FAQs
1.Question: What does the "Birth of New Moon" mean, and what is conjunction?
Answer: Conjunction or birth of new moon is the same thing. "A conjunction occurs when the Moon passes between the Earth and the Sun; but because the Moon usually passes north or south of the Earth-Sun line, it specifically occurs when the Earth-Sun-Moon plane is perpendicular to the plane of Earth's orbit around the sun." This moment is called "New Moon Birth" or conjunction. At this moment the sunlight falling on the moon cannot come to the earth. In other words new moon is "No Moon". No one can see this "New Moon" even by most powerful telescopes.
2.Question: Is it possible to see the astronomical new moon (invisible moon) using telescope?
Answer: The astronomical new moon happens when the moon comes between earth and sun, and that new moon cannot be seen by the most sophisticated telescopes. It is called invisible moon, becuase its lighted portion is towards the sun and dark portion is towards the earth.
3.Question: After the Moon Birth, how much time is required for people to sight the New Moon?
Answer: Time passed after New Moon Birth is called the age of the moon. Sighting is possible at different age in different months. So, age cannot be a criterion for sighting. Why is it so? Because, the orbit of the moon is elliptical and in its orbit, the moon moves faster when it is closer to the earth, and slower when it is farther from earth. When it moves faster, the moon becomes visible at smaller age (like 17 hours), and when it moves slower, it becomes visible at larger age (like 23 hours). The main factor that makes the moon visible is the angle between moon-earth-sun. When this angle becomes about 9 degrees, the moon starts to be visible. How much time it takes to get this angle depends upon the speed of the moon in its orbit.
4.Question: Why is the moon sometimes big and orange and sometimes small and white?
Answer: The moon travels in an orbit around the earth in an oval path, so its distance from earth varies. When it is closest to the earth it looks bigger. The colors variation is due to variation in the pressure, temperature, and humidity in the atmosphere, which goves more pronounced affect for a viewer when the moon is near the horizon.
5.Question: What is "New Moon Birth" and are there any differences in calculating the timing of the new moon birth by different people or different observatories?
Answer: The definition of "New Moon Birth" also known as "Astronomical New Moon" or "Conjunction" is the moment of time when the earth, sun and moon are in the same plane. In scientific terms, the Birth of New Moon is the time when sun's ecliptic longitude and moon's ecliptic longitude are the same with reference to the center of the earth. This could happen at any moment from 0:00 hours to 23:59 hours Greenwich Mean Time (Universal Time), and at that moment the moon is dark as seen from the earth. So, you can also think of a "New Moon" as "Dark Moon" or "Invisible Moon". Some people calculate the ecliptic longitude of the moon and sun from a specific location on the surface of the earth. This may be called as topocentric new moon or topocentric conjunction. There are different algorithms to calculate astronomical new moon (conjunction) depending upon the accuracy desired. Some are more accurate than others. Less elaborate and sufficiently accurate formulae can calculate the birth of new moon with an error up to +2 or -2 minutes, and for most practical purposes this accuracy is sufficient. So, calculations of conjunction by different algorithms may disagree slightly.
6.Question: I've been told that we always see the same side of the moon. There is always a hidden side that we can never see. Is this true? If so, why is it?
Answer: Yes, it is true. The moon rotates around its own axis in about the same time as it takes to circle the earth. These two motions cause the same side of the moon turned towards earth in general. Due to some variations in these motions and some other minor phenomena (liberation and wobbling), the people from earth can only see about 59% of the moon's surface at different times and place, which is a little more than (50% of the lunar surface) one side of the moon as seen from earth.
7.Question: The moon is the closest object to the Earth, yet we do not see it for some part of the month. Where does it go? Is it because of light or darkness?
Answer: The moon is totally dark object; it does not have any light of its own. It merely reflects sunlight falling upon it. When sun is on the opposite side of the moon looking from earth, the side of the moon facing earth is completely dark, and we can not see this moon for about 36 hour every month. On all other days, the moon is at a different angle from the sun and we see different phases of the moon. It rises and sets because of the curvature of the earth as earth revolves around its own axis.
8.Question: Is it possible for the dark moon (unilluminated) to be above the horizon after sunset before it is born? When does this happen?
Answer: Yes, it is possible. The moon quite often sets 5 to 25 minutes after sunset when new moon is not born yet, that is its age is negative. The moon can set several minutes after sunset even when there are 10 hours to go before the new moon birth. It could happen in different places on the globe in different months.
Setting of sun and moon are the functions of the curvature of the earth from a particular location. New Moon is one instant of time when one spot on earth faces the line between sun and moon. At that moment other places on earth have sunrising, sun overhead, or even midnight. Same way moon can be at different situations. Moon setting after sunset is just its position relative to sun and that position is different at different times and at different latitudes in Northern and Southern hemisphere.
Reference: www.moonsighting.com