APOD: Earthshine and Venus Over Sierra de... (2012 Mar 28)

Comments and questions about the APOD on the main view screen.
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APOD: Earthshine and Venus Over Sierra de... (2012 Mar 28)

Post by APOD Robot » Wed Mar 28, 2012 4:06 am

Image Earthshine and Venus Over Sierra de Guadarrama

Explanation: What just above that ridge? The Moon. Specifically, the Earth's Moon was caught just above the horizon in a young crescent phase. The familiar Moon might look a bit odd as the exposure shows significant Earthshine -- the illumination of the part of the Moon hidden from direct sunlight by the sun-reflecting Earth. Also captured in the image is the bright planet Venus on the right. Venus and Jupiter passed only three degrees from each other last week during a photogenic planetary conjunction. The above image was taken two days ago near Madrid, Spain. The foreground horizon silhouette includes some of the Seven Peaks of the Sierra de Guadarrama mountain range. Just a few minutes after this picture was taken, the Moon set.

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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by owlice » Wed Mar 28, 2012 5:48 am

What a lovely image! Congratulations, Dani!
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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by Ann » Wed Mar 28, 2012 8:22 am

Lovely indeed. The picture looks quite surreal, thanks to the fact that almost the only light we can see, apart from faint "sky-shine" and a number of relatively faint stars, is the Earthshine of the Moon and the light of Venus.

Ann
Last edited by Ann on Wed Mar 28, 2012 10:35 am, edited 1 time in total.
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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by MANUELC » Wed Mar 28, 2012 8:57 am

A beautiful photography. And a lot of work behind her. I hope that it should be the first one and not the last one. Because the first one would not have to be. Congratulations!

Una fotografía preciosa. Y mucho trabajo detrás de ella. Espero que sea la primera y no la última. Porque la primera no tendría que haber sido. Felicidades!

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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by rigelan » Wed Mar 28, 2012 12:15 pm

At what point will we actually see the crescent of Venus?

I have never seen it with my binoculars. I thought with a zoomed in image like this one - I might see it.

I think right now, its not a crescent anyway - its a 3rd quarter phase.

Does it need a specific zoom to see, does the brightness need to be filtered down? How in the world did Galileo see it?

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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by orin stepanek » Wed Mar 28, 2012 12:56 pm

what a beautiful picture! 8-) A silhouetted horizon against a backdrop of a beautiful Earth-shown Luna and a bright Venus! :D Kudos to the photographer! 8-) :wink:
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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by Chris Peterson » Wed Mar 28, 2012 1:54 pm

rigelan wrote:At what point will we actually see the crescent of Venus?
I have never seen it with my binoculars. I thought with a zoomed in image like this one - I might see it.
I think right now, its not a crescent anyway - its a 3rd quarter phase.
I find the phase of Venus to be quite evident when viewed with 8X binoculars. Perhaps the brightness is confusing your eyes; try it during the day, or as soon after sunset as you can find it- against a bright sky it may be easier.

It is often apparent in images made with typical telephoto lenses that Venus is in some partial phase. But the planet is brighter than the Moon, and much brighter than most landscape objects, so to get a nice image often involves substantially overexposing it, which can hide its true shape.
Chris

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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by luigi » Wed Mar 28, 2012 2:10 pm

Chris Peterson wrote:
rigelan wrote:At what point will we actually see the crescent of Venus?
I have never seen it with my binoculars. I thought with a zoomed in image like this one - I might see it.
I think right now, its not a crescent anyway - its a 3rd quarter phase.
I find the phase of Venus to be quite evident when viewed with 8X binoculars. Perhaps the brightness is confusing your eyes; try it during the day, or as soon after sunset as you can find it- against a bright sky it may be easier.

It is often apparent in images made with typical telephoto lenses that Venus is in some partial phase. But the planet is brighter than the Moon, and much brighter than most landscape objects, so to get a nice image often involves substantially overexposing it, which can hide its true shape.
+1 you need to underexpose to show the phase.
Right now is 50% and it's quite evident with a 200mm camera lens even at low magnifications.
From here it will get larger and brighter as the crescent is more and more evident.
Maximum brightness will be on April 30
On May 15 the disc is only 12% illuminated
On May 23 the disc is only 6% illuminated

About the APOD I love it, it's a great scene and the moon touching the horizon is the perfect detail.

