# Why don't we see solar and lunar eclipses often?

Since we see the new moon at least once in a month when the Moon gets in between of the Sun and the Moon at the night and as far as I know if this happens during the day, you'll get to see a solar eclipse. Why don't we get to see this often or in the day?

Does it mean that in some part of world there's a solar eclipse when we are seeing a new moon? I'm looking for a diagram or interactive way to understand this if possible as I'm not a native English speaker, but I'll try my best to do so.

-
Welcome to Physics Stack Exchange! If you're curious about the solar system, you might have fun playing around at astronomy.stackexchange.com too. –  AlanSE Apr 29 '12 at 15:41
@AlanSE: while true, it's of limited value to point people to Astronomy because it's closing this week and we may be absorbing their questions. –  David Z Apr 29 '12 at 18:20
Though the answer below answers the question but I'm also desperately looking for an interactive set of models of sun, moon, and earth (possibly some sort of java applet) where I can play with them to get some practical knowledge. If anyone finds or knows please let me know. –  user102421 Apr 30 '12 at 5:30
–  Qmechanic May 13 '12 at 21:01
Added images. Review it. –  Mr.ØØ7 Apr 26 '13 at 15:08
show 1 more comment

The thing is, the Moon's orbital plane is slightly tilted (about 5$^\circ$) with respect to Earth's which means from the Earth's perspective that the Moon's motion oscillates around the Sun's trajectory. On most new moons, then, the Moon is either north or south of the Sun and we don't see an eclipse.

For eclipses to happen, new and full moons must occur when the Moon crosses the Ecliptic. Equivalently, the intersection of the Moon and Earth orbital planes have to align with both the Sun-Earth and the Earth-Moon directions. No wonder they don't happen that often!

Edit: I don't know any good 3D simulator, but I found My Solar System (which I got from Mike's answer to this question) good fun.

-

No, there is not a solar eclipse whenever we see a new moon. The reason we do not have a solar eclipse at every new moon is mostly due to the angle of Earth's axis (and by extension, the Moon's orbital plane) to the Earth-Sun line. See the picture below for a visual explanation. In the picture, the Sun is to the left. The upper image shows the orbit of the Moon during winter, the lower image shows the possible regions affected by the Moon at different times of the year.

At different times of the year, the Moon's orbit (which is more or less right above the equator) is tilted with respect to a line between the Sun and Earth. Only in the right conditions will you see a solar or lunar eclipse.
Additionally, it is worth noting that (and this is strictly technical) no New Moon that is not a solar eclipse (i.e. the observer is in the umbra) is a "full" New Moon. However, the sliver of light that is "visible" from Earth for these situations is too narrow and/or dim to be discerned by the human eye.

Image taken from http://www.uwgb.edu/dutchs/AstronNotes/HowSolSysWorks.HTM

For more information, see this similar question: Why is a new moon not the same as a solar eclipse?

-
Well, but still when you look at 3D images I have posted, you can see that if there is no solar eclipse, there should be visible part of the Moon at day. I am explaining this there: dropbox.com/s/kpvek8speg2wu9e/simLJ.png Or is it wrong? –  Firzen Apr 26 '13 at 16:04
@Firzen: The new moon is visible during the day, provided you can block out the glare from the sun. This is most easy to see just after sunset or just before sunrise. –  Mike Dunlavey Apr 26 '13 at 16:31
@Firzen Not really mentioned in this answer but sort-of visible in the images is that no new moon is a *perfect* new moon unless it is viewed from the umbra. The sliver of light is just so small that we can't discern it. –  Izkata Apr 26 '13 at 18:16
Yes, thank you. I'll add that in. –  Jim Apr 26 '13 at 19:11