We don't get a lunar eclipse (earth obscuring the sun to the moon) or a solar eclipse (moon obscuring the sun to earth) every month, since the alignment of the sun, moon and Earth is not exact enough. The moon sun and earth are not on the exact same plane, so most of the time when the moon passes in front of the sun, it is either too low or too high to cause a solar eclipse. Similar story with the moon passing behind the Earth for a lunar Eclipse.
When the conditions are right, a lunar eclipse can happen in ANY month, but only at the time of Full Moon.
one month
A lunar eclipse can occur multiple times a year, but the frequency can vary. On average, there are about two to four lunar eclipses each year. Lunar eclipses can be partial, total, or penumbral, with total eclipses being less common.
because all the moon phases have to occur before the full moon and the new moon
A solar and lunar eclipse do not occur every month because the orbits of the Earth and the Moon are tilted relative to each other by about 5 degrees. Eclipses can only happen when the Sun, Earth, and Moon align closely, which occurs during specific times known as eclipse seasons, roughly every six months. During these periods, if the alignment is right, a solar eclipse (when the Moon covers the Sun) or a lunar eclipse (when the Earth casts a shadow on the Moon) can take place. Thus, while eclipses can happen multiple times a year, they do not occur every month.
Because it's a very rare occasion
They never do. They're always at least a month apart, and far more often several months apart.
When the conditions are right, a lunar eclipse can happen in ANY month, but only at the time of Full Moon.
A solar eclipse doesn't occur every 28 days because the moon's orbit is tilted compared to the earths.
one month
The first of a lunar month.
A lunar eclipse doesn't happen every month because the Moon's orbit is tilted relative to Earth's orbit around the Sun. This means that most of the time, the Moon passes above or below Earth's shadow, so a lunar eclipse only occurs when the alignment is just right.
Lunar eclipses can happen a maximum of twice per year, and only at the time of the full moon. Sometimes the alignment is just right, and we get a total lunar eclipse. If the alignment isn't exact, we might get a partial or a penumbral eclipse instead of a total eclipse.
why does a lunar or solar eclipse not occurs every month?
Its December 31st 2009, there is no lunar eclipse for me. But there is a Blue Moon. 2nd full moon of the month... and It is big and bright tonight.
Because the moon does not orbit in the same plane as the Earth-Sol plane. Note that they will only form a straight line twice per year, and if the three bodies are not lined up there will be no eclipse.
Lunar eclipses are usually either one month apart or five months apart.