This is the Marsdial that is on board the Spirit and Opportunity as well as the Curiosity rover missions. It functions both as a mars sundial and provides a very accurate way to calibrate the color camera's on both missions. I modeled this from available official public technical documents and photos. Although the result is close, there are likely some dimensions that are off a little bit from the original flight model that went to Mars. :)I printed this with PLA with the extruder at 200 degrees C, bed 55 degrees C, 0.1 mm layer height, 70 percent infill rectangular pattern, with multiple bottom and top surface layers.The sundial gnomon is split for printing. Print these objects side by side. There is an alignment pin on the bottom half with a hole in the top half. Both are 3 mm in diameter in the CAD model, however in my case after printing, the hole in the upper half may need to be cleaned out or enlarged to fit the pin from the lower half.