Maybe you have found a IDX file on your computer and wondering what it's for? Windows might tell you that you can't open it, or in the worst case, you might encounter a IDX file related error message. Before you can open a IDX file, you'll need to figure out what kind of file the IDX file extension refers to. Tip: Incorrect IDX file association errors can be a symptom of other underlying issues within your Windows operating system.
There are two equinoxes every year â in March and September â when the Sun shines directly on the equator and the length of night and day are nearly equal. The Earth during the equinox. (Not to scale)On the equinox the Earth's axis is perpendicular to the Sun's rays.
1 Astronomically speaking, the March equinox occurs when the Sun crosses the celestial equator on its way north along the ecliptic. 2  In the Northern Hemisphere, the March equinox is known as the vernal, or spring, equinox, and marks the start of the spring season.