APOD: A New Year s Crescent (2014 Jan 01)

Comments and questions about the APOD on the main view screen.
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APOD: A New Year s Crescent (2014 Jan 01)

Post by APOD Robot » Wed Jan 01, 2014 5:09 am

Image A New Year s Crescent

Explanation: That's not the young crescent Moon poised above the western horizon at sunset. Instead it's Venus in a crescent phase, captured with a long telephoto lens from Quebec City, Canada, planet Earth on a chilly December 30th evening. The very bright celestial beacon is dropping lower into the evening twilight every day. But it also grows larger in apparent size and becomes a steadily thinner crescent in binocular views as it heads toward an inferior conjunction, positioned between the Earth and the Sun on January 11. The next few evenings will see a young crescent Moon join the crescent Venus in the western twilight, though. Historically, the first observations of the phases of Venus were made by Galileo with his telescope in 1610, evidence consistent with the Copernican model of the Solar System, but not the Ptolemaic system.

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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by tjjharris » Wed Jan 01, 2014 8:56 am

Was the intended word "dropping"?

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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by owlice » Wed Jan 01, 2014 10:44 am

Probably, but it's a holiday so I'm not going to bug the editors about it. (I'll wait until tomorrow. :-D )

This is a lovely shot! And the three APODs that are linked to in the text carry mostly the same hues: grey/black [brown]/white/orange. A nice touch!
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Ann
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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by Ann » Wed Jan 01, 2014 12:50 pm

It's a lovely picture, indeed.

As a color commentator, I'm struck by the contrast between the deep orange-red sunset sky and the brilliantly white, almost blue-white Venus crescent. Of course Venus ins't blue. Still, I would guess that Venus is a little bit less yellow in overall color than the Moon, even though Venus in itself appears to be yellowish-white, and yellower than the Sun.

Obviously Venus is brilliantly lit by the Sun. According to this page, the albedo of Venus is 0.75 - that is, Venus reflects 75% of the sunlight that strikes it. The Moon, by comparison, reflects only 12% of the sunlight that reaches its surface. But on top of that, Venus is closer to the Sun, and so receives more sunlight per unit of its reflective "surface" than the Moon.

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Last edited by Ann on Wed Jan 01, 2014 2:22 pm, edited 1 time in total.
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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by orin stepanek » Wed Jan 01, 2014 12:55 pm

It does go with my (I like) Pictures! :D :yes: :yes: :clap: :clap: :thumb_up: :thumb_up: 8-)
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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by Beyond » Wed Jan 01, 2014 1:29 pm

I never would have guessed that the crescent was venus. Must be a telephoto effect.
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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by Boomer12k » Wed Jan 01, 2014 2:18 pm

Too bad it did not have Mercury in there too, it was close by...at least on my software....

Interesting picture.

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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by Joe Stieber » Wed Jan 01, 2014 10:07 pm

Boomer12k wrote:Too bad it did not have Mercury in there too, it was close by...at least on my software....
Indeed, it was only about 17.5 degrees from Venus on December 30th, 2013, the date of the picture. However, Mercury was also just a couple of degrees from the sun a day after superior conjunction, setting about the same time as the sun. It would have been a very considerable challenge just to see or image Mercury, let alone get it into a picture with Venus on that date. Regardless, the limited field of view of this telephoto image of the crescent Venus would have certainly precluded including Mercury.

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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by Anthony Barreiro » Wed Jan 01, 2014 10:24 pm

Boomer12k wrote:Too bad it did not have Mercury in there too, it was close by...at least on my software....

Interesting picture.

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Mercury was conjunct to the Sun last Saturday, and is only 2 degrees from the Sun today. Venus, by comparison, is 15 degrees from the Sun today. Mercury moving direct will pass Venus moving retrograde on January 7, but only six degrees from the Sun and extremely challenging to see. Alas, probably not a photo opportunity. Mercury will climb into a reasonably good evening apparition from the northern hemisphere, reaching greatest elongation of 18 degrees on January 31, by which time Venus will have become 2014's morning star.

I've been enjoying setting up my little refractor on the sidewalk in front of my home or atop the hill in a nearby park and showing passersby crescent Venus. Most people say she looks like the Moon. In addition to the simple beauty of the image, this affords a teachable moment: why does Venus look like a crescent Moon? where is the light coming from? how does the orbit of Venus compare to the orbit of the Earth? how did Galileo figure out that Venus must be orbiting the Sun and not the Earth?

I'm curious about the proportions in today's apod. I would guess that the trees look big and in focus because they're far from the camera. And is the building on the left farther than the trees?

Happy Gregorian new year to one and all, and apologies for my cultural centrism to those who follow other calendars. :ssmile:
May all beings be happy, peaceful, and free.

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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by DavidLeodis » Thu Jan 02, 2014 2:22 pm

It's a great photo. Without the text to it I would have thought it was our Moon as a very thin crescent.

I have however a query. Though it does not state the year the explanation would seem to imply the image was taken on December 30th 2013. In the EXIF information found through the image properties it however states:- "Create Date 2012:01:01 00:00-05:00" but "Modify Date 2013:12:30 21:55:51-05:00". I wonder therefore if it was taken at (or close to) the very start of 2012 January 1st but was then modified on 2013 December 30th :?:

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Anthony Barreiro
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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by Anthony Barreiro » Thu Jan 02, 2014 5:34 pm

DavidLeodis wrote:It's a great photo. Without the text to it I would have thought it was our Moon as a very thin crescent.

I have however a query. Though it does not state the year the explanation would seem to imply the image was taken on December 30th 2013. In the EXIF information found through the image properties it however states:- "Create Date 2012:01:01 00:00-05:00" but "Modify Date 2013:12:30 21:55:51-05:00". I wonder therefore if it was taken at (or close to) the very start of 2012 January 1st but was then modified on 2013 December 30th :?:
Unlikely. On January 1, 2012 Venus was gibbous, not crescent. My first guess would be that the photographer didn't set the date on his camera.
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Re: APOD: A New Year s Crescent (2014 Jan 01)

Post by DavidLeodis » Thu Jan 02, 2014 7:39 pm

Thanks Anthony. :) I thought it may be that reason, but I did wonder if it might not be.