Solstices and equinoxes are also celebrated. Inca astronomers understood equinoxes, solstices and zenith passages, along with the Venus cycle. This causes seasons which are dependent on equinoxes and solstices. It is generally brighter near solstices and dimmer at equinoxes. Their starts are related to equinoxes and solstices. The Maya were aware of the solstices and equinoxes. There are two solstices and two equinoxes in a tropical year. Other holidays celebrated by members include the two solstices, the two equinoxes, and Yule. He calculated the duration of the year and the timings of the equinoxes and solstices. The solstices and equinoxes divide the year up into four approximately equal parts. The solstices, together with the equinoxes, are connected with the seasons. The Sun moves eastward on the analemma near the solstices. The Gregorian calendar is currently accurately lining up with astronomical events such as solstices. The concept of the solstices was embedded in ancient Greek celestial navigation. These do not occur on the dates of the solstices.