## Sun Rise Calculations

Knowing the earth rotation and revolution correctly makes it possible to calculate the time and angle of sunrise precisely for any location on Earth. We should be aware that there … Read More

## Sun Distance

Sun distance from earth ranges from 147 million kms to 152 Million kms. Sun distance depends on the time of the year and it is less in winter and more … Read More

## Equation of Time

Equation of time is the difference between apparent solar time and mean solar time. EOT = apparent solar time – mean solar time Wikipedia defines EOT by the follwoing: The … Read More

## Sun Right Ascension

Wikipedia defines Right ascension (RA) as the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle … Read More

## Proportion Test – Example

In the previous post, we explained how to calculate P-value and thus perform hypothesis testing for categorical data. In this post we will give an example. A study was performed … Read More

## Proportion Test

The parameter of interest when we deal with categorical data is the sample proportion. An example of a sample proportion could be the proportion of people that are use cannabis. … Read More

## Null Hypothesis

Null hypothesis is effectively stating the default situation. It is as you said there is nothing going on. When some one puts forward a claim the null hypothesis is that … Read More

## Islamic Crescent

Moslems Must Observe the apparent movement of the sun across the sky in order to performs prayers. There is no consensus on the times of the prayers among different Moslem … Read More

## Directions On Map

The direction between any two places on Earth can be calculated using the spherical trigonometry. We can use the following equation to do that Direction Angle =tan-1 (sin(longitude2 – longitude1)/cos(latitude1)*tan(latitude2)-sin(latitude1)*cos(longitude2-longitude1)) … Read More

## Calculating Sun Declination

Declination of the sun is the angle between the equator and a line drawn from Earth to Sun center to center. The declination angle varies seasonally due to 2 factors … Read More