second hand with the city codes on the outer dial ring.
Eco-Drive Sustainability: Powered by any light source, natural or artificial, ensuring the high-drain moon phase and radio-control features function indefinitely without a battery change.
Integrated Sub-Dial Indicators: The sub-dial at 12 o'clock provides a dual-function readout for the current power reserve and the light-charging efficiency (Light Level Indicator).
Professional Luminance: The hands and indices are filled with premium lume, providing a cool blue-green glow that mirrors the astronomical theme of the watch.
Estimated production and handling times vary and are indicated individually on each item's page. All online orders are shipped with Canada Post priority mail unless otherwise arranged. Shipping transit times to Canada and the USA is around 3-6 business days depending on the location. Upon receiving successful payment for a product, we will provide an estimated delivery date for the product to be shipped via email.
