astroavani

The Seeliger effect Generally, when you look at Saturn through a telescope before or after opposition, the rings look as bright as the planet's globe. For days at the time of the opposition, however, the rings suddenly intensify in apparent brightness, blinding the globe before returning to its normal appearance. German astronomer Hugo von Seeliger (1849-1924) noticed this change for the first time in 1887. Because of his pioneering research on its cause, which led him to conclude that Saturn's rings were composed of small particles, the effect was named in honor of that scientist. Two main physical processes lead to the Seeliger effect: shadow hiding and coherent backscattering. When we see Saturn directly illuminated by the Sun (as it is during opposition), the planet's shadow “hides” behind the globe, putting more surface of the ring in view. As a result, the rings appear to lighten. The same angle of direct illumination also causes the shadows of individual particles in the rings to temporarily disappear, improving the result. The Seeliger effect, which combined the enhancements of shadow hiding and coherent backscatter, makes Saturn's rings appear brighter the closer the planet is to the opposite side of the sun. The Seeliger effect, which combines the enhancements of shadow hiding and coherent backscatter, makes Saturn's rings appear brighter the closer the planet is to the side opposite the Sun, as in the top image compared to the bottom. Christopher Go But that is not all. Observations of the effect of the opposition on the Cassini spacecraft's Saturn rings, in orbit around the planet, reveal that "coherent backscattering" also contributes significantly to the phenomenon. This occurs when sunlight interacts with the collective particles in the planet's rings; the reflections of many irregular pieces of rock and dust combine to produce a single, more coherent (coherent) light. This light spreads back to our eyes and makes the rings appear lighter. In contrast, and in the days immediately following, we see the combination of these two mechanisms as a temporary increase in the overall illumination of the rings. The only way to fully appreciate the effect visually, however, is to monitor the planet and its rings during the days around that magical moment - weather permitting. Source: Astronomy; Stephen James O'Meara

A Cave in Marius HillsMost researchers agree that the Moon is about 4.5 billion years old, possibly about 50 million years younger than the rest of the solar system. One of the theories says that the moon was formed when another planet (about the size of Mars) struck the molten stone ball that was Earth at that time. Some of the remains of that collision were turned into space where they eventually reformulated as a solid mass - our current moon.Although this part of the Moon's history is generally accepted, other areas are still very uncertain. One is the question of when there was volcanic activity on the Moon, how long this activity lasted and how much there was. Early studies of lunar volcanic rocks were possible when samples were brought to Earth by astronauts during the Apollo missions from 1969 to 1972.Studies suggest that volcanic activity on the moon began soon after the formation of the moon, or about 0.5 billion years earlier than previously thought. Most of the volcanism on the Moon probably happened around 3.8 to 3.9 billion years ago, and mostly stopped about 3 billion years ago.In December 2009, the Kaguya spacecraft sent images of a large hole in a winding wave in the Marius Hills region, a volcanic area on the lunar side. Sinuous rails are formed in two different ways: as open lava canals and / or as lava tubes, many of which subsequently collapse. Because the Marius Hills well is in the middle of a winding rille, it probably represents a collapse in the roof of a lava tube. The well itself may have been caused by a meteorite impact that pierced through the roof of the lava tube.The Marius Hills well was discovered in images from the Japanese camera SELENE / Kaguya Terrain and Multiband Imager, and reported in Geophysical Research Letters. The Japanese team, led by Junichi Haruyama, performed multiple observations of the well using both the Terrain Camera and the Multiband Imager at resolutions up to 6 meters / pixel (see central photos). The LROC image (shown here at the top left) at 0.5 meters / pixel is the highest resolution image of the Marius Hills batch to date! The SELENE / Kaguya Terrain Camera team also made a film about the hole (https://www.lpi.usra.edu/lunar/lunar_flyovers/marius_hills/). The Marius Hills region was volcanically quite active in the past and contains numerous volcanic features including winding riles like those labeled Rilles A and B plus numerous hills that are actually domes and can be seen quite clearly in my photo.How and when did the well caves form? On Earth, volcanic pit craters are formed as the roof of a lava tube collapses, often while the magma is still flowing underground. The resulting aperture is often referred to as a skylight. Can we determine if the moon skylights formed during or after the lavas on the floor flow? Perhaps the best place to start looking for evidence is on the pit floor. If the skylight was formed long after the eruptions had ceased and the underground lava tubes were cold, you might find a chaotic pile of rubble on the floor. If the well collapsed into an active lava tube, you can find the smooth, frozen surface of the last lava that flowed through the tube.This well or skylight is intriguing because it suggests that many other lunar Rilles may also have wells or skylights formed through the collapse of the lava tube.Robert Zimmerman in this article; http://behindtheblack.com/behind-the-black/essays-and-commentaries/single-rope-techinque-on-the-moon/, makes some interesting assumptions about the depth of the well and the difficulty in exploring it in future missions.Lava tubes may be useful as sites for lunar bases (see a report by Fred Hörz of JSC here:http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1985lbsa.conf..405H&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf. The interior of lava tubes could protect human explorers from different aspects of the lunar environment, including cosmic rays, meteorite impacts, and extreme temperature differences between lunar day and night. Like caves on Earth, lunar caves, including lava tubes, have temperatures that are constant. Our human ancestors, who in a distant age inhabited caves to protect themselves at the dawn of civilization, will have known, their descendants doing the same in that silver star that illuminated the shadows and turned away the darkness and their deepest fears!Sources: KaKuya / Jaxa-Selene - LROC / NASA - Behind the Black / Robert Zimmerman - Lunar and Planetary Institute - Lava Tube / Friedrich HörzAdaptation and text: Avani Soares

