which two things are needed to determine a standard candle distance from earth
Cosmic distance ladder Almost all astronomical objects used as physical distance indicators belong to a class that has a known brightness. By comparing this known luminosity to an object's observed brightness, the distance to the object can be computed using the inverse-square law. These objects of known brightness are termed standard candles.
Daytime At middle latitudes, far from both the Equator and the poles, variations in the length of daytime are moderate. In the higher middle latitudes where Montreal, Paris and Ushuaia are located, the difference in the length of the day from summer to winter can be very noticeable: the sky may still be lit at 10 pm in summer, but may be dark at 5 pm in winter. In the lower middle latitudes where Southern California, Egypt and South Africa are located, the seasonal difference is smaller, but still results in approximately 4 hours difference in daylight between the winter and summer solstices. The difference becomes less pronounced the closer one gets to the equator. An approximation to the monthly change can be obtained from the rule of 12ths. With 4 hours change over the six months from winter to summer the day lengthens by about 4*1/12 of an hour (20 mins) in the first month, 4*2/12 (40 mins) in the second month, 4*3/12 (1 hr) in the third month, then 1 hr, 40 mins and 20 mins in the fourth, fifth and six months.