Convert from vara [Spanish] to light year

Unit Definition (vara [Spanish])
Vara is an old Spanish and Portuguese unit of length. Varas are a surveying unit that appears in many deeds in the southern United States, and varas were also used in many parts of Latin America. It varied in size at various times and places; the Spanish unit was set at about 835.9 mm in 1801. At some time value of 33 in (838 mm) was adopted in California, and 33 1/3 inches (847 mm) in Texas.

Unit Definition (light year)
The distance that light, moving at a constant speed of 300,000 km/s, travels in one year. One light year is about 10 trillion kilometers.