So create courage and get to work!

I'm not entirely sure, but something around 1000X magnification. A correct calculation could be made, but I am making a rough estimate.

LOL, amazed because you liked it?

I had the opportunity to borrow a monochrome camera to do the tests I always wanted on the Moon.Below are the first results for colleagues to analyze.I realized from the outset the advantage of mono cameras for specific wavelengths since I normally use an ASI290MC to do all my captures. This is mainly explained by the fact that, without the layer matrix, a monochrome camera uses 100% of its pixels to perform the capture, while a color camera would use only 25% to capture on the IR 685 which was the filter used.Despite everything, due to the great fluctuation of my seeing, varying in a matter of a few minutes, I do not discard the advantages of a color camera for color captures, since while a mono camera would make only 1 film I can make at least about 4 with the colored one. This greatly increases the chance of catching a brief favorable moment that can save an entire section of photography.Moon on May 4, 2020.C14 Edge + ASI 178MM + IR pass 685Total of 2000 frames per photo with 350 stacking.

The planet Saturn is being recognized as the "moon king" of our solar system. Jupiter used to keep track of most of the moons that orbit around it. It has 79. But scientists in the United States have announced the discovery of 20 new moons around Saturn. This gives the planet a new total of 82 moons. The researchers made the discovery using the powerful Subaru telescope in Hawaii. They collected information over a period of several years. The team also used new computer models to identify moons and track activities in orbit. The discovery was announced in late September 2019 by the International Astronomical Union's Minor Planet Center. The center is responsible for identifying all the smallest planets in the world, comets and "natural outer satellites". The organization also measures the orbital movements of such objects. Researchers say the newly found moons are very small, measuring about five kilometers in diameter. The team has managed to discover them now because of the best technology that has become available in recent years. This includes more powerful telescopes and greater computing power. One of the newly identified moons orbits Saturn at a great distance, some 25 million kilometers from the planet. This is further away than any other moon on Saturn. Seventeen of the new moons orbit Saturn backwards. In other words, its movement is opposite to the rotation of the planet. The other three orbit in the same direction as the planet rotates. The researchers said that several moons appear to have been formed from parts of larger moons. These past moons probably split up into collisions with other moons or comets or asteroids. "These new moons show us that the solar system was a very chaotic place in the distant past, with objects flying all over the place," these moons are among the last remaining evidence of the formation of the solar system. All other objects were either pushed out or became parts of other planets.