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Smaismrmilmepoetaleumibunenugttaviras

Post by neufer » Wed Mar 28, 2012 2:49 pm

Chris Peterson wrote:
rigelan wrote:
At what point will we actually see the crescent of Venus?
I have never seen it with my binoculars. I thought with a zoomed in image like this one - I might see it.
I think right now, its not a crescent anyway - its a 3rd quarter phase.
I find the phase of Venus to be quite evident when viewed with 8X binoculars. Perhaps the brightness is confusing your eyes; try it during the day, or as soon after sunset as you can find it- against a bright sky it may be easier. It is often apparent in images made with typical telephoto lenses that Venus is in some partial phase. But the planet is brighter than the Moon, and much brighter than most landscape objects, so to get a nice image often involves substantially overexposing it, which can hide its true shape.
You might also try dimming by "stopping down" your binocular objective lenses with cardboard to 25mm (or less) a la Galileo:
http://www.hps.cam.ac.uk/starry/galtele.html wrote:
[img3="Galileo's 37mm diameter plano-convex objective lens were
"stopped down" to 25mm (or less) to limit chromatic aberration.
"]http://calitreview.com/images/galileo_telescope_1.jpg[/img3]
<<The story of Galileo's telescope is well known, as he recounted it himself in the Starry Messenger. In July 1609, Galileo was in Venice, when he heard of an invention that allowed distant objects to be seen as distinctly as if they were nearby. In October 1608, a Flemish spectacle-maker by the name of Hans Lipperhey had already applied for a patent (which was refused), and news of the gadget was widespread in Europe by the time Galileo had heard of it. Around the same time, a foreigner turned up in Padua with the instrument; Galileo rushed back to Padua, only to learn that the foreigner had gone to Venice to sell his instrument. Galileo's friend, Paolo Sarpi, had advised the Venetian government against purchasing the instrument from the foreigner, since Galileo could at least match such an invention. By then, Galileo had worked out the principle of the telescope and returned to Venice himself with an eight-power telescope. The Venetian government doubled his salary, though Galileo felt that the original conditions were not honoured.

Galileo gradually improved the power of his telescope, grinding lenses himself, and began observing the heavens. In the first two months of 1610, he was writing The Starry Messenger, and by 12 March, the book was already printed at Venice, dedicated to Cosimo de' Medici.

Galileo continued his observations with his telescope, some of which he conveyed in [anagram] ciphers to Johannes Kepler, who had already responded enthusiastically with the Conversation with Galileo's Sidereal Messenger:

Galileo's discovery of the 'handles' of Saturn was encoded in 'Smaismrmilmepoetaleumibunenugttaviras',
which could be unscrambled as 'Altissimum planetam tergeminum observaui': 'I have observed the highest of the planets three-formed.'

[However,] Kepler deciphered the anagram as 'Salve umbistineum geminatum Martia proles': 'Be greeted, double knob, children of Mars.'

For the discovery of the phases of Venus, the code 'Haec immatura a me jam fru(s)tra leguntur oy' (this was already tried by me in vain too early) hid the [near-anagrammed] message, 'Cynthiae figura(e) aemulatur mater amorum' (The mother of lovers [Venus] imitates the shapes of Cynthia [the moon]').

Despite this [cipher] exchange, Galileo never accepted Kepler's elliptical orbits.

From 1616, Galileo tried to apply his knowledge of the satellites of Jupiter to the determination of longitude at sea. In order to ensure observation at sea, the Tuscan arsenal made for Galileo a headgear which had a telescope attached. Around this time, he also designed a brass 'Jovilabe', a computing device for prediction positions of the satellites. He hoped to gain support from the Spanish crown for this project, but failed.>>
Last edited by neufer on Wed Mar 28, 2012 10:07 pm, edited 3 times in total.
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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by FloridaMike » Wed Mar 28, 2012 5:04 pm

neufer wrote:Smaismrmilmepoetaleumibunenugttaviras
bless you...
Certainty is an emotion. So follow your spindle neurons.

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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by Donnageddon » Wed Mar 28, 2012 7:47 pm

FloridaMike wrote:
neufer wrote:Smaismrmilmepoetaleumibunenugttaviras
bless you...
Add a few more consonants and you might have the name of an Icelandic volcano.

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ALTISSIMUM PLANETAM TERGEMINUM OBSERVAUI

Post by neufer » Wed Mar 28, 2012 10:08 pm

Ben Jonson:
  • Or spunne out Riddles, or weav'd fifty Tomes
    Of Logogriphes, or curious Palindromes;
    .
    *Or pump'd for those hard trifles, ANAGRAMS* ,
    .
    Or *Ecrosticks* , or your finer flames
    Of Egges, and Halbards, Cradles, and a Herse,
    A paire of Sizers, and a Combe in verse;
    Acrosticks, and *Tellesticks* , or jumpe names.
http://www.hps.cam.ac.uk/starry/galtele.html wrote:
<<Galileo continued his observations with his telescope, some
of which he conveyed in [anagram] ciphers to Johannes Kepler,
who had already responded enthusiastically with the
Conversation with Galileo's Sidereal Messenger:

Galileo's discovery of the 'handles' of {SATURNUS} was

encoded in *SMAISMRMILMEPOETALEUMIBUNENUGTTAVIRAS* ,

which could be unscrambled as the ANAGRAM:

*ALTISSIMUM PLANETAM TERGEMINUM OBSERVAUI:

'I have observed the highest of the planets three-formed.'

