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Airbus A400M Atlas

The Airbus A400M Atlas is a European four-engine turboprop military transport aircraft. It was designed by Airbus Military, now Airbus Defence and Space, as a tactical airlifter with strategic capabilities to replace older transport aircraft, such as the Transall C-160 and the Lockheed C-130 Hercules. The A400M is sized between the C-130 and the Boeing C-17 Globemaster III. It can carry heavier loads than the C-130 and can use rough landing strips. In addition to its transport capabilities, the A400M can perform aerial refueling and medical evacuation when fitted with appropriate equipment.

The A400M's maiden flight took place on 11 December 2009 from Seville Airport, Spain. Between 2009 and 2010, the A400M faced cancellation as a result of development programme delays and cost overruns; however, the customer nations chose to maintain their support for the project. A total of 174 A400M aircraft had been ordered by eight nations by July 2011. In March 2013, the A400M received European Aviation Safety Agency (EASA) certification and the first aircraft was delivered to the French Air Force in August 2013.

Origins
The project has its origins in the Future International Military Airlifter (FIMA) group, established in 1982 as a joint venture between Aérospatiale, British Aerospace (BAe), Lockheed, and Messerschmitt-Bölkow-Blohm (MBB) with the goal of developing a replacement for both the C-130 Hercules and Transall C-160. Varying requirements and the complications of international politics meant that progress on the initiative was slow. In 1989, Lockheed decided to withdraw from the grouping. Lockheed independently developed an upgraded Hercules, the C-130J Super Hercules. With the addition of Alenia of Italy and CASA of Spain, the FIMA group became Euroflag.

Project management evaluated twin and quad turbofan engine configurations, a quad propfan configuration, and a quad turboprop configuration, eventually settling on the turboprop option. Since no existing turboprop engine in the western world was powerful enough to reach the projected cruise speed of Mach 0.72, a new engine design was required. Originally, the SNECMA M138 turboprop, based on the M88 turbofan core was selected, but this powerplant was found to be incapable of satisfying the requirements. In April 2002, Airbus Military issued a new request for proposal (RFP), which Pratt & Whitney Canada with the PW180 and Europrop International answered. In May 2003, Airbus Military selected the Europrop TP400-D6. United Technologies alleged that the selection was a result of political interference.

A Europrop partner executive said in April 2003 that Airbus was close to selecting the P&WC offer, claiming it was more than €400 million (US$436.7 million) cheaper than Europrop's bid. As the original deadline for the engine decision passed, Airbus CEO Noel Forgeard said P&WC's bid was nearly 20 percent less expensive and declared that "As of today Pratt and Whitney is the winner without doubt, a much lower offer could make us change our minds.", inviting Europrop to revise its offering, which it reportedly reduced in price by 10 or 20 percent. A later report described the revised bid as exceeding P&WC's bid by €120 million.

The original partner nations were France, Germany, Italy, Spain, the United Kingdom, Turkey, Belgium, and Luxembourg. These nations decided to charge the Organisation for Joint Armament Cooperation (OCCAR) with the management of the acquisition of the A400M. Following the withdrawal of Italy and revision of procurement totals, the revised requirement was for 180 aircraft. The first flight was forecast to occur in 2008 and the first delivery in 2009. In April 2005, South Africa joined the programme, with the Denel Saab Aerostructures receiving a contract for fuselage components. Malaysia is the second country outside Europe to be involved. Malaysia through CTRM is responsible for manufacturing composite aero components for the aircraft.

The A400M is positioned as an intermediate size and range between the Lockheed C-130 and the Boeing C-17, carrying cargo too large or too heavy for the C-130, while able to use rough landing strips.

Delays and problems
In January 2009, EADS announced that the first delivery was postponed from 2009 until at least 2012, and indicated that it wanted to renegotiate. EADS maintained the first deliveries would begin three years after the first flight. In January 2009, Financial Times Deutschland reported that the A400M was overweight by 12 tons and may not meet a key performance requirement, the ability to airlift 32 tons. Sources told FTD that it could only lift 29 tons, insufficient to carry an infantry fighting vehicle like the Puma. In response to the report, the chief of the German Air Force stated: "That is a disastrous development," and could delay deliveries to the German Air Force (Luftwaffe) until 2014. The Initial Operational Capability (IOC) for the Luftwaffe was later delayed and alternatives, such as a higher integration of European airlift capabilities, were studied.