Researchers from Canada have used computer models to show that our Solar System could have had an extra gas giant planet in the mix around 4 billion years ago – until Jupiter booted it out, that is. The idea that there were originally five gas giants – in addition to Jupiter, Saturn, Uranus, and Neptune – was first proposed back in 2011, to help explain why the Solar System currently looks the way it does. As it turns out, the orbit of Mars and Earth don't really make sense if there were only ever the planets we have today. But researchers haven't been able to explain until now what could have happened to that extra planet, with both Jupiter and Saturn named as potential culprits for doing the kicking out. "Our evidence points to Jupiter," said lead researcher Ryan Cloutier from the University of Toronto, who describes the whole thing as an "interplanetary chess game". The mystery lost planet in question is believed to have had the mass of an ice giant, which means that it was heavier than Saturn and Jupiter, and in the same class as Neptune and Uranus. So how exactly does a lighter planet suddenly kick an ice giant clear out of the Solar System? Planetary ejections generally happen as a result of a close planetary encounter - but not necessary a collision - which causes one of the objects to accelerate so rapidly that it's able to break free from the massive gravitational pull of the Sun and go slingshotting out into the galaxy, becoming what's known as a rogue planet. In this case, the ejection could be the result of Jupiter moving closer to the Sun from further out in the Solar System, affecting the orbit of other planets on its way. Earlier studies had struggled to work out exactly which of the remaining planets could have done this, but in the new research, the astronomers from the University of Toronto realised that up until now, no one had factored in the effect this encounter would have had on the moons orbiting the giant planets. So the team decided to look at the trajectories of Callisto and Iapetus – two of the regular moons orbiting Jupiter and Saturn respectively. Using computer models, they investigated the likelihood of the moons having the same orbit as they do today if they'd been involved in a mass planetary ejection 4 billion years ago. "Ultimately, we found that Jupiter is capable of ejecting the fifth giant planet while retaining a moon with the orbit of Callisto," said Cloutier. "On the other hand, it would have been very difficult for Saturn to do so because Iapetus would have been excessively unsettled, resulting in an orbit that is difficult to reconcile with its current trajectory." The computer model showed that there's about a 42 percent chance that Callisto would have its current orbit around Jupiter if it had been involved in the planetary ejection. The results have been published in The Astrophysical Journal. But to be clear, this doesn't mean that we have any evidence this interaction actually took place, or even that there was an extra planet in the Solar System in the first place. This is all based off computer models, and while they can explain the current state of the planets in our Solar System, they're not the only possibilities out there. "We do know that rogue planets roam the galaxy, and they were almost certainly ejected in this manner, so the idea of a lost solar system planet isn’t crazy," wrote astronomer Phil Plait for Discover back in 2011 when the missing planet hypothesis was first proposed. "But it’s only one possible scenario." Still, it's kind of cool to think that, somewhere out there in the galaxy, a frozen ice giant is roaming, a lost remnant from the formation of our Solar System.

A very interesting placement friend Maw!

Saturn is the sixth planet from the Sun and the second largest planet in our solar system. Adorned with a dazzling system of icy rings, Saturn is unique among the planets. It is not the only planet to have rings, but none are as spectacular or as complex as Saturn's. Like fellow gas giant Jupiter, Saturn is a massive ball made mostly of hydrogen and helium. Surrounded by more than 80 known moons, Saturn is home to some of the most fascinating landscapes in our solar system. From the jets of water that spray from Enceladus to the methane lakes on smoggy Titan, the Saturn system is a rich source of scientific discovery and still holds many mysteries. Saturn is a gas giant made up mostly of hydrogen and helium. Saturn's volume is greater than 760 Earths, and it is the second most massive planet in the solar system, about 95 times Earth's mass. The Ringed Planet is the least dense of all the planets, and is the only one less dense than water. If there were a bathtub big enough to hold it, Saturn would float. The yellow and gold bands seen in Saturn's atmosphere are the result of superfast winds in the upper atmosphere, which can reach up to 1,100 mph (1,800 km/h) around its equator, combined with heat rising from the planet's interior. Saturn rotates about once every 10.5 hours. This means that we, amateur astrophotographers, should not film it for more than 90 seconds, under penalty of possible details running out, the longest footage should use the derrotation technique. The planet's high-speed spin causes Saturn to bulge at its equator and flatten at its poles. The planet is around 75,000 miles (120,000 kilometers) across at its equator, and 68,000 miles (109,000 km) from pole to pole. Saturn's environment is not conducive to life as we know it. The temperatures, pressures and materials that characterize this planet are most likely too extreme and volatile for organisms to adapt to. While planet Saturn is an unlikely place for living things to take hold, the same is not true of some of its many moons. Satellites like Enceladus and Titan, home to internal oceans, could possibly support life. These are just some curiosities of the Lord of the Rings!