[However,] Kepler deciphered the anagram as
'Salve umbistineum geminatum Martia proles':
'Be greeted, double knob, children of Mars.'>>
--------------------------------------------------------------
Galileo's discovery of the 'handles' of {SATURNUS} was

encoded in *SMAISMRMILMEPOETALEUMIBUNENUGTTAVIRAS* ,
Image
Mysterium Cosmographicum (1596): Kepler proposed
that the distance relationships between the six
known planets at that time could be understood
in terms of the 5 Platonic solids, enclosed within
a sphere that represented the orbit of {SATURNUS}.
which could be unscrambled as the ANAGRAM:

*ALTISSIMUM PLANETAM TERGEMINUM OBSERVAUI:
..................................
__ <= 5 =>

. {A} [L] T I S
. {S} [I] M U M
. -P- [L] A N E
. {T} [A] M T E
. {R} [G] E M I
. {N} {U} M O B
. {S} [E] R V A
. {U} [I]


Prob. of Equidistant Letter Sequence: [GALIL.] with any skip ~ 1 in 6,180 :!:
Prob. of ANAGRAM of {SATURNUS} on left hand side ~ 1 in 1,004

[GALIL]eo [GALIL]ei (15 February 1564 – 8 January 1642)
Christopher Marlo (26 February 1564 (bapt.) - 30 May 1593)
William Shake-speare (26 April 1564 (bapt.) - 23 April 1616)
---------------------------------------------------------------------
Last edited by neufer on Thu Mar 29, 2012 5:48 pm, edited 6 times in total.
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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by flash » Wed Mar 28, 2012 10:17 pm

APOD Robot wrote:The familiar Moon might look a bit odd as the exposure shows significant Earthshine -- the illumination of the part of the Moon hidden from direct sunlight by the sun-reflecting Earth.
This sentence seems ambiguous (or at least awkward). There are at least two possible interpretations, one of which is plainly wrong! (and this is the one I used when I first read it)

This incorrect interpretation is:
The illumination of the part of the moon (which is) hidden (by the sun-reflecting Earth) from direct sunlight.

Upon re-reading it I have come upon what I hope was the intended interpretation:
The illumination (by the sun-reflecting Earth) of the part of the Moon hidden (by the Moon itself) from direct sunlight.

I'm sure there's someone out there who can grammatically diagram this sentence to better describe the problem.

Diana

Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by Diana » Wed Mar 28, 2012 11:15 pm

APOD Robot wrote:
The familiar Moon might look a bit odd as the exposure shows significant Earthshine -- the illumination of the part of the Moon hidden from direct sunlight by the sun-reflecting Earth.


The sun lit crescent is mostely hidden from view below the mountain ridge, leaving the rest of the lunar disc to be viewed via Earthshine.
??

Diana

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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by Anthony Barreiro » Wed Mar 28, 2012 11:58 pm

A breathtakingly beautiful image.

Regarding seeing the changing phase of Venus, I find a small telescope (I use a 70 mm refractor or 127 mm schmidt cassegrain) at about 80x magnification with a variable polarizing filter works very well. Through binoculars the bright glare overwhelms the tiny apparent size of the planet.
May all beings be happy, peaceful, and free.

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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by Chris Peterson » Thu Mar 29, 2012 12:57 am

flash wrote:
APOD Robot wrote:The familiar Moon might look a bit odd as the exposure shows significant Earthshine -- the illumination of the part of the Moon hidden from direct sunlight by the sun-reflecting Earth.
This sentence seems ambiguous (or at least awkward).
... Earthshine, the indirect illumination of the lunar nightside by sunlight reflected off the Earth.
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Re: APOD: Earthshine and Venus Over Sierra de... (2012 Mar 2

Post by DavidLeodis » Thu Mar 29, 2012 12:35 pm

When I click on the DANIKXT link in the credit I get information that I do not understand (easily done I know!). I wonder if it is just a problem with my Internet connection or does anyone else have a problem working out what is brought up through that link. If not could someone please let me know what that link should bring up? Thanks.

Edit added around 20:00 BST. The link now seems to be OK and brings up a normal looking webpage, which is something it did not do when I did several tries over some time after my initial post.