Lunar Calendar and Tide Calculator


This instrument consists of a lunar calendar on one side and an abacus or tide calculator on the other. It is based on the need to to predict the time of the passage of the Tides and the intimate relationship of these with the influence of the rotation of the Moon in its orbit around the Earth.

Knowing the phases of the moon is of great cultural importance for many peoples: calendars, religious festivals, agricultural practices, etc. The tide calculator or abacus is used to calculate tide times because of its important effects on navigation, ports and fishing.


Maximum Height: 16,2cm / Diameter: 12cm / Thickness: 0,7cm

At this time, orders shipped within the United States are shipped using USPS or UPS. Tracking information will be provided via email.

International shipping is offered on case-by-case basis. Please email us at to inquire.

PEM Shop is not responsible for lost or stolen merchandise.

For our local customers, we are pleased to offer an In Store Pickup option! How it works:

  1. Shop online at

  2. At checkout, select Curbside Pickup as your shipping method. Place your order.

  3. Once we have prepared your order, you will receive an email that your order is ready for pickup.

  4. Follow the pickup instructions provided in your email. Arrive at our Store location at 161 Essex Street.

  5. Orders not picked up within two weeks of order date will be canceled and refunded.

Please Note: Please allow 2-3 days from purchase date for processing. In Store Pickup is available Thursday through Monday 10 am–5 pm.

We are pleased to accept returns within 30 days of the purchase date. All returned items must be in their original condition and packaging.

To begin your return process, please email us at:

Please note: Sale, clearance and personal use items, such as face masks, cannot be returned or exchanged for store credit.


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