Author Topic: When you watch the sky... (Read 347280 times)

Markus · « **Reply #20 on:** March 02, 2006, 08:29:45 pm »

Hi folks,

it's not like you have to know the Messier catalogue by heart to be allowed to say something here.

For instance I have seen a terrific moon tonight: A very thin crescent, almost "lying" horizontally like a "ship of Luna", with a clear earthshine. Beautiful.... That's stargazer stuff, too.

Right now it's sinking behind a neighbouring house, with a strong reddish hue.

Cheers!

Markus

Aluqak · « **Reply #21 on:** March 03, 2006, 01:54:58 pm »

Hey! I saw it too. Last night in the bus to Ottawa!!!
It was near the horizon (about 8pm local time) and was yellowish-orange. Pretty stuff! :w00t:

Markus · « **Reply #22 on:** March 05, 2006, 06:06:21 pm »

Hi there,

when I see the moon these days I have to think of what will happen at the next new moon...

Lepaca Draconis Dies!

But you'll have to bear a whole thread on this special topic soon...

Cheers!

Markus

Markus · « **Reply #23 on:** September 09, 2006, 12:23:16 pm »

Hi folks,

something I observed last Friday night: In a crater named Hahn, near the Eastern rim of the moon, I saw the central mountain shortly after midnight. It was visible as an island of light in a pool of pitchblack darkness, because on the waning moon the sun had already set beneath the crater wall for any point on the bottom of Hahn. The peak of the central mountain, however, was high enough to peek out of the darkness and still get some last sunrays.

That was what I saw shortly after midnight. One and a half hour later, that speck of light was gone. As seen from that mountain peak on the moon, the sun had set at last.

This is nothing exotic or unexpected, of course, but still I found it impressive: I had watched the moon waning within just a few hours, and I had seen from above a sunset on the moon.

Cheers, and don't forget to look up occasionally!

Markus Astronomicus

Ereshkigal · « **Reply #24 on:** September 09, 2006, 07:47:15 pm »

Somedays I have to get up at 4:30am (

) and on my way to the shower I always look out the window. So the other day I noticed the moon high in the sky, but not toooo high up there. It was very very shiny and round...looking kind of yellowish. It wasn't full moon...I think...but it was a pretty view.

Elizabeth · « **Reply #25 on:** September 11, 2006, 12:13:41 pm »

I spent the last days of my Israeli vacation in Eilat, the most southern city in the country. In the sorrounding area, there's the Red Canyon: I took a beautiful walk through it
with my sister and brother in law, but at noon, 'cause during the day, the desert summer make excursions rather impossible.

When we left the place, on one side of the road, the Sun was setting and on the other, the Moon was rising. It was gorgeeeouuusss!!! I'll share some pics pretty soon, I hope

Namarie!

Luth · « **Reply #26 on:** September 11, 2006, 01:55:18 pm »

Hi people!

Yesterday I saw the moon very low on the sky, very very red, and the more amazing: ENORMOUS! (or giant is better?). It looked really beautiful, and I wondered how was the moon so big.

High Priest, you here?

Markus · « **Reply #27 on:** September 11, 2006, 02:05:39 pm »

Invoke me, Luth,

if you there's something you wanna know. Offering wine or mead usually works to make me appear.

Cheers!

Markus Astronomicus

Luth · « **Reply #28 on:** September 11, 2006, 03:59:03 pm »

Offers a truck full of red wine.

Oh High Priest of Full Moons, of Giant Craters and Partial Eclipses!

Offers two trucks of mead.

Please, appear to me, a simple mortal who wish your high wisdom of the Moon!

Offers a Capra to the High Priest.

Aluqak · « **Reply #29 on:** September 11, 2006, 04:03:22 pm »

*snif*....

... *snif-snif*....

...... *SNIF!*... Wine and meat

!!!
*Instals himself close to Markus to share his food.... and to (obviously) listen his wise answer to Luth's request

*

Markus · « **Reply #30 on:** September 11, 2006, 04:20:25 pm »

Listens attentively, sniffs, yawns and stretches

Happens to push a giant but curiously listening anglerfish off the edge of the world

Tastes a tiny little bit of the wine and mead, considers it good and begins to reply:

Hi Luth,

there are two things to be explained here: The beautyful red colour and the (apparently) huge size.

