Can a New Moon look like a Lunar Eclipse temporarily??

when i went outside tonight, i noticed that the sliver of the new moon looked awfully thin. i went back inside, and came out again around a half-hour later, and the sliver was even thinner! while having a smoke with my brother-in-law on the porch, we watched the sliver disappear completely in about 5-10 minutes! we were practically convinced that it was a lunar eclipse, but we were wondering how it could be one if the sun just set hours earlier, because they're obviously created by the Earth's shadow on the moon.

is it possible for a new moon to resemble a total lunar eclipse, if only for a few minutes?

we were waiting for the top side of the moon to reemerge from behind the shadow, for an hour, but the moon went out of sight beyond the horizon. it was still well above the horizon, though, when the moon was completely covered by the shadow. what would cause the visible part of the new moon to completely disappear like a total lunar eclipse??

all this happened around 1-2 hours before the moon set behind the treeline... i've never seen anything like it... it seemed as if there was something giant covering the moon!

Originally posted by adrenochrome
is it possible for a new moon to resemble a total lunar eclipse, if only for a few minutes?

Basically, yes it is.

You were lucky to catch the moon when it was so 'young', but yes, it looks just like thin sliver, and over time it can be seen to resemble an eclipse as you say.

I think that this is effectively just the moon 'eclipsing itself', but I'm sure some of our members who are more knowledgeable about the moon than myself will shed more light on the matter, if you'll excuse the pun

A new moon is essentially when the moon is casting its own shadow on itself and occurs when the moon is between the Sun and the Earth. Not to be confused with a Solar eclipse. An Eclipse always occurs at the time of a New Moon, but not vice versa.

A lunar eclipse occurs when the Earth's shadow falls upon the Moon and always occurs at the time of a Full Moon.

The appearance of a lunar eclipse is very different from the New Moon. There is usually an orangey-red cast on the Moon and (to me) the Moon really takes on a 3D, spherical appearance rather that the flat disc it appears to be with a normal Full Moon. The full face of the Moon remains visible. It also occurs at a much faster rate than the change in phase.

[edit on 2/26/2009 by Phage]

thanks for the replies, but it appeared as if the moon's own shadow moved to "black-out" the entire moon. again, within a matter of minutes, the shadow moved downwards to cover the tiny sliver of the new moon - we watched it "eclipse" right before our eyes!!

also, and i hate to admit it, but my brother-in-law just might be smarter than me (if only slightly ), and he mentioned that it was an eclipse before i did... i wish i had a camera to prove this, but you'll just have to take my word that it looked like a total lunar eclipse!

i went on "Stellarium" shortly after this event, and it showed that the sun was well below the horizon, but it was still towards the west, going along the same path as the moon. if you can, go on "Stellarium" and erase the ground/horizon, and see where the sun and moon are from 6:30-9pm EST. now, view the moon and imagine if the large shadow on top moved downwards to cover up the sliver on the bottom, so the moon completely "disappears". that's what happened!

we both swore that it was a total lunar eclipse, but later realized that it was just a new moon...

reply to post by adrenochrome


I understand what you're saying. When I said an actual eclipse is faster I meant that it covers the entire Full Moon in an hour or so. It takes two weeks to go from a Full Moon to a New Moon.

I haven't caught the exact moment the Moon has turned new like you did and I didn't realize the last bit of the change would be perceptible. It makes sense that it is. I'm going to make an effort to see it.

reply to post by adrenochrome

The new moon was on Tuesday (Feb. 24th), and last night (Thursday, Feb 26) was a "young moon". By definition a young moon will only get more visible as the moon cycle goes on. So I'm not to sure if it is really possible that you saw the sliver of moon "disappear" due to the shadow on the moon getting larger -- or even if it is possible for that shadow to be noticeably different in 10 minutes time.

A young moon can only ever be seen for an hour or two after sunset, and always low on the western horizon. I suspect that possibly as the moon was setting and you were viewing it through more of the Earth's atmosphere, the moon's light became more obscured by dust in the atmosphere as the moon set -- just like the sun's light dims as it gets closer to sunset.

In the case of a sunset, the Sun's light itself is obviously not changing -- just the amount of that light that we can see through the additional amount of atmosphere we are viewing it through. I think the same thing happened for you last night -- the Moon didn't noticeably change, but the amount of moonlight that reached your eye through the additional atmosphere DID change.


[edit on 2/27/2009 by Soylent Green Is People]

reply to post by Soylent Green Is People


yes, technically the moon should become more visible according to the stage it's in, because it's on its way to becoming a quarter-moon within the next week. but the shadow got larger, and the moon disappeared, so i still can't explain why it appeared to resemble a total eclipse... i don't think it was the atmosphere, because i could still faintly see the silhouette of the entire moon under its own shadow; the moon didn't disappear beyond the horizon until about an hour later...

the next time there's a new moon, i'm going to be sure to view it as it's setting behind the horizon to see if it "eclipses" again...