Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: clueless on 14/07/2013 20:36:34

Title: Is the Moon visible in the daytime as well as at night?
Post by: clueless on 14/07/2013 20:36:34

I've seen the Moon during night only. Can the Moon be seen during daylight and for how long? Thanks.

Title: Re: question about the Moon
Post by: SeanB on 14/07/2013 21:01:33

All day long for sure, I often see it in the morning and evening as I walk, as the road runs East west.

Title: Re: question about the Moon
Post by: evan_au on 15/07/2013 12:31:37

The moon is up in daylight just as much as it is up at nighttime.  This is because of it's orbit relative to the Earth's rotation.
In fact, if you pick a random time of the day or night, there is a 50% chance that the Moon will be above the horizon (assuming your house isn't surrounded by tall mountains or forests...)

But the moon is much easier to see at night because it is usually the biggest and brightest object in the night sky.
In the daytime, it is really quite dim compared to the Sun, so you have to actually look for it.

Look at a Moon Phases calendar, eg: http://www.moonconnection.com/moon_phases_calendar.phtml
On 16th July 2013, it will be a half-moon. This means there is a 90 degree angle between the Sun-Moon line and the Earth-Moon line.
This means that the Moon is visible about half of the time in Earth's day, and half in Earth's night.
You should be able to see it easily from about 3pm to 9pm (if you are in high Northern latitudes, this will be visible against a bright Summer sky).

The only time you can't see it at all is when it is right near the Sun (which happened on the 9th July this month), and it is totally lost in the glare of the Sun - not helped by the fact that the Sun is illuminating the far side of the Moon, so we are trying to spot a dark body close to the bright Sun.

Title: Re: question about the Moon
Post by: evan_au on 20/07/2013 14:01:34

I took this photo with my camera this afternoon - the Moon in the sky during daytime, bordered by clouds and leaves on a gum tree.
The Moon does not stand out well against the light blue sky, and it is no brighter than a daytime cloud, so you have to look for it.

Title: Re: question about the Moon
Post by: RD on 20/07/2013 16:07:17

Quote from: evan_au on 20/07/2013 14:01:34

I took this photo with my camera this afternoon - the Moon in the sky during daytime ...

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It's the wrong way up ;¬)

 [ Invalid Attachment ]  (http://en.wikipedia.org/wiki/Moon)

Title: Re: question about the Moon
Post by: CliffordK on 20/07/2013 18:02:43

GREAT PHOTO

Quote from: RD on 20/07/2013 16:07:17

It's the wrong way up ;¬)

With the sun above the horizon, the "sliver" should in fact be in the lower direction.

And the And the Mare Imbrium, Mare Frigoris, and Oceanus Procellarum are all in the correct orientation.

Title: Re: question about the Moon
Post by: RD on 20/07/2013 20:28:10

Quote from: CliffordK on 20/07/2013 18:02:43

... the Mare Imbrium, Mare Frigoris, and Oceanus Procellarum are all in the correct orientation.

for those in Australia (http://www.thenakedscientists.com/forum/index.php?action=profile;u=26889).

Title: Re: question about the Moon
Post by: evan_au on 20/07/2013 23:46:08

It was taken in Sydney, Australia, about 4:30pm, so the image will be inverted compared to someone observing from the Northern hemisphere.
...As I child, I heard people talking about "the man in the moon"; to me it looked more like a rabbit (two long ears). 
In this case I used a digital camera; you can see which way was "down" by the drooping leaves on the gum tree.

Astronomical telescopes traditionally leave the image inverted to save passing the image through yet another lens (which would absorb a bit more light).
If you use a right-angle adapter on the telescope eyepiece, that also reverses the image.
So on a telescope, you could end up with up/down/left/right reversals, which makes it trickier to aim the telescope!