On 29 March 2009, Airbus CEO Tom Enders told Der Spiegel that the programme may be abandoned without changes. OCCAR reminded participating countries that they could terminate the contract before 31 March 2009. In April 2009, the South African Air Force announced that it was considering alternatives to the A400M due to delays and increased cost. On 5 November 2009, South Africa announced the order's cancellation. On 12 June, The New York Times reported that Germany and France had delayed a decision whether to cancel their orders for six months while the UK planned to decide in late June. The NYT also quoted a report to the French Senate from February 2009, noting: "the A400M is €5 billion over budget, 3 to 4 years behind schedule, [and] aerospace experts estimate it is also costing Airbus between €1 billion and €1.5 billion a year."

In 2009, Airbus acknowledged that the programme was expected to lose at least €2.4 billion and could not break even without export sales. A PricewaterhouseCoopers audit projected that it would run €11.2 billion over budget, and that corrective measures would result in an overrun of €7.6 billion. On 24 July 2009, the seven European nations announced that the programme would proceed and formed a joint procurement agency to renegotiate the contract. On 9 December 2009, the Financial Times reported that Airbus requested an additional €5 billion subsidy. In January 2010, Airbus repeated that the A400M may be scrapped, costing it €5.7 billion unless €5.3 billion was added by partner governments, delays had already increased its budget by 25%. Airbus executives reportedly regarded the A400M as competing for resources with the A380 and A350 XWB programmes.

In June 2009, Lockheed Martin said that both the UK and France had requested details on the C-130J as an alternative to the A400M.

In November 2010, Belgium, Britain, France, Germany, Luxembourg, Spain and Turkey finalised the contract and agreed to lend Airbus Military €1.5 billion. The programme was then at least three years behind schedule. The UK reduced its order from 25 to 22 aircraft and Germany from 60 to 53, decreasing the total order from 180 to 170.

In 2013, France's budget for 50 aircraft was €8.9bn (~US$11.7bn) at a unit cost of €152.4m (~US$200m), or €178m (~US$235m) including development costs. The 2013 French White Paper on Defence and National Security cut the tactical transport aircraft requirement from 70 to 50. As the A400M was unable to perform helicopter in-flight refuelling, France announced in 2016 that it would purchase four C-130Js. In July 2016, French aerospace laboratory ONERA confirmed successful wind tunnel trials of a 36.5 m (120 ft) hose and drogue configuration that permits helicopter refuelling. Prior tests found instability in the intended 24 m (80 ft) hose due to vortices generated by the spoilers, deployed to achieve 108-130 kt air speed.

In April 2016, production faults affecting 14 propeller gearboxes (PGBs) produced by Italian supplier Avio Aero were discovered. The issue, involving a heat treatment process that weakened the ring gear, affected no other PGBs; the units involved needed changing. Airbus noted: "pending full replacement of the batch, any aircraft can continue to fly with no more than one affected propeller gearbox installed and is subject to continuing inspections." Another PGB issue involved input pinion plug cracking, which could release small metallic particles into the oil system, which is safeguarded by a magnetic sensor. Only engines 1 and 3, which have propellers that rotate to the right, were affected. The European Aviation Safety Agency (EASA) issued an Airworthiness Directive mandating immediate on-wing inspection, followed by replacement if evidence of damage is found. On 27 April 2016, Airbus warned there may be a substantial PGB repair cost. An interim PGB fix was certified in July 2016, greatly extending inspection intervals.

In May 2016, Airbus confirmed that a cracking behaviour identified during quality control checks in 2011 was found in a French A400M's fuselage part. Not impacting safety, it could be repaired during regular maintenance/upgrade schedules. The aluminium-zinc alloy, known as 7000 series, was used in several central frames. Its chemistry, along with environmental conditions, led to crack propagation. The alloy was excluded from future aircraft. A retrofit to remove it from early A400Ms was considered, which could take up to seven months.

On 29 May 2016, Enders conceded in an interview published in Bild am Sonntag that some of the "massive problems" of the A400M were of Airbus' own making: "We underestimated the engine problems...Airbus had let itself be persuaded by some well-known European leaders into using an engine made by an inexperienced consortium." Furthermore, it had assumed full responsibility for the engine. On 27 July 2016, Airbus confirmed that it took a $1 billion charge over delivery issues and export prospects. Enders stated: "Industrial efficiency and the step-wise introduction of the A400M's military functionalities are still lagging behind schedule and remain challenging."