The colour is due to our atmosphere. Imagine the moon right above your head. When you look at it, you look straight out of the atmosphere along the shortest possible way. Now imagine the moon on the horizon. When you look at it now, you look along the ground for a long way. Your gaze goes through the densest part of the atmosphere for many, many kilometres. So when you see the moon on the horizon you look through a thick layer of air. But this air hinders the light! The shorter its wavelength - the bluer the colour - the more it's absorbed by the air. So the red part of the light can reach you more easily than the blue one. Much of the blue light is filtered out, what remains is mostly red - hence the colour! This doesn't work for the moon only but as well for the sun or any other extraterrestrial lightsource.

And why does the moon look so big to you? There are two reasons here: The first is that the moon is rather close to us these days. You have heard that it doesn't follow a circular orbit but an elliptical, so once a month it's closer to the earth, once farther away. Now it's rather close, so it looks bigger in the sky.

However, this difference is so small that only quite experienced skygazers will notice it. Here the second reason comes into play, the so-called moon-illusion. For some reason not yet understood, objects near the horizon seem bigger to us. You can measure the size of the moon on the horizon and in the height and both will turn out to be equal! Still our brain lets us see the moon bigger when it's near the horizon. Again, the same works for the sun or the constellations. All seem bigger on the horizon due to this optical illusion. Noone knows completely why, but who cares - enjoy it!

Cheers!

Markus

Gulps down the content of the wine and mead trucks and falls asleep again

Luth · « **Reply #31 on:** September 11, 2006, 04:37:58 pm »

Thanks, oh High Priest of the Moon Optical Effects!

Goes to summarize the content of Markus' reply to Xiquet, as he was too lazy to read so much English text.

Elizabeth · « **Reply #32 on:** September 12, 2006, 09:38:19 am »

Invokes High Preast Markus Astronomicus offering him a big amount of the best Elvish wine

When I took some of the pics in the desert, the Moon wasn't at the horizon, but pretty high in the sky, and still looked bigger than in other places! Not to mention that it was bright yellow. Does the desert have anything to do with this fenomenon?

Markus · « **Reply #33 on:** September 12, 2006, 10:05:46 am »

Smells some wine, stirs in his sleep

Yawns and stretches, again pushing that poor fish off the world accidentally

Eya Livi,

to reply to that I need to know what you mean by "pretty high". Approximately how many fists on your outstretched arm? One? Two? Five? More?

Drinks the wine. All of it.

Oh, and I need to know where I can get more of this tasty stuff. Or rather: I need to get more of this stuff.

Cheers!

Markus

Elizabeth · « **Reply #34 on:** September 13, 2006, 08:37:12 pm »

offers some more Elvish wine to the High Priest

Well... that's a pretty difficult question, oh Great One! I was visiting a canyon, so the landscape around was also irregular. But I think that around 4-5 fists would do.

Markus · « **Reply #35 on:** September 13, 2006, 11:19:36 pm »

Hi Liv,

sorry for being unclear: I meant the mathematical, the ideal horizon. The one you get when all mountains and valleys disappear, the line that's exactly 90° from the zenith, from the point right above your head.

But I think that the apparent size may have been increased by the desert landscape indeed. The yellow colour comes from the same effect that is responsible for the red closer to the horizon. This effect is weaker in greater height, hence it makes the light not red but only yellow. You can observe this very well at sunrise, for instance: The first sunlight is dim and red. Then it turns stronger and orange, yellow, finally white as the sun climbs higher in the sky. Does that answer your question?

Cheers!

Markus

Elizabeth · « **Reply #36 on:** September 14, 2006, 09:38:59 am »

Yes, it does answer my question. Thank you very much, Markus!

Gives the High Priest some more Elvish wine, in grattitude

Lucy · « **Reply #37 on:** September 14, 2006, 09:52:40 am »

*calls the ambulance for carrying Markus in the detoxicating hospital*

Elizabeth · « **Reply #38 on:** September 14, 2006, 11:28:46 am »

Oh no, Lucy, Elvish wine would never hurt anyone, especially an immortal!

Lucy · « **Reply #39 on:** September 14, 2006, 11:47:40 am »

Ah, OK then!

*stops worrying for our High Priest*

Lepaca more Elvish wine for everybody!

News:

Author Topic: When you watch the sky... (Read 347280 times)