PDA

View Full Version : The Moon on Feb 19...



khorsed1018
2007-Feb-19, 08:57 AM
Hi all, I'm new here...I do not know much about astronomy :shhh: , but something about the moon tonight struck my curiosity :think: . What I saw here in Scottsdale, Arizona around 7:20 pm looked different from anything I've ever seen. The moon had a dark circle directly in front of it, with only a tiny sliver of light showing on the bottom. The dark circle completely moved down and covered the moon and I haven't seen it (the moon) since that happened. Yes, I know, flame me all you want LOL. I'd be ever so glad to hear what the heck this was. Thanks in advance!

Kristin

Jason Thompson
2007-Feb-19, 09:18 AM
Very simple. The Moon is nearly new, which means that the sunlit side is facing mostly away from Earth. All you will see in that case is a thin sliver of light on the bottom just around the time of sunset, just as you describe. The 'dark circle' is simply the shaded side of the Moon. And the reason you haven't seen the Moon since is not that the 'dark circle' moved to obscure it, but that it set shortly after sunset and is no longer visible in your sky. You won't see the Moon again until around sunset tonight, when it will look very similar but with a slightly thicker crescent.

Jeff Root
2007-Feb-19, 09:25 AM
Hey, Kristin!

First, you must have seen the Moon on February 18, not 19, since
it is only 2:12 AM on the 19th in Arizona as I type.

Considering that the Moon was "new" on the 17th, I'd say you did
really well to see it all on the 18th. You must have a clear horizon
to your west.

To be both flippant and accurate simultaneously, I'll just say that
what you saw was the new Moon in the arms of the old.

-- Jeff, in Minneapolis

Kaptain K
2007-Feb-19, 09:31 AM
1) Welcome to the forum.
2) I assume that you meant Feb 18.
3) Last night the Moon was just past new. A very thin cresent, that set at 7:44 pm, which would explain why you haven't seen it since.

khorsed1018
2007-Feb-19, 05:00 PM
Very simple. The Moon is nearly new, which means that the sunlit side is facing mostly away from Earth. All you will see in that case is a thin sliver of light on the bottom just around the time of sunset, just as you describe. The 'dark circle' is simply the shaded side of the Moon. And the reason you haven't seen the Moon since is not that the 'dark circle' moved to obscure it, but that it set shortly after sunset and is no longer visible in your sky. You won't see the Moon again until around sunset tonight, when it will look very similar but with a slightly thicker crescent.
THANK YOU so much! I really appreciate your fast reply and explanation. Now it makes sense to me :)

Kristin

khorsed1018
2007-Feb-19, 05:02 PM
Hey, Kristin!

First, you must have seen the Moon on February 18, not 19, since
it is only 2:12 AM on the 19th in Arizona as I type.

Considering that the Moon was "new" on the 17th, I'd say you did
really well to see it all on the 18th. You must have a clear horizon
to your west.

To be both flippant and accurate simultaneously, I'll just say that
what you saw was the new Moon in the arms of the old.

-- Jeff, in Minneapolis

Heh, oops, yes, I meant on February 18 :shifty:

They sky was actually pretty clear last night. Up where I live, they do not allow street lights that could 'ruin' the view, so it's super dark and I get to see some beautiful skies :) Especially in the summer time!

Kristin

khorsed1018
2007-Feb-19, 05:03 PM
1) Welcome to the forum.
2) I assume that you meant Feb 18.
3) Last night the Moon was just past new. A very thin cresent, that set at 7:44 pm, which would explain why you haven't seen it since.


Thanks for the info! I will see you around the forum!

Kristin

Kaptain K
2007-Feb-20, 02:30 AM
If you go out and look tonight, you will see the crescent Moon (with a fatter crescent) above and to the right of Venus. Lovely!

khorsed1018
2007-Feb-20, 02:34 AM
If you go out and look tonight, you will see the crescent Moon (with a fatter crescent) above and to the right of Venus. Lovely!

Excellent! Too bad it's been pouring all day! It's raining again here in AZ...maybe it'll clear up so I can go look :)

Kristin

01101001
2007-Feb-20, 02:35 AM
If you go out and look tonight, you will see the crescent Moon (with a fatter crescent) above and to the right of Venus. Lovely!

Be sure to look within about an hour of sunset. The moon is still close to the sun, and where the sun goes now, the moon soon follows.

AGN Fuel
2007-Feb-20, 02:43 AM
Just as a point of interest, if you look closely, details within the 'dark circle' of the moon can be seen as they are being illuminated by light reflecting off the Earth (which from the perspective of the moon would have been almost full).

