Tuesday, July 31, 2018
What lies beneath the layered south pole of Mars? A recent measurement with ground-penetrating radar from ESA's Mars Express satellite has detected a bright reflection layer consistent with an underground lake of salty water. The reflection comes from about 1.5-km down but covers an area 200-km across. Liquid water evaporates quickly from the surface of Mars, but a briny confined lake, such as implied by the radar reflection, could last much longer and be a candidate to host life such as microbes. Pictured, an infrared, green, and blue image of the south pole of Mars taken by Mars Express in 2012 shows a complex mixture of layers of dirt, frozen carbon dioxide, and frozen water.
On July 28th, to see total lunar eclipse I just got near Mount Damavand - highest volcano in Asia - and took this shot! Different stages of totality can be seen in this photo sequence.
Monday, July 30, 2018
Moonrise doesn't usually look this interesting. For one thing, the full moon is not usually this dark -- but last Friday the moon rose here as it simultaneously passed through the shadow of the Earth. For another thing, the Moon does not usually look this red -- but last Friday it was slightly illuminated by red sunlight preferentially refracted through the Earth's atmosphere. Next, the Moon doesn't usually rise next to a planet, but since Mars was also coincidently nearly opposite the Sun, the red planet was visible to the full moon's upper right. Finally, from the vantage point of most people, the Moon does not usually rise over Rio de Janeiro in Brazil. Last Friday's sunset eclipse, however, specifically its remarkable Micro Blood Moon Total Lunar Eclipse, was captured from Rio's Botofogo Beach, along with an unusually large crowd of interested onlookers.
RED WORLDS – MOON AND MARS ALIGNED TOGETHER DURING TOTAL LUNAR ECLIPSE Taken by Miguel Claro on July 27, 2018 @ Campinho, Dark Sky Alqueva Reserve, Portugal
1 - Red Worlds – Moon and Mars Aligned Together During Total Lunar Eclipse
Only separated by approximately 6º apart, the red-orange planet Mars didn´t want to miss the “Red Celestial Party ” standing very close to the Moon during the longest Total Lunar Eclipse of the Century – 27th July 2018 – as seen from Dark Sky® Alqueva region in Portugal, this mosaic shows both in the same field of view. During a lunar eclipse, the moon passes through Earth’s shadow, giving the natural satellite a blood-red hue. With Mars making its closest approach in 15 years. The Red planet was also in opposition to the sun on this same night of the Lunar Eclipse, July 27, meaning being in opposite the sun in Earth’s sky, only 51 days before it passes through perihelion — its closest point relative to the sun in its orbit.
2 - Close-up View during Totality after the end of occultation of the star HD195157 in Capricornus
The image shows a close-up view of a red dark Moon taken with a telephoto lens during the longest Total Lunar Eclipse of the Century, on 27th July 2018, as seen from Dark Sky® Alqueva region in Portugal. During a lunar eclipse, the moon passes through Earth’s shadow, giving the natural satellite a blood-red hue. The image was capture few minutes after the end of occultation of the star HD195157 in Capricornus. With a visual magnitude of +8.93 it can be seen very close to the right limb of the moon (look at 3 o´clock).
We saw the eclipse at Hakos Farm in Namibia. The seeing was perfect. During totality the southern milkyway appeared bright right above us.
Sunday, July 29, 2018
.. 8pm ..
.. bastante nubladito ..
PARA VER EN HD ABRIR SIGUIENTE LINK
Saturday, July 28, 2018
Complete compilation of the Total Lunar Eclipse, 28th July 2018. Its been a mesmerising experience.
I did managed to get the nice clear turquoise shadings at the beginning of totality.
