APOD: Brisbane Sunset Moonset (2014 May 01)

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Expand view Topic review: APOD: Brisbane Sunset Moonset (2014 May 01)

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by eladnitram » Fri May 02, 2014 12:54 pm

Nitpicker wrote:
geckzilla wrote:
eladnitram wrote:In comparing this image to yesterday's APOD, it occurs to me that one of the images is "flipped." Since totality didn't occur until after sunset in Australia, it doesn't seem possible that the moon would have eclipsed the left/upper left of the sun in Brisbane and then the upper right of the sun by the time it set in Adelaide, 1300 miles to the west. Am I missing something?
That's a good observation, but neither image is flipped. The moon does not take a straight path across the sun and the location does make a difference for how much of the sun is covered by the moon during an eclipse. I recommend using some planetarium software (I use Stellarium, it's free and pretty easy to use) to simulate views of various events from different places on the planet. That is the easiest and most intuitive way to get a feel for how the moon and sun were positioned for these two pictures to be possible.
From Adelaide, the greatest extent of the eclipse was observed about and hour before sunset.
Nice animation here shows the path of the eclipse shadow which helps to see why the view from Adelaide was different than from Brisbane:

http://en.wikipedia.org/wiki/Solar_ecli ... l_29,_2014

Also, cool use of Google maps to show the view of the eclipse from any position at various times:

http://xjubier.free.fr/en/site_pages/so ... ag=1&Max=1

Both help to see that the view was differnt, even from geographically close positions.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by DavidLeodis » Fri May 02, 2014 12:06 pm

geckzilla wrote:Holy photons, Batman. The Universe is practically made of shadows.
At 14 plus billion years old the Universe is probably now only a shadow of its former self! :)

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by Nitpicker » Fri May 02, 2014 2:26 am

geckzilla wrote:
eladnitram wrote:In comparing this image to yesterday's APOD, it occurs to me that one of the images is "flipped." Since totality didn't occur until after sunset in Australia, it doesn't seem possible that the moon would have eclipsed the left/upper left of the sun in Brisbane and then the upper right of the sun by the time it set in Adelaide, 1300 miles to the west. Am I missing something?
That's a good observation, but neither image is flipped. The moon does not take a straight path across the sun and the location does make a difference for how much of the sun is covered by the moon during an eclipse. I recommend using some planetarium software (I use Stellarium, it's free and pretty easy to use) to simulate views of various events from different places on the planet. That is the easiest and most intuitive way to get a feel for how the moon and sun were positioned for these two pictures to be possible.
From Adelaide, the greatest extent of the eclipse was observed about and hour before sunset.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by FloridaMike » Thu May 01, 2014 9:46 pm

geckzilla wrote:
BillBixby wrote:
geckzilla wrote:Holy photons, Batman. The Universe is practically made of shadows.
Shadows, what dark matter is all about. :wink:
Turns out dark matter is just one big bug in the system where a mass object continues invisibly on its trajectory in place of were a photon was absorbed / ended. Biggest memory leak ever.
Maybe that is what is wrong with Otto...

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by Beyond » Thu May 01, 2014 9:10 pm

Holy big bug, Batman. Does the Dark really matter?

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by geckzilla » Thu May 01, 2014 8:33 pm

BillBixby wrote:
geckzilla wrote:Holy photons, Batman. The Universe is practically made of shadows.
Shadows, what dark matter is all about. :wink:
Turns out dark matter is just one big bug in the system where a mass object continues invisibly on its trajectory in place of were a photon was absorbed / ended. Biggest memory leak ever.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by BillBixby » Thu May 01, 2014 7:55 pm

geckzilla wrote:Holy photons, Batman. The Universe is practically made of shadows.
Shadows, what dark matter is all about. :wink:

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by geckzilla » Thu May 01, 2014 5:13 pm

Holy photons, Batman. The Universe is practically made of shadows.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by Chris Peterson » Thu May 01, 2014 3:50 pm

geckzilla wrote:
Chris Peterson wrote:The Moon always casts a shadow except during total lunar eclipses.
The moon casts a meager shadow during a total lunar eclipse now thanks to our city lights.
Well, yes. But if we're looking at shadows of light sources other than the Sun, both the Earth and Moon cast thousands from individual stars. Even the Sun casts shadows from other stars.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by geckzilla » Thu May 01, 2014 3:21 pm

Chris Peterson wrote:The Moon always casts a shadow except during total lunar eclipses.
The moon casts a meager shadow during a total lunar eclipse now thanks to our city lights.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by Chris Peterson » Thu May 01, 2014 3:15 pm

Oblivious wrote:Umm... isn't the moon suppose to be in opposition for the sun to cast a shadow? Just saying.
How can the Sun cast a shadow at all? It is the light source. The Earth always casts a shadow. The Moon always casts a shadow except during total lunar eclipses.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by geckzilla » Thu May 01, 2014 3:09 pm

eladnitram wrote:In comparing this image to yesterday's APOD, it occurs to me that one of the images is "flipped." Since totality didn't occur until after sunset in Australia, it doesn't seem possible that the moon would have eclipsed the left/upper left of the sun in Brisbane and then the upper right of the sun by the time it set in Adelaide, 1300 miles to the west. Am I missing something?
That's a good observation, but neither image is flipped. The moon does not take a straight path across the sun and the location does make a difference for how much of the sun is covered by the moon during an eclipse. I recommend using some planetarium software (I use Stellarium, it's free and pretty easy to use) to simulate views of various events from different places on the planet. That is the easiest and most intuitive way to get a feel for how the moon and sun were positioned for these two pictures to be possible.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by geckzilla » Thu May 01, 2014 3:00 pm

Oblivious wrote:Umm... isn't the moon suppose to be in opposition for the sun to cast a shadow? Just saying.
The moon is in opposition from the sun during a full moon or lunar eclipse. The moon is in conjunction with the sun for a new moon or solar eclipse.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by eladnitram » Thu May 01, 2014 2:41 pm

In comparing this image to yesterday's APOD, it occurs to me that one of the images is "flipped." Since totality didn't occur until after sunset in Australia, it doesn't seem possible that the moon would have eclipsed the left/upper left of the sun in Brisbane and then the upper right of the sun by the time it set in Adelaide, 1300 miles to the west. Am I missing something?

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by bystander » Thu May 01, 2014 1:46 pm

Beyond wrote:Bug?? The answer is... RAID. But I don't know what the four letters stand for, so that's as far as I can help.
In IT RAID means redundant array of independent disks. It is a method of reducing data loss due to disk failure. I don't think it will help in getting rid of Otto's recurring bug.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by MadMan » Thu May 01, 2014 12:26 pm

Oblivious wrote:Umm... isn't the moon suppose to be in opposition for the sun to cast a shadow? Just saying.
That was only true when Pluto was a planet :lol2:

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by Boomer12k » Thu May 01, 2014 12:08 pm

Interesting.


:---[===] *

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by Oblivious » Thu May 01, 2014 11:43 am

Umm... isn't the moon suppose to be in opposition for the sun to cast a shadow? Just saying.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by Beyond » Thu May 01, 2014 11:06 am

Bug?? The answer is... RAID. But I don't know what the four letters stand for, so that's as far as I can help.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by geckzilla » Thu May 01, 2014 4:30 am

I haven't been able to squash that bug because I can't figure out why it does that. I have tried. Oh, how I've tried.

Re: APOD: Brisbane Sunset Moonset (2014 May 01)

by Beyond » Thu May 01, 2014 4:20 am

Well that's neat! There's one more copy of today's APOD, than the number of times one see's the eclipsed moon in the APOD. I'm thinking a 6 APOD day is a record???
It would seem that Otto needs a couple of drops of oil.

APOD: Brisbane Sunset Moonset (2014 May 01)

by APOD Robot » Thu May 01, 2014 4:10 am

Image Brisbane Sunset Moonset

Explanation: In skies over Brisbane at the southeastern corner of Queensland, Australia, Planet Earth, the Sun and New Moon set together on April 29. There the celestial line-up, the first solar eclipse of 2014, was seen as a partial solar eclipse. This dramatic composite is a digital stack of images taken about 5 minutes apart with telephoto lens and solar filter. It follows the eclipse in progress, approaching a western horizon where crepuscular rays from cloud banks in silhouette joined the silhouetted Moon. From Brisbane, the maximum eclipse phase with the Moon covering about 25% of the Sun occurred just after sunset. Only from a remote spot on the continent of Antarctica was it even possible to see the eclipse in its brief annular phase, the entire dark lunar disk surrounded by a thin, bright ring of fire.

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