Flight testing
Before the first flight, required airborne test time on the Europrop TP400 engine was gained using a C-130 testbed aircraft, which first flew on 17 December 2008. On 11 December 2009, the A400M's maiden flight was carried out from Seville. In April 2010, the second A400M made its first flight. In July 2010, the third A400M took to the air, at which point the fleet had flown 400 hours over more than 100 flights. In July 2010, the A400M passed ultimate-load testing of the wing. In October 2010, Airbus announced the start of refuelling and air-drop tests. By October 2010, the A400M had flown 672 hours of the 2,700 hours expected to reach certification. In November 2010, the first paratroop jumps were performed. Enders and A400M project manager Bruno Delannoy were among the skydivers.

In late 2010, simulated icing tests were performed on the MSN1 flight test aircraft using devices installed on the wing's leading edges. These revealed an aerodynamic issue causing horizontal tail buffeting, resolved via a six-week retrofit to install anti-icing equipment fed with bleed air. Production aircraft are similarly fitted. Winter tests were done in Kiruna, Sweden in February 2011. In March 2012, high altitude start and landing tests were performed at La Paz at 4,061.5 m (13,325 ft) and Cochabamba at 2,548 m (8,360 feet) in Bolivia.

By April 2011, a total of 1,400 flight hours over 450 flights had been achieved. In May 2011, the TP400-D6 engine received certification from the EASA. In May 2011, the A400M fleet had totaled 1,600 hours over 500 flights. By September 2011, the total increased to 2,100 hours and 684 flights. Due to a gearbox problem, an A400M was shown on static display instead of a flight demonstration at the 2011 Paris Air Show. By October 2011, the total flight hours had reached 2,380 over 784 flights.

In May 2012, the MSN2 flight test aircraft was due to spend a week conducting unpaved runway trials on a grass strip at Cottbus-Drewitz Airport in Germany. Testing was cut short on 23 May, when, during a rejected takeoff test, the left side main wheels broke through the runway surface. Airbus Military stated that it found the aircraft's behaviour was "excellent". The undamaged aircraft returned to Toulouse.

At the 2012 Royal International Air Tattoo, the aircraft was officially named "Atlas"

In March 2013, the A400M was granted type certification by the EASA, clearing its entry to service.

Production and delivery
Assembly of the first A400M began at the Seville plant of EADS Spain in early 2007. Major assemblies built at other facilities abroad were brought to the Seville facility by Airbus Beluga transporters. In February 2008, four Europrop TP400-D6 flight test engines were delivered for the first A400M. Static structural testing of a test airframe began in March 2008 in Spain. By 2010, Airbus planned to manufacture 30 aircraft per year. The Turkish partner, Turkish Aerospace Industries, delivered the first A400M component to Bremen in 2007.

The first flight, originally scheduled for early 2008, was postponed due to delays and financial pressures. EADS announced in January 2008 that engine issues had been responsible for the delay. The rescheduled first flight, set for July 2008, was again postponed. Civil certification under EASA CS-25 was followed by certification for military uses. In June 2008, the A400M was rolled out in Seville at an event presided by King Juan Carlos I of Spain.

On 12 January 2011, serial production began. In August 2013, the first A400M was delivered to the French Air Force. It was formally handed over during a ceremony in September 2013. In August 2013, the first Turkish A400M conducted its maiden flight from Seville. In March 2015, Malaysia received its first A400M.

In May 2015, it was revealed that the member nations had created a Programme Monitoring Team (PMT) to review and monitor progress in the A400M's development and production. The PMT inspects the final assembly line in Seville and other production sites. Early conclusions observed that Airbus lacked an integrated approach to production, development and retrofits, treating these as separate programmes.

On 9 May 2015, an A400M crashed in Seville on its first test flight. Germany, Malaysia, Turkey and UK suspended flights during the investigation. Initial focus was on whether the crash was caused by new fuel supply management software for trimming the fuel tanks to enable certain manoeuvres; Airbus issued an update instructing operators to inspect all Engine Control Units (ECUs). A key scenario examined by investigators is that the torque calibration parameter data was accidentally wiped on three engines during software installation, preventing FADEC operations. On 3 June 2015, Airbus announced that investigators had confirmed "that engines one, two and three experienced power frozen after lift-off and did not respond to the crew's attempts to control the power setting in the normal way."

On 11 June 2015, Spain's Ministry of Defence announced that prