Sidereal timeSidereal time ("sidereal" pronounced saɪˈdɪəriəl,_sə- ) is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night sky. Sidereal time is a "time scale that is based on Earth's rate of rotation measured relative to the fixed stars". Viewed from the same location, a star seen at one position in the sky will be seen at the same position on another night at the same time of day (or night), if the day is defined as a sidereal day (also known as the sidereal rotation period).
SnowshoeSnowshoes are specialized outdoor gear for walking over snow. Their large footprint spreads the user's weight out and allows them to travel largely on top of rather than through snow. Adjustable bindings attach them to appropriate winter footwear. Traditional snowshoes have a hardwood frame filled in with rawhide latticework. Modern snowshoes are made of lightweight metal, plastic, and other synthetic materials. In the past, snowshoes were essential equipment for anyone dependent on travel in deep and frequent snowfall, such as fur trappers.
