APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4534
Joined: Fri Dec 04, 2009 3:27 am

APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by APOD Robot » Sat Jan 20, 2018 5:05 am

Image Old Moon in the New Moon's Arms

Explanation: Also known as the Moon's "ashen glow" or the "Old Moon in the New Moon's arms", earthshine is earthlight reflected from the Moon's night side. This stunning image of earthshine from a young crescent moon was taken from Las Campanas Observatory, Atacama Desert, Chile, planet Earth near moonset on January 18. Dramatic atmospheric inversion layers appear above the Pacific Ocean, colored by the sunset at the planet's western horizon. But the view from the Moon would have been stunning, too. When the Moon appears in Earth's sky as a slender crescent, a dazzlingly bright, nearly full Earth would be seen from the lunar surface. A description of earthshine, in terms of sunlight reflected by Earth's oceans in turn illuminating the Moon's dark surface, was written 500 years ago by Leonardo da Vinci.

<< Previous APOD This Day in APOD Next APOD >>
[/b]

Boomer12k
:---[===] *
Posts: 2691
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by Boomer12k » Sat Jan 20, 2018 8:25 am

I saw it earlier.... but it was a bit cloudy...

:---[===] *

heehaw

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by heehaw » Sat Jan 20, 2018 11:10 am

I have read that Earthshine (the reflected-back-to-us glow of our own planet) is studied spectroscopically, so as to know what the spectrum of a life-bearing planet looks like, for guidance on our examination of the spectra of planets of distant stars.

ta152h0
Schooled
Posts: 1398
Joined: Mon Aug 29, 2005 12:46 am
Location: Auburn, Washington, USA

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by ta152h0 » Sat Jan 20, 2018 2:32 pm

Very poetic
Wolf Kotenberg

sillyworm2

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by sillyworm2 » Sat Jan 20, 2018 4:41 pm

What a Beautiful image!

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18759
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by neufer » Sat Jan 20, 2018 5:03 pm

heehaw wrote:
I have read that Earthshine (the reflected-back-to-us glow of our own planet) is studied spectroscopically, so as to know what the spectrum of a life-bearing planet looks like, for guidance on our examination of the spectra of planets of distant stars.
https://en.wikipedia.org/wiki/Planetshine#Earthshine wrote: <<Leonardo da Vinci explained the Earthshine phenomenon in the early 16th century when he realized that both Earth and the Moon reflect sunlight at the same time. Light is reflected from the Earth to the Moon and back to the Earth as earthshine.

Earthshine is used to help determine the current albedo of the Earth. The data are used to analyze global cloud cover, a climate factor. Oceans reflect the least amount of light, roughly 10%. Land reflects anywhere from 10–25% of the Sun's light, and clouds reflect around 50%. So, the part of the Earth where it is daytime and from which the Moon is visible determines how bright the Moon's earthshine appears at any given time. Studies of earthshine can be used to show how the Earth's cloud cover varies over time. Preliminary results show a 6.5% dip in cloud cover between 1985 and 1997 and a corresponding increase between 1997 and 2003. This has implications for climate research, especially with regards to global warming. All clouds contribute to an increased albedo, however some clouds have a net warming effect because they trap more heat than they reflect, while others have a net cooling effect because their increased albedo reflects more radiation than they trap heat. So while the Earth's albedo is measurably increasing, the uncertainty over the amount of heat trapped means the overall effect on global temperature remains unclear.>>
https://en.wikipedia.org/wiki/Deep_Space_Climate_Observatory wrote: <<Deep Space Climate Observatory [DSCOVR] is a NOAA space weather and Earth observation satellite. It was launched by SpaceX on a Falcon 9 launch vehicle on February 11, 2015 from Cape Canaveral. It is in a Lissajous orbit at the Sun-Earth L1 Lagrangian point, 1,500,000 km from Earth, to monitor variable solar wind condition, provide early warning of approaching coronal mass ejections and observe phenomena on Earth including changes in ozone, aerosols, dust and volcanic ash, cloud height, vegetation cover and climate. At this location it has a continuous view of the Sun and of the sunlit side of the Earth. The satellite is orbiting the Sun-Earth L1 point in a six-month period, with a spacecraft-Earth-Sun angle varying from 4 to 15 degrees. It takes full-Earth pictures about every two hours and is able to process them faster than other Earth observation satellites.

DSCOVR started orbiting around L1 by June 8, 2015, just over 100 days after launch. After the spacecraft arrived on site and entered its operational phase, NASA began releasing near-real time images of Earth through the EPIC instrument's website.>>
....................................................................................
National Institute of Standards and Technology Advanced Radiometer (NISTAR) measures irradiance of the sunlit face of the Earth. This data is to be used to study changes in Earth's radiation budget caused by natural and human activities. The radiometer measures in four channels:
  • For total radiation in ultraviolet, visible and infrared in range of 0.2-100 µm.
    For reflected solar radiation in ultraviolet, visible and near infrared in range of 0.2-4 µm.
    For reflected solar radiation in infrared in range of 0.7-4 µm.
    For calibration purposes in range of 0.3-1 µm.
Art Neuendorffer

SteveFrench
Asternaut
Posts: 1
Joined: Sat Jan 20, 2018 5:14 pm

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by SteveFrench » Sat Jan 20, 2018 5:23 pm

Stunning picture, but wondering if there's purpose/significance in having image reversed? Seems puzzling considering the title.

