Size and Colour of Moon - How to predict

Hi All

I understand the moon phases - but using normal observation, what makes the moon look larger and more orange some days than on others? Is it just an illusion?

Is there a way of predicting when one of those 'big orange' moons will appear (assuming a clear night of course)?

Thanks

It's reddish when it shines through lots of atmosphere because it's close to the horizon (Rayleigh scattering) or when it shines through dust in the atmosphere (Mie scattering). That's because both the atmosphere and dust scatters blue light more than red. That's why the sky is blue while sunsets, and low Moons, are red. You can make your own red moon at will by messing with the white balance, but that would be cheating.

The problem with shooting a low moon is that the atmosphere may distort or soften the image due to atmospheric turbulence.

The disk is about the same size all the time; it never varies by more than a few percent but looks much larger near the horizon. It's an optical illusion all the way but can be used to good photographic effect.

Thanks Rick - that helps

I'm scared to ask this next one, in case it's a really silly question...Is there a way knowing when (and where) it is about to pop up from the horizon or sink below it?

Bernoulli wrote in post #9072172
It's reddish when it shines through lots of atmosphere because it's close to the horizon (Rayleigh scattering) or when it shines through dust in the atmosphere (Mie scattering). That's because both the atmosphere and dust scatters blue light more than red. That's why the sky is blue while sunsets, and low Moons, are red. You can make your own red moon at will by messing with the white balance, but that would be cheating.

The problem with shooting a low moon is that the atmosphere may distort or soften the image due to atmospheric turbulence.

The disk is about the same size all the time; it never varies by more than a few percent but looks much larger near the horizon. It's an optical illusion all the way but can be used to good photographic effect.

Well said. One of my optometry professors tried to explain this to us, and I must say, you did a much better job than he did. I haven't heard the terms Mie and Rayleigh scattering in quite some time.

SAB_Click wrote in post #9072303
Thanks Rick - that helps

I'm scared to ask this next one, in case it's a really silly question...Is there a way knowing when (and where) it is about to pop up from the horizon or sink below it?

Download a free piece of planetarium software called Stellarium. When running the software, enter your location and then it will show what can be seen in the night sky from your viewing location.

As it is possible to fast forward it, or even run it backwards, you will be able to see what time the moon will rise and set for any given day.

HTH

Another way to predict it is to know that the full moon will rise during the sun setting. Each day thereafter, it will rise 45 minutes later. The full moon will set when the sun rises, and will set 45 minutes later each morning as well. Its not exact, but can give you an idea at least.

There's also this wonderful tool - The photographers Ephemeris. Tell it your location and it will show you the time and direction for sunrise, sunset, moonrise and moonset on a map. Very Handy.

Stevce.

SteveInNZ wrote in post #9073968
There's also this wonderful tool - The photographers Ephemeris. Tell it your location and it will show you the time and direction for sunrise, sunset, moonrise and moonset on a map. Very Handy.

Stevce.

I also like this program. I think it is excellent. You can pick out precisely where you want to shoot and it will show you the exact location/direction of the sun/moon rise/set. I was even able to locate a tree I've been wanting to shoot so it has quite a detailed map.

SteveInNZ wrote in post #9073968
There's also this wonderful tool - The photographers Ephemeris. Tell it your location and it will show you the time and direction for sunrise, sunset, moonrise and moonset on a map. Very Handy.

Stevce.

+100 Great little piece of software!

ETA: The map choices are great because one of them is a Topo. I like this 'cause it lets me see where the moon/sun will be in relation to specific land features like mountains and lakes.

To follow up a little on what Elizabeth said, there are some rules of thumb for when the moon is well-placed for photography. The moon, like the Sun, travels a changing path throughout the year. You want it as high in the sky as possible when you shoot. Here's a rough guide to the phase that's highest in the sky in a given lunation:

Spring: first quarter (waxing) right after sunset
Summer: new moon (not much good for photography)
Fall: last quarter (waning) just before sunrise
Winter: full moon around midnight

Here in northern Arkansas, the moon can get as high as about 7 degrees from zenith which, besides giving you a crick in the neck, minimizes atmospheric distortion. I use Starry Night for my planning, but there are lots of software packages that will do just fine, including the free ones mentioned in this thread.

I always recall this animation from Wikipedia's "moon" page.

For basic moon rise/mid/set I also use this.
http://www.usno.navy.m​il …ta-services/rs-one-day-us

gives data like this

mtbdudex wrote in post #9075074
For basic moon rise/mid/set I also use this.
http://www.usno.navy.m​il …ta-services/rs-one-day-us

gives data like this

<Snip>

Probably enough if your astronomically inclined but as I'm not, I like Photographers Ephemeris becuase it shows you azimuth in relation to geography in a much more easily interpretable form.

FlyingPhotog wrote in post #9075087
<Snip>

Probably enough if your astronomically inclined but as I'm not, I like Photographers Ephemeris becuase it shows you azimuth in relation to geography in a much more easily interpretable form.

That looks like a slick piece of software, my work has lockout on installing the actual exe file, so I'll have to try it at home.

I'm only astronomically inclined in that at nightime I take my 3 young kids outside and we look "up" and observe. They love helping me take shots of the moon.

Actually, they play nightime tag while I take the shots and make sure they don't trip on my tripod set-up. I've showed them the live view 10x and that looks cool on 3" LCD screen, "ooh's" and "ahh's" abound. Questions about the moon, how did it get there, moon craters, etc.

Building memories with them though to foster their scientific curiosity.

^^^ Most Excellent ^^^