Tycho Crater is an one of the most prominent craters on the moon. It appears as a bright spot in the southern highlands with rays of bright material that stretch across much of the nearside. Its prominence is not due to its size: at 85 km in diameter, it's just one among thousands of this size or larger. What really makes Tycho stand out is its relative youth. It formed recently enough that its beautiful rays, material ejected during the impact event, are still visible as bright streaks. All craters start out looking like this after they form, but their rays gradually fade away as they sit on the surface, exposed to the space environment which over time darkens them until they fade into the background. How old is Tycho? Because the impact event scattered material to such great distances, it's thought that some of the samples at the Apollo 17 landing site originated at the Tycho impact site. These samples are impact melt glass, and radiometric age dating tells us that they formed 108 million years ago. So if these samples are truly from Tycho, the crater formed 108 million years ago as well. This may still seem old, but compared to the 3.9 billion-year age for many large lunar craters, Tycho is the new kid on the block. Directly sampling material from within the crater would help us learn more about not just when Tycho formed, but the ages of terrains on other planets throughout the solar system. Planetary surfaces are dated by counting the number of craters on the surface, and comparing that number to the number of craters that formed on a surface for which we know the age by actually sampling the rocks. The problem is, there aren't that many places for which we've sampled the rocks, and confirming the age of Tycho would help date younger surfaces, which are not well sampled. Tycho is also of great scientific interest because it is so well preserved, it is a great place to study the mechanics of how an impact crater forms. The Constellation site is on the floor of Tycho, near its central peak. The peak is thought to be material that has rebounded back up after being compressed in the impact, and though it's a peak now, it originated at greater depth than any other portion of the crater. The floor of the crater is covered in impact melt, rocks that were heated to such high temperatures during the impact event that they turned to liquid, and flowed across the floor.

Once again I managed to catch the storm near Saturn's north pole. This time it is much more noticeable on the IR 685. I have to check other color films to see if I didn't get something too because it doesn't show up.

As soon as interest in photography begins to awaken. After learning to like, get ready to invest a lot!

LOL, without exaggeration my friend Ruud.

Titan, a moon with lakes and beaches! Scientists suggest a new destination for beach holidays in the Solar System. Too bad it's not easy to get there. Researchers published in the journal Nature, the identification of a dark lake, surrounded by a lighter coastal region and a "beach" on the surface of Titan, Saturn's largest moon. The lake - shaped like a shoe sole - is the first extraterrestrial liquid body and probably contains hydrocarbons, simple compounds also common on Earth. "This is the first conclusive evidence of the presence of liquid hydrocarbons on Titan," according to the lead author of the article, Robert Brown, professor of planetary science at the Lunar and Planetary Laboratory (LPL) at the University of Arizona in Tucson. Instruments aboard NASA's Cassini orbiter around Saturn and its satellites, including Titan, since June 2004, reveal the presence of liquid ethane - an organic compound containing carbon - in an area roughly the same dimensions as Lake Ontario ( one of the Great Lakes between Canada and the United States) in the Southern Hemisphere of Titan. Similar dark regions have also been detected in the Northern Hemisphere, indicating that probably Titan's surface is dotted with hydrocarbon “seas”. Researchers confirmed the presence of liquid ethane from results obtained by the Visible and Infrared Mapping Spectrometer ( VIMS) on board Cassini, who detected hydrocarbon lines in these bands of the spectrum. Ethane is formed from the action of sunlight on the methane in Titan's atmosphere. The ethane in the atmosphere is believed to condense into clouds that precipitate in the form of rain. As it drains over Titan's surface, the rain makes its way forming currents that end up being dammed in real lakes of ethane. Titan has attracted the attention of astronomers thanks to its atmosphere formed by an orange mist, which extends 965 kilometers from its surface. Nitrogen is the dominant element, although there are traces of methane and other hydrocarbons, including propane. With a diameter of 5,150 km, Titan is larger than Mercury and only 25% smaller than Mars, making it the second largest moon in the Solar System, just after Ganymede, Jupiter's moon. Liquid ethane or methane was already suspected on Titan's surface. This discovery confirmed the idea that Titan has a "hydrological cycle" similar to that of Earth. But the liquid that forms clouds, rain and then evaporates again is not water, but methane and ethane, recalls the work's co-author, Christophe Sotin, planetary scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena , Calif., In addition to putting an end to debates about the existence of liquids on Titan, this discovery could alter the course of future missions. Both NASA and the European Space Agency (Esa) are considering returning to Titan; these new observations support the idea of sending a vehicle that lands on a lake - a floating probe - to take samples of its composition, says Ralph Lorenz, planetary scientist at the Laboratory of Applied Physics at Johns Hopkins University in Laurel, Maryland. The liquid pool, called Ontario Lacus, absorbs practically all the incident light which gives it a dark hue, according to Brown from LPL. The data also reveal that the lake's surface is calm, without ripples or waves, which for Brown is surprising. He and his team hoped to find waves caused by possible surface winds. There is little chance of life on Titan. “It's just a matter of fertile imagination,” says Jonathan Lunine, a professor of planetary science and physics at JPL, who did not participate in the study. "If a terrestrial organism is left on the surface of Titan, it will surely die." But, the probability of exotic forms of life in a liquid hydrocarbon environment is not ruled out. Confirmation of the presence of organic compounds and nitrogen means that Titan has a chemical composition very similar to that of the primitive Earth, when life began to develop. "These compounds form the basis for the future formation of more complex molecules," says Brown. The dominant idea is that the chemistry needed to create molecules with the capacity to replicate and store information - like DNA - did not develop on Titan, due to the extremely low temperatures (average of -181º C). The lack of liquid water on the surface - the main ingredient for the formation of life as we know it - is another reason that may have prevented the evolution of life on Titan, if it ever emerged. But Brown warns that volcanoes and other tectonic activities can add energy and even water to this mix. "Although nobody believes that much," says Brown, if life finds a way to develop on Titan, it will definitely be in a very different climate than ours.

