Orosi Valley  

Sundial: 761
State/Province:  Cartago Country:  Costa Rica
Dial Type:  Obelisk or Vertical Gnomon Condition:  Excellent
  Latitude and Longitude: 9° 46.921' N  83° 50.058' W
Location: Access: This is a private dial. See below for access details.
  • Private residence, Pondorosi Lodge, built on a former coffee plantation on Gavilan Hills overlooking Orosi Valley, a historical region of Cartago. An English-speaking guide José-Alfredo Jiménez provides a coffee tour and can include the dial in the itinerary by request. Contact at 011-506-8377-6745 or 4321jose@gmail.com. He offers transportation services as well.
  • A 25 foot long point-in-space or nodus dial. The horizontal dial face is cuartilla (crushed stone). The 8 AM - 4 PM hour lines are red adoquines (bricks) and the noon hour line is lodged between gray adoquines. The dial equinox line is a row of gray adoquines. Solstices are identified by the curve formed by the tips of the hour lines. The gnomon atop a 1.8 m high vertical rod is a 21 cm diameter sphere, hand carved out of gabbro, a rock formed from molten magma. It is a replica of bolas de piedra (stone balls) created a thousand years ago by the local Diquis indigenous people and discovered in 1930.

    As of 2020, this is the southernmost sundial in the NASS registry. It is curious that so few dials are built in the intra-tropical regions because at these latitudes, dials of this type can be easily designed using free software and inexpensively constructed. In addition to the time of day, the dial shows the change of seasons passing the equinoxes and the limits of the solstices. The design also shows zenith days when the sun culminates directly overhead on April 14 and August 27, casting only a perfectly round shadow of the bola at local solar noon. This only occurs in areas between the Tropic of Cancer and Tropic of Capricorn.

    The dial changed a bit in 2021 as explained by Mark Jensen: "The area around the sundial was already somewhat cluttered and then my wife wanted to put in a concrete walking path around the perimeter of our hilltop. The route she suggested would chop off part of the hour lines. Can you imagine? Even if the bricks were retained it would look slapdash. It meant chopping down her favorite butterfly and hummingbird attracting bushes, but she agreed with my compromise to have the path go straight down the equinox line. It may actually look per-conceived and multi-purposed. The workers just finished the concrete job. This is the rainy season, but mornings are usually clear, so they start the concrete mixing machine at 6am."

    Mark continues,"I think we've got it....I started reading about sundials, came across Shadows software, corresponded with John Carmichael, who kept telling me was too busy but still answered my questions. Shadows was designed for tinier dials and I had to extrapolate the data points for the equinox and hour lines, but was uncertain about the height of the gnomon until John ran the data and confirmed it. He was the one who suggested I register with [NASS].

    "My biggest problem was determining true north. A compass wasn't accurate enough and at our latitude Polaris is hidden behind a volcano, though I could sometimes see the pointers. I determined from Google maps how much our house was angled vis a vis north and mapped it out...." You can see his results in the photo enclosed.

General Information:
  • Owner: Mark Jensen
  • Designer: Mark Jensen
  • Builder: Crew Chief Norlan Ruiz, Germán Chavarría, Alí Chamber
  • Construction Date: March 2012
References: Web Links:
  • Orosi Valley is considered by guidebooks to be the most beautiful valley in Costa Rica.

Last Revised: 2021-07-06 15:28