User avatar
Joe Stieber
Science Officer
Posts: 195
Joined: Tue Aug 18, 2009 1:41 pm
Location: Maple Shade, NJ

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by Joe Stieber » Sat Jan 20, 2018 8:23 pm

SteveFrench wrote:Stunning picture, but wondering if there's purpose/significance in having image reversed? Seems puzzling considering the title.
By “reversed,” I suppose you mean left-to-right. In that case, it’s because the picture was taken from the Southern Hemisphere. Up here in the USA at mid-northern latitudes, the horns (or cusps) of the moon were pointing to the upper-left vs. the upper-right in today’s APOD.

I’m wondering what happened to the star Iota Cap, which was prominent in some pictures I took of the crescent moon on January 18. But I don’t know the time the APOD was taken, and the moon moves fast enough that Iota might have been out of the frame compared to mine. The background sky is also a bit brighter in the APOD.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18759
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by neufer » Sat Jan 20, 2018 10:41 pm

Joe Stieber wrote:
SteveFrench wrote:
Stunning picture, but wondering if there's purpose/significance in having image reversed? Seems puzzling considering the title.
By “reversed,” I suppose you mean left-to-right. In that case, it’s because the picture was taken from the Southern Hemisphere. Up here in the USA at mid-northern latitudes, the horns (or cusps) of the moon were pointing to the upper-left vs. the upper-right in today’s APOD.

I’m wondering what happened to the star Iota Cap, which was prominent in some pictures I took of the crescent moon on January 18. But I don’t know the time the APOD was taken, and the moon moves fast enough that Iota might have been out of the frame compared to mine. The background sky is also a bit brighter in the APOD.
The Earth is 4 times the width of the Moon and hence 2º wide seen from the Moon.

That also means that besides moving ~0.5º per hour west to east vs-a-vs the stars
the Moon will be ~1º South of the stars compared to a Southern Hemisphere view.
Art Neuendorffer

heehaw

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by heehaw » Sat Jan 20, 2018 10:50 pm

"The Earth is 4 times the width of the Moon and hence 2º wide seen from the Moon." The astronauts were encased in space suits, but even so, I'm surprised at the (as far as I know) lack of quotes about the astonishing appearance of planet Earth overhead. Can anyone supply information on this?

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18759
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by neufer » Sun Jan 21, 2018 3:14 am

heehaw wrote:
"The Earth is 4 times the width of the Moon and hence 2º wide seen from the Moon." The astronauts were encased in space suits, but even so, I'm surprised at the (as far as I know) lack of quotes about the astonishing appearance of planet Earth overhead. Can anyone supply information on this?
For Apollo astronauts on the Moon the Earth was both high & fixed in the sky.

For Apollo astronauts orbiting the Moon the Earth was both low and therefore apparently much larger rising above the moonscape.
https://en.wikipedia.org/wiki/Earthrise wrote:

<<Earthrise is the name given to NASA image AS08-14-2383, taken by astronaut William Anders during the Apollo 8 mission, the first manned voyage to orbit the Moon. Initially, before Anders found a suitable 70 mm color film, mission commander Frank Borman took a black-and-white photograph of the scene, with the Earth's terminator touching the horizon. The land mass position and cloud patterns in this image are the same as those of the color photograph entitled Earthrise. The photograph was taken from lunar orbit on December 24, 1968, with a highly modified Hasselblad 500 EL with an electric drive. The camera had a simple sighting ring rather than the standard reflex viewfinder and was loaded with a 70 mm film magazine containing custom Ektachrome film developed by Kodak.
  • Anders: Oh my God! Look at that picture over there!
    There's the Earth coming up. Wow, is that pretty.


    Borman: Hey, don't take that, it's not scheduled. (joking)

    Anders: (laughs) You got a color film, Jim?
    Hand me that roll of color quick, would you...


    Lovell: Oh man, that's great!
Art Neuendorffer

joe burns

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by joe burns » Mon Jan 22, 2018 3:33 pm

Is this image reversed? A young crescent would be on the Eastern lLimb not the Western limb.

User avatar
geckzilla
Ocular Digitator
Posts: 9158
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA

Re: APOD: Old Moon in the New Moon's Arms (2018 Jan 20)

Post by geckzilla » Mon Jan 22, 2018 3:40 pm

joe burns wrote:Is this image reversed? A young crescent would be on the Eastern lLimb not the Western limb.
Check your location.
Just call me "geck" because "zilla" is like a last name.