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Astronomy Picture of the Day 4-17-02
NASA ^
| 11-8-99
| Robert Nemiroff and Jerry Bonnell
Posted on 04/17/2002 6:55:08 PM PDT by petuniasevan
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
November 8, 1999
Lunation
Credit: António Cidadão
Explanation: Our Moon's appearance changes nightly. This slow-loading time-lapse sequence shows what our Moon looks like during a lunation, a complete lunar cycle. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The Moon always keeps the same face toward the Earth. The Moon's apparent size changes slightly, though, and a slight wobble called a libration is discernable as it progresses along its elliptical orbit. During the cycle, sunlight reflects from the Moon at different angles, and so illuminates different features differently. A full lunation takes about 29.5 days, just under a month (moon-th).
TOPICS: Astronomy; Astronomy Picture of the Day; Miscellaneous; Science
KEYWORDS: astronomy; image; libration; lunation; moon; orbit; phases; photography; satellite
The regular site is down today, so I went to a mirror site for this great archive pic.
Enjoy!
Get on the APOD PING list! 
To: MozartLover; Joan912; NovemberCharlie; snowfox; Dawgsquat; viligantcitizen; theDentist; grlfrnd...
APOD PING!
To: petuniasevan;
Another APOD ping! This is great of the moon, Petuniasevan.
3
posted on
04/17/2002 7:04:41 PM PDT
by
Slip18
To: TxBec
You have to see this!
4
posted on
04/17/2002 7:05:13 PM PDT
by
Slip18
To: petuniasevan
That one is really neat.
To: petuniasevan;Pete-R-Bilt
just wonderful. thank you.
To: petuniasevan
I should hit the abuse button! You're mooning me!
7
posted on
04/17/2002 7:20:04 PM PDT
by
snowfox
To: petuniasevan
Wonderful!
Thanks.
To: petuniasevan
Beautiful
9
posted on
04/17/2002 7:33:53 PM PDT
by
callisto
To: petuniasevan
bump for later viewing
To: petuniasevan
When I show this sequence to others they are always fascinated. The moon moves so slowly that most are unaware of the amount of bobbing and weaving that goes on each month.
To: snowfox
I should hit the abuse button! You're mooning me!How WUDE!!
This is a great sequence! I'll have to show it to my daughter in the morning!
12
posted on
04/17/2002 8:44:44 PM PDT
by
SuziQ
To: petuniasevan
Thanks. A person could get dizzy watching that one.
The site is up now and yesterday's selection was The Glory
To: leadpenny
some of those pictures a breath-taking! I've noticed a "rainbow circle around the sun" recently myself and have seen them several times on clear days. I wondered about them and now I know what they are. Thanks :)
14
posted on
04/18/2002 3:38:17 AM PDT
by
TxBec
To: Slip18
too cool! Will have to show this to the boys and make this a regular stop for us.
15
posted on
04/18/2002 3:47:28 AM PDT
by
TxBec
To: petuniasevan
would you mind adding me to the APOD ping list? thanks!
16
posted on
04/18/2002 3:48:22 AM PDT
by
TxBec
To: petuniasevan
Awesome! :)
17
posted on
04/18/2002 7:11:12 AM PDT
by
Joan912
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