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Saint Fool
02-18-2007, 11:13 PM
This may be the dumbest question ever asked on this board .... but S'Fools rush in ,etc.

When the moon is dark, is it still possible to see it in the night sky? If the observer knows where it should be? Would it be able to be seen as a dark circle against an even darker night sky? Or - improbablity of improbabilities - a dark circle backdropped against the Milky Way?

Or can anyone recommend an astronomical site where I could ask this question without too much snickering and giggling?

Plot bunnies ... got to love them.

alleycat
02-18-2007, 11:41 PM
The short answer is yes, it can be "seen".

Adagio
02-19-2007, 12:34 AM
http://en.wikipedia.org/wiki/Lunar_phase

It might help.

Adagio

alleycat
02-19-2007, 02:57 AM
This is not quite what you asked about, but here's an interesting chart on the visibility of the moon from various location on the earth on a certain day. Click the link at the bottom for a full description of how to read the chart.

http://moonsighting.com/

Histry Nerd
02-19-2007, 07:19 PM
A new moon actually rises during the day, so it would be difficult to see it in the night sky. If it is present during hours of darkness (more likely during the winter), it would be low to the horizon, probably not high enough to be silhouetted against the Milky Way.

You can go to this page (http://aa.usno.navy.mil/data/docs/RS_OneYear.html)to download a table of sun and/or moon data for an entire year from just about anywhere in the world. It lists moonrise/moonset, but not phase. You should be able to get the phases pretty easily from somewhere else and cross-check them with the moonrise and moonset times.

HN

Saint Fool
02-20-2007, 03:29 AM
Thanks for the suggestions and help. Off to bookmark and figure out where the moon will be on the 18th of March.

benbradley
02-20-2007, 06:05 AM
This may be the dumbest question ever asked on this board .... but S'Fools rush in ,etc.

When the moon is dark, is it still possible to see it in the night sky? If the observer knows where it should be? Would it be able to be seen as a dark circle against an even darker night sky? Or - improbablity of improbabilities - a dark circle backdropped against the Milky Way?

A New Moon isn't really dark, since the "dark" side is facing a "Full Earth". Sunlight shines on the Earth (which appears about four times the diamater in the Moon's sky as the Moon appears to us on Earth), which then shines on the New Moon. This isn't bright, but it's brighter than the Milky Way (which you can't see at all near major cities due to the light pollution). It's pretty plainly visible when the moon is in a small crescent phase and during night (shortly before Sunrise or after Sunset, since the Sun is not that far away in the sky from a New Moon). You can see this as a "greyish full moon" with a sliver of bright Moon where the Sunlight is shining on it.

Here's an explanation
http://en.wikipedia.org/wiki/Earthshine
Here's a nice pic:
http://www.allthesky.com/various/earthshine.html

I think it would be very unlikely for the Moon to be seen in front of the Milky Way at any phase. The New Moon is near the horizon, where the Milky Way is pretty much invisible. At other phases, the Moon is so bright in the sky it makes the tenouos Milky Way impossible to see. Most astronomers time their observations to when the Moon is NOT above the horizon, because it is usually so bright it causes light pollution (just like being in/near a big city), making it impossible to see very faint objects.

alleycat
02-20-2007, 05:26 PM
Another site that might be of some interest: http://www.wonderquest.com/NewMoon.htm

By the way, there used to be all sort of freeware astronomy software you could download. You just had to key in your location and time and it would show almost each large object in the sky. It's really cool if you're into astronomy. I haven't used one for a long time so I don't what's available now.

C.bronco
02-20-2007, 05:58 PM
A new moon actually rises during the day, so it would be difficult to see it in the night sky. If it is present during hours of darkness (more likely during the winter), it would be low to the horizon, probably not high enough to be silhouetted against the Milky Way.

You can go to this page (http://aa.usno.navy.mil/data/docs/RS_OneYear.html)to download a table of sun and/or moon data for an entire year from just about anywhere in the world. It lists moonrise/moonset, but not phase. You should be able to get the phases pretty easily from somewhere else and cross-check them with the moonrise and moonset times.

HN
Yep. You can see the New moon in the day. It sets at night. New, crescent, half, gibbous, full, then reverse. Repeat as necessary.

ideagirl
02-21-2007, 05:32 AM
When the moon is dark, is it still possible to see it in the night sky? If the observer knows where it should be? Would it be able to be seen as a dark circle against an even darker night sky? Or - improbablity of improbabilities - a dark circle backdropped against the Milky Way

When the moon is new, it is NOT in the night sky at all. It's not visible because the new moon rises and sets with the sun--so it's there in the daytime, but not at night. During the daytime, when it is in the sky, technically you could see it, but you would have to be looking at or near the sun. When the moon is full, it rises as the sun sets and vice versa... it's opposite the sun, which is why it looks fully lit; when the moon is "dark," it doesn't look lit to us because it's between us and the sun.