* Astronomy

September 2008 Release to the Planetary Data System
HiRISE has just released hundreds of new images as part of its obligation to the Planetary Data System, covering orbit ranges 8200 through 9299.

Eroded Layered Deposits on Floor of Large Crater (PSP_008200_1555)	Persistent Northern Plains Ice Deposit (PSP_008200_2475)	Rayed Crater in Isidis Region (PSP_008201_1980)	Seasonal Frost on Dunes (PSP_008201_2580)
Sublimation Spots on Dunes (PSP_008203_2570)	Polar Crater with Summer Ice (PSP_008204_2440)	Faulted Layered Deposits in an Impact Crater in Meridiani Planum (PSP_008205_1880)	Crater with Exposed Layers (PSP_008206_1620)
Small Sinuous Channel in Tempe Fossae (PSP_008207_2250)	Awakening Dunes (PSP_008208_2600)	Knobby Terrain in Northern Arcadia Region (PSP_008210_2415)	Very Recent Small Rayed Crater in Elysium Region (PSP_008213_1965)
Periglacial Landscape in Northern Utopia Region (PSP_008214_2285)	Compositional Stratigraphy in Nili Fossae (PSP_008215_2015)	Periglacial Landscape in the Northern Plains (PSP_008216_2325)	Mid-Latitude Terrain West of Hellas Region (PSP_008217_1485)

New images for 3 September 2008

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Defrosted Margin of the North Polar Erg (PSP_009396_2590) This image shows a traverse across a section of the North Polar erg, a vast sea of sand that surrounds the polar cap.	Ius Chasmas Floor (PSP_009368_1720) Ius Chasma is located in the western region of Valles Marineris, the solar systems largest canyon.	Dust Devils Make Their Marks in Gusev Crater (PSP_009319_1650) Dust devils are actually giant convective vortices that form as a result of atmospheric vertical instability.
Evolution of North Polar Dunes (PSP_009233_2535) This small unnamed crater is adjacent to the North Polar Erg and contains a fascinating dune field.	Deeply Incised Gullies on Massif Slope in Nereidum Montes (PSP_009156_1335) These gullies are in the Nereidum Montes near the large Argyre Basin in the southern hemisphere.

New images for 27 August 2008

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Chloride Salt Deposits within a Channel in Terra Sirenum (PSP_009318_1465) Salt deposits are key targets in the search for ancient life on Mars, because they represent places where bodies of liquid water may have ponded and evaporated.	Structure of the North Polar Layered Deposits (PSP_009293_2645) The polar layered deposits on Mars are thought contain a record of global climate changes, similar to ice ages on Earth.	Relatively Recent Slope Streak Started from Dust Devil (PSP_009192_1890) Dark slope streaks are visible in many places on the Martian surface, often where the dust cover is thick.
Layered Deposits within Unnamed Crater in Arabia Terra (PSP_009180_1840) Arabia Terra is an area of Mars that has an abundance of layered deposits within impact craters.	Long Shadows at Ariadnes Colles (PSP_009161_1450) Winter solstice occurs in the shortest sol of the year, when the Sun travels the lowest in the Martian sky, making shadows appear very long.	Rock Outcrops in Southern Mid-Latitude Crater (PSP_009151_1465) This image captures a diverse range of rocks on the crater floor, with some units appearing rich in boulders.
Inverted Riverbed in Gale Crater (PSP_009149_1750) With an average vertical thickness of almost 4 km, the Gale Crater layered deposits are twice as thick as the layers exposed along the Grand Canyon on Earth.	Crater Bound Dunes (PSP_009087_2550) This region experiences a variety of winds that blow from various directions during different seasons and times of day, and the winds are also affected by the topography of the crater itself.

New images for 20 August 2008

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Cratered Cones in Isidis Planitia (PSP_009177_1985) The cones occur over a wide area and are commonly aligned in chains, like those here.	Fresh Double-Layered Ejecta Crater (PSP_009160_2350) The semi-circular feature that parallels the crater rim is a terrace that probably formed as part of the crater wall collapsed into the center.	Gullies and Bedrock Exposures in Impact Crater Wall (PSP_009155_1480) Some of the gully channels are very sharp, indicating that they have not been modified much since they formed.
Mineralogical Diversity in Nili Fossae (PSP_009138_2025) In the Nili Fossae region, the spectrometers have found remarkable diversity in surface composition.	Eroding Dunes in Chasma Boreale (PSP_009114_2645) In a process that is not yet completely understood, sheets of saltating sand grains organise themselves into sand dunes, visible in this image as the dark features.