You were seeing the night side of moon by 'Earthshine'!

publius
2007-Feb-20, 03:26 AM
Tonight I noticed the same thing. Tiniest bright sliver, with the "dark remainder" of the disc very visible, with the rim most noticeable. The dark part was so relatively bright I actually looked at it for a long time. While I've seen this before, it doesn't usually seem this bright.

-Richard

bird2brain
2007-Feb-20, 03:55 AM
OK, so I went out on Feb 19 to look at the beautiful Moon and Venus. At 5:30 (San Jose Local time) my friend was first to spot the moon, but the sky was still a bit bright to spot Venus. Again, she spotted a small dot near the moon (her eyes are younger than mine) but it was not where I expected venus to be. Instead of three finger down and to the left, it was oen finger down and to the right. Huh. In the few minutes we watched, it seemed to move a bit, way faster than I expected to see things change wetween the moon and planet.

We moved my car the the roof of the parking structure so I could break out the binocs and look again, but the bright spot was not where we left if a few minutes ago. The next bright spot we saw (this is about ive minutes later) was ABOVE AND TO THE LEFT OF THE MOON! (Three fingers!) I thought to myself, "Self, this can't be right" Pretty soon, it was a full fist, then a fist and a thumb. In the space of the 1/2 hour I watched, it must have moved 45 degrees across the sky. I was forced to leave and lost track of it, but this seemed too fast for a planet and waaayy too slow for a plane or satellite (unless it was near geosync).

BTW, it WASN'T Venus. She showed right on time and right in place and stayed put just as expected. The mystery object started out brighter and faded compared to Venus, but not like a satellite which comes and goes in a few minutes. I couldn't find anything about it on Heavens-Above, either.

What was it?!!!

Gillianren
2007-Feb-20, 05:26 AM
Excellent! Too bad it's been pouring all day! It's raining again here in AZ...maybe it'll clear up so I can go look :)

Likewise in Washington. But it's always raining here! Hence "rain forest," which is not that far from here.

Jason Thompson
2007-Feb-20, 05:05 PM
THANK YOU so much! I really appreciate your fast reply and explanation. Now it makes sense to me :)

Kristin

You're very welcome. We're always happy to answer questions from people who demonstrate an eagerness to learn and understand. And don't worry about being flamed. There are, broadly speaking, two types of people who ask questions about stuff they've seen. They can be summarised by these two questions:

1: I know nothing about astronomy, and last night I saw (description of object/event). Does anyone know what it was?

2: I know nothing about astronomy, and last night I saw (description of object/event). It can't have been a star or planet or plane, so it must have been an alien spaceship, and anyone who says it isn't doesn't know what they're talking about because I saw it and they didn't.

I leave it to you to work out which of those provokes the more 'flame-like' response....

Jason Thompson
2007-Feb-20, 05:11 PM
but this seemed too fast for a planet and waaayy too slow for a plane or satellite (unless it was near geosync).

Or unless the plane was travelling largely towards you, in which case it can seem to move a lot more slowly because you're only seeing the lateral component of its motion. If I had to choose, that's what my money would be on.

I live not a million miles from an airport. The sky is filled with planes. Several of them move towards the town, then veer off to one side to make their approach to the airport. When they're heading almost straight in the result is a very bright light in the sky which is almost static. On more than one occasion I have mistaken them for Venus, until they suddenly fade and start moving across the sky as the plane turns.

astromark
2007-Feb-20, 06:39 PM
There is always a explanation; You just may not know what it is. Yet.
It is foolish to jump to conclusions when all the information is not available.
Show a little tolerance for the unknown is simply that. Unknown.
Very high probability that your sighting was a aircraft descending toward you. Think about the suns angle of reflection from the fuselage. Where is the airfield in that direction?. . . There is always more information than you have.

Maksutov
2007-Feb-21, 08:30 AM
Tonight I noticed the same thing. Tiniest bright sliver, with the "dark remainder" of the disc very visible, with the rim most noticeable. The dark part was so relatively bright I actually looked at it for a long time. While I've seen this before, it doesn't usually seem this bright.

-RichardDuring February through April, the ecliptic as seen in the early evening is almost perpendicular to the horizon, for observers in the Northern Hemisphere, at latitudes between ~40 and ~20 degrees.

This produces the effect where the few days old Moon (and planets in that vicinity) stays above the horizon much longer than usual, allowing for views in about total darkness that would otherwise be unobtainable.

The same geometry applies to the ecliptic just before twilight during August through October.

Therefore the best times to spot Mercury (for the referenced latitudes) are when it's in the evening sky during February/April and in the morning sky during August/October.