LUNAR ECLIPSE OVER THE CARAVANSARY Taken by Amirreza Kamkar on July 28, 2018 @ Deyr-e-Gachin caravansary-Tehran-Iran
Captured at Deyr-e-Gachin caravansary in Iran, the image shows the eclipsed Moon close to the central bulge of the Milky Way. Planet mars at its brightest in 15 years was another attraction in the sky just below the Moon.
it definitely wasnt great for photos, quite hazy and lots of blowing snow with winds around 25kts
Mars on top, Moon on the bottom
Danjon scale value: L=1 & L=2
Stack of 2 images
Canon 5d Mark IV + 24-70mm F/2.8
24mm, F/5 - 15 sec., ISO 8000
ONE NIGHT, ONE TELESCOPE, ONE CAMERA Image Credit & Copyright: Fernando Cabrerizo (Centro Astronomico de Tiedra)
Taken on the same night, from the same place, with the same telescope and camera, these postcards from our Solar System are shown at the same scale to provide an interesting comparison of apparent sizes. Spanning about half a degree in planet Earth's sky, the Moon is a stitched mosaic of six images. The others are the result of digitally stacked frames or simple single exposures, with the real distances to the objects indicated along the bottom of each insert. Most of the Solar System's planets with their brighter moons, and Pluto were captured during the telescopic expedition, but elusive Mercury was missed because of clouds near the horizon. The International Space Station was successfully hunted, though. The night was July 21st. Telescope and camera were located at the Centro Astronomico de Tiedra Observatory in Spain.
Friday, July 27, 2018
The partially eclipsed moon rise in the evening twilight over the radio telescope of Medicina in Italy.
I have observed many lunar eclipses, but on this very beautiful & darker totality was than many previous ones. weather was very warm & partly cloudy sky.
Total lunar eclipse of july the 27th, image taken in Gourdon (French riviera) The weather was not good enough for taking precise photos of the moon only, so we decided to compose the photo with children and accessories. Eos 5d mk4 - 70-200 at f8 - 4s - iso 800
IN LOVE WITH TOTAL LUNAR ECLIPSE, MILKYWAY AND MARS CONJUNCTION Taken by Bill Metallinos on July 27, 2018 @ Corfu, Greece
In love with Total Lunar Eclipse, Milkyway and Mars Conjunction
Night landscape above Lagoon Korission in Corfu island, a Natura 2.000 area with the Total Lunar Eclipse and the Mars on the left and the Glory of Milkyway during the Eclipse!
Sony a7sii, ef 16-35 Lii 2.8, iso1000, 5X30sec, traced and stacked
Not so good images because of cloudy sky from start eclipse to the end but at least i got something.
Very fortunate with the weather and the pristine skies which materialized a few hours before the onset of this evenings longest total solar eclipse of the 21st century.
Further details in relation to these images are available on my website at http://www.perseus.gr/Astro-Eclipses-2018-07-27.htm , http://www.perseus.gr/Astro-Eclipses-2018-07-27-Seq-1.htm and http://www.perseus.gr/Astro-Eclipses-2018-07-27-Seq-2.htm .
Saturn, as viewed by the Hubble Space Telescope on 6 June. Image: NASA, ESA, A. Simon (GSFC) and the OPAL Team, and J. DePasquale (STScI); Mars: NASA, ESA, and STScI
The Hubble Space Telescope has captured stunning new views of Mars and Saturn in June and July. Hubble captured Mars on 18 July when the red planet was at a distance of 59.4 million kilometres (36.9 million miles) from Earth. The image clearly shows the on-going global dust storm that is obscuring the surface. Mars reaches opposition, lined up with Earth and the Sun, on July 27 and will reach its point of closest approach to Earth on July 31, providing the best view of the red planet since 2003. Saturn was imaged on June 6 when the ringed world was about 2.2 billion kilometres (1.4 billion miles) from Earth. Saturn reached opposition on 27 June.
Mars, as seen by the Hubble Space Telescope on 18 July. Image: NASA, ESA, A. Simon (GSFC) and the OPAL Team, and J. DePasquale (STScI); Mars: NASA, ESA, and STSc
Look opposite the Sun in the sky tonight and you'll see Mars at its brightest. Also within days of its closest approach Mars rises at sunset, near its brightest and best for telescopic observers too, except for the dust storm still blanketing the Red Planet. These two Hubble Space Telescope images compare Mars' appearance near its 2016 and 2018 oppositions. In 2016 the martian atmosphere was clear. Captured just days ago, the 2018 image shows almost the same face of Mars. Surface features obscured by dust, the planet's cloud enshrouded south pole is tilted more toward the Sun. Increased heat in the southern hemisphere spring and summer likely triggers planet wide dust storms. Of course, if you look opposite the Sun in the sky tonight, you'll also see a Full Moon near Mars. Skygazers NOT located in North America could see the Red Planet near a Red Moon during a Total Lunar Eclipse.
Thursday, July 26, 2018
The view of Mars shown here was assembled from MOC daily global images obtained on May 12, 2003.
Credits: NASA/JPL/Malin Space Science Systems
A new paper published in Science this week suggests that liquid water may be sitting under a layer of ice at Mars' south pole.
The finding is based on data from the European Mars Express spacecraft, obtained by a radar instrument called MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding). The Italian Space Agency (ASI) led the development of the MARSIS radar. NASA provided half of the instrument, with management of the U.S. portion led by the agency's Jet Propulsion Laboratory in Pasadena, California.
The paper, authored by the Italian MARSIS team, outlines how a "bright spot" was detected in radar signals about 1 mile (about 1.5 kilometers) below the surface of the ice cap in the Planum Australe region. This strong radar reflection was interpreted by the study's authors as liquid water -- one of the most important ingredients for life in the Universe.
"The bright spot seen in the MARSIS data is an unusual feature and extremely intriguing," said Jim Green, NASA's chief scientist. "It definitely warrants further study. Additional lines of evidence should be pursued to test the interpretation.”
"We hope to use other instruments to study it further in the future,” Green added.
One of those instruments will be on Mars later this year. NASA's InSight lander will include a heat probe that will burrow down as far as 16 feet (5 meters) below the Martian surface. The probe, built by the German Aerospace Center (DLR), will provide crucial data on how much heat escapes the planet and where liquid water could exist near its surface.
"Follow the Water" has been one of the major goals of NASA's Mars program. Water is currently driving NASA's exploration into the outer solar system, where ocean worlds -- like Jupiter's moon Europa and Saturn's moon Enceladus -- hold the potential to support life. Even protoplanets like Ceres may explain how water is stored in rocky "buckets" that transport water across the solar system.
Jet Propulsion Laboratory, Pasadena, Calif.
NASA Headquarters, Washington
A radar instrument on one of the oldest operational Mars orbiters has discovered possible evidence of present-day liquid water on Mars.
Liquid water on Mars? Again? Yes, again. The announcement came at a press briefing held by the Italian Space Agency in Rome, concerning a paper published today in Science.
How is today's water-on-Mars hoopla different from all of the past announcements? In brief: the evidence is from a new instrument, examining a new location on Mars, and it's the first place we've seen evidence for a present-day body of water that is liquid and stays liquid. For years.
The Mars Express orbiter has used radar signals bounced through underground layers of ice to find evidence of a pond of water buried below the south polar cap. Find more information on this image here.
Context map: NASA / Viking; THEMIS background: NASA / JPL-Caltech / Arizona State Univ.; MARSIS data: ESA / NASA / JPL / ASI / Univ. Rome; R. Orosei et al 2018
The report comes from the European Space Agency's Mars Express, the second-oldest spacecraft still operating at Mars. It's best known for the beautiful color stereo images from its High Resolution Stereo Camera, but today's results come from a different instrument, the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS). To explain the water story, I'll need to explain the instrument.
MARSIS transmits radio waves at Mars using a pair of booms, each 20 meters long, which extend on each side of Mars Express. The radio waves bounce off of Mars, and MARSIS measures the time it takes for the waves to travel there and back. Naturally, MARSIS detects strong reflections from the planet’s surface.
But the long radio waves from the 40-meter antenna can actually penetrate as many as 5 kilometers into the Martian surface and reflect off of interesting things below. Subsurface boundaries between layers of different properties — boundaries between rock and soil, or rock and ice, or clean ice and dusty ice — can also serve as radio reflectors. So MARSIS may detect multiple echoes from each radio pulse. It pulses many times along its ground track, building up a 2-dimensional view of the subsurface called a "radargram."
The bulk of MARSIS's results from Mars Express's 15 years at Mars have detailed the interior structure of the planet’s polar layered deposits. Both poles have these deposits, which consist largely of dusty water ice, in layers — they have a stripy appearance when viewed with cameras from orbit. MARSIS's radar sounding has traced those layers below the surface and mapped the sharp boundary of the base of the deposits at each pole, sensing the rocky surface of the planet buried beneath kilometers of ice. The MARSIS team first reported on their studies of Planum Australe — the south polar layered deposits — in 2008, noting that MARSIS could detect reflections from as much as 3,000 meters beneath the surface — very deep.
The ExoMars Trace Gas Orbiter captured this view of part of the south polar ice cap on Mars on May 13, 2018.
ESA / Roscosmos / CaSSIS , CC BY-SA 3.0 IGO
More recently, the MARSIS team picked a region where the surface appearance of the south polar layered deposits was especially bland, to try to study the base of the deposits in more detail. (If the surface is bland, it should be easier to see interesting things happening below.) MARSIS studied this region intensely from May 29, 2012, to December 27, 2015, collecting 29 crisscrossing radargrams.
In most places, the scientists described the bottom-most reflection on the radargrams as "weak and diffuse," but in a few places, they found it to be crisp and bright, indicating a very strong contrast between the layered deposits and whatever underlies them. In one particular location, about 20 kilometers wide, where many radargrams crossed, they kept hitting an especially strong and bright reflective boundary at about 1,500 meters beneath the surface.
An unusual, contained, 20-kilometer-wide spot of very strong radar contrast suggests an unusual material that is very different from the ice above it or the rock below it. It has consistently been detected over a period of three years. An unusual material located at the base of an ice sheet: Could it be a long-lived lake, like subglacial lakes on Earth?
Not so fast. The temperature is a challenge. It's pretty straightforward physics to predict the temperature at the base of the southern polar layered deposits. That predicted temperature is −68°C. Neither on Earth, nor on Mars, can water exist as a liquid at such a low temperature. Not without help, anyway.
But help for liquid water may exist down there. On Earth, sub-ice lakes exist at temperatures as low as −13°C. The freezing point of the water in lakes under ice in Antarctica is depressed by the presence of large amounts of salt (much more salt than is present in Earth's oceans). Mars has salts of sodium, magnesium, and calcium that — if concentrated enough — can depress the freezing point of water to as low as −74°C. Perchlorates — salts discovered by the Phoenix lander and observed also by Curiosity — are especially good at helping water remain liquid at cold temperatures. So it is physically possible that a very, very, very salty lake could exist beneath Mars' southern polar cap.
Mars Express has used radar signals bounced through underground layers of ice to identify a pond of water buried below the surface. This image shows an example radar profile for one of 29 orbits over the 200 x 200 km study region in the south polar region of Mars. The bright horizontal feature at the top corresponds to the icy surface of Mars. Layers of ice and dust under the south pole are seen to a depth of about 1.5 km. Below is a base layer that in some areas is even brighter than the surface reflections. The brightest reflections from the base layer – close to the center of this image – are centered around 193°E / 81°S in all intersecting orbits, outlining a well-defined, 20 km wide subsurface anomaly that is interpreted as a pond of liquid water.
ESA / NASA / JPL / ASI / Univ. Rome; R. Orosei et al. 2018
Okay, it's possible. But is it probable? The answer: yes! In fact, according to Roberto Orosei (National Institute of Astrophysics, Italy) and colleagues, a sub-ice briny lake (or layer of very sludgy, liquid-water-rich sediment) is the most likely explanation for this unusual reflective spot!! That's not quite strong enough evidence to constitute scientific proof for a hard-bitten, skeptical scientist such as myself, but if you'd like to imagine sending submersible spacecraft into an actual present-day sub-glacial liquid water lake on Mars, you have my blessing.
What can we do to confirm that such a lake exists? Higher-resolution data would help. MARSIS's radar spots span about 5 kilometers, so they barely resolve the 20-kilometer width of this putative lake. Future missions capable of better detail could more precisely map its contours and how they relate to the shape of the hidden rocky surface and the icy layers above.
If MARSIS has discovered a 20-kilometer-wide patch of liquid water, which is close to the limit of its detection resolution, there's every reason to believe there could be more such patches, too small for MARSIS to definitively resolve. If we get that higher-resolution view, it's possible we could discover lots and lots of briny spots deep underneath the Martian south polar cap.