For now everything is fine here friend Pete, the covid 19 is still taking a break in my region, but we are quarantined. I have taken the opportunity to take photos of the 3 planets but they are still very low so the quality is compromised.

As Jupiter goes up and getting better we can risk starting to photograph the satellites. All photos were taken separately, neither proportional size nor position was respected. Ganymedes the stain really seems to be albedo, but Callisto I have doubts. https://www.astrobin.com/full/18rk28/0/?nc=

My English sucks, and the Google translator does worse. Where you read 2 liters, you should read 2 degrees, and where you read the star, you should read ASTRO, a word that I believe does not exist in English or French.

Two photos taken at an interval of one lunar month with a difference of only 4% of the illuminated phase accurately demonstrate the importance of libration in lunar observation. With just another 2 liter in the south latitude, we can easily see the central peaks of the Hausen crater in the February photo that are not visible in the January photo. A good lunar observer or even a careful photographer will certainly not miss this opportunity. These little things make the Moon one of the most interesting stars in the solar system, just know what to look for! https://www.astrobin.com/full/0vuhvu/0/?nc=user

Mars, 2020-02-20 Mars this morning! It is already beginning to give enough details, if a sandstorm does not occur as in the last appearance, this will be the year of the red planet. For now we are only 5 "arc, still far from the 22" arc that we will have in the opposition.

Thanks Geoff!

That's the golden question friend Pete! Probably the APs of that time will be taking pictures of exoplanets, LOL.

Thanks my friend Peter!

Mars is gradually positioning itself favorably for photos, you can see several regions that can be bought with the projection of Virtual Planet Atlas. Color photo processing done to highlight the clouds present on the planet! https://www.astrobin.com/t7gfx8/

Wilhelm Lohrmann 1824 Sinus Medii original chart and the February 1, 2020 register by the Brazilian selenographer Avaní Soares! A nice comparison between early XIX century well drawn lunar features and details by Lohrmann and 200 years later, the expertise of Avaní and his incredible hi-res images! This clearly shows the importance of lunar visual observation and sketching and high-resolution lunar photography!!! An important point to observe on 1824 Lohrmann's charts are the gradual albedo markings, one of the interesting innovations at the time and certainly not an easy thing to accomplish, to properly measure and translate into a beautiful done engraving! Some interesting features, in the 200 years old Lohrmann chart, are absent. For example, the Rimae Triesnecker structure on the left side of crater. Although some albedo difference was noted by Lohrmann that vaguely follow this rimae path. Certainly, other craters and details are missing. Why? Well, that is the fascinating aspect of comparing a 200-year-old chart with an actual hi-res photography! Perhaps the original Lohman’s telescope aperture was not enough to observe some details, perhaps he has not the visual acuity to observe them or the Sun inclination was not the best at the moment of the observations... Anyway, it’s amazing what a 200-year-old chart reveal! Text and editing: Andrés de La Plaza https://www.astrobin.com/full/s7ixwk/0/?real=&mod=