On the first Wednesday, God created lights in the heavens: the sun, moon, and stars. One of the primary purposes was to mark the passage of time. These lights were for "signs and for seasons and for days and years" (Genesis 1:14). In past generations, telling time by the stars was an essential part of life. In our modern society, where wristwatches and cell phones are everywhere, this has become a lost art. But it is really pretty easy to do. You can even roughly estimate the time by eye, as long as you don't need high precision.
The sun is the primary object we use to tell time. The time is roughly noon when the sun reaches its highest point in the sky. The sun will appear directly south of overhead if you live north of the tropics. (The time can be a bit off from noon depending on where you live within your time zone. Also, you need to add one hour during daylight savings time. But this method works well to make a rough estimate.)
Telling time by the stars has many similarities (and challenges). Like the sun, stars rise in the east and set in the west. So if you see a star rise due east, it will reach its highest point in the sky six hours later and will set six hours after that. A good example to look for is Orion, visible during mid-winter. During early January, this constellation rises due east around 6:00 p.m. and sinks to the west at 6:00 a.m.
[Read the rest of the article at Answers in Genesis.]