24
$\begingroup$

The title basically says it all. As seen from the Earth, is it possible for the Moon to eclipse Venus (or any other planet) or are the orbits inclined such that this never happens?

If such an eclipse is possible, is it a frequent or infrequent event? How would I find out when the next one occurs?

Improve this question
$\endgroup$
8
  • 6
    $\begingroup$ I'm pretty sure that the answer is yes. I'm guessing that people don't pay it any attention because it isn't visually interesting the way that lunar and solar eclipses are. $\endgroup$
    – Donald.McLean
    Aug 23, 2018 at 14:52
  • 2
    $\begingroup$ apod.nasa.gov/apod/ap980513.html is a picture of such an occultation which also happens to be a double occultation with Jupiter. solarsystem.nasa.gov/resources/472/lunar-occultation-of-venus is another. skyandtelescope.com/observing/… is an article on an occultation. With a little work, you should be able to find a list of occultations (I couldn't but I didn't search very long). $\endgroup$
    – user21
    Aug 23, 2018 at 15:14
  • 5
    $\begingroup$ @barrycarter, write answers! $\endgroup$
    – Mike G
    Aug 23, 2018 at 15:55
  • 4
    $\begingroup$ Note that occultation is a bit different to an eclipse, since in occultation the Moon merely blocks our view of the occulted body, whereas in an eclipse a shadow is cast: the Earth's shadow on the Moon in a lunar eclipse, and the Moon's shadow on the Earth in a solar eclipse. $\endgroup$
    – PM 2Ring
    Aug 23, 2018 at 22:42
  • 4
    $\begingroup$ @CannonFodder It's a useful distinction because the shadow in an eclipse is a fundamental feature of the phenomenon. Whereas with an occultation the occulted body is not obscured by a shadow cast by the occulting body. E.g. if a Full Moon occults Jupiter, their shadow cones are pointing away from Earth, and the Moon's shadow certainly doesn't create a solar eclipse on Jupiter. But I guess if it's aligned correctly, and you had a good telescope, you could see our Moon (and the Earth) transiting the Sun from a Jovian orbit. $\endgroup$
    – PM 2Ring
    Aug 24, 2018 at 21:35

2 Answers 2

Reset to default
35
$\begingroup$

As @Donald.McLean said in comments, the answer is yes, the Moon can and does occult the other planets in the Solar System. When something apparently big (like the Moon) passes in front of something apparently small (another planet) it's called an occultation. (I say apparently because from our perspective the Moon appears larger than the planets.)

The planets lie* in the ecliptic plane whereas the Moon's orbit is inclined at about 5° to the ecliptic plane, so the Moon crosses the ecliptic plane twice each orbit, so it's not as frequent as it would be if the Moon's orbit were in the ecliptic plane.

Occultations of the planets by the Moon can be found here. There is also software (Occult) that you can use to generate your own predictions.

* Although the planets are said to lie in the ecliptic plane, this is a generalisation - they actually have orbits that are within a few degrees of the ecliptic "plane".

Improve this answer
$\endgroup$
7
  • 3
    $\begingroup$ It's pretty common to use "big" to indicate angular extent rather than physical size, but props for being explicit here. $\endgroup$
    – Carl Witthoft
    Aug 23, 2018 at 15:34
  • 2
    $\begingroup$ "Occult", from the Latin occultus: clandestine, hidden, secret. $\endgroup$
    – RonJohn
    Aug 23, 2018 at 23:38
  • 1
    $\begingroup$ "The planets lie in the ecliptic plane whereas the Moon's orbit is inclined at about 5° to the ecliptic plane" The planets also have inclined orbits, Venus for example has 3.4° inclination relative to the ecliptic plane. $\endgroup$
    – JiK
    Aug 24, 2018 at 12:38
  • 2
    $\begingroup$ @JiK Yes, I may have oversimplified a bit. $\endgroup$
    – Mick
    Aug 24, 2018 at 12:44
  • $\begingroup$ Given the moon has an angular diameter of 0.5°, about 10% of it's orbital inclination, passing the elliptic plane involves an extended period of potential occlusion each half orbit. $\endgroup$
    – TemporalWolf
    Aug 24, 2018 at 21:13
13
$\begingroup$

Yes, such events are called occultations. The Moon can occult anything within about 5 degrees of the ecliptic. The visibility of any lunar occultation is limited to a path as wide as the Moon is.

This EarthSky article discusses a series of lunar occultations of planets in September 2017, including Venus as seen from Australia. The article includes a photo of a February 2014 occultation of Venus and an excerpt of Guy Ottewell's lunar occultation charts for 2017.

The Sky & Telescope article which barrycarter found describes a lunar occultation of Venus visible from North America in December 2015 and includes a photo of an April 2009 occultation of Venus.

Improve this answer
$\endgroup$
2
  • $\begingroup$ Thanks for this. The key word I was missing was occultation. With that, Google searches become much more informative! $\endgroup$
    – CatchAsCatchCan
    Aug 23, 2018 at 21:30
  • 1
    $\begingroup$ calsky.com/… gives lunar occultations for the next 2 years or so. $\endgroup$
    – user21
    Aug 26, 2018 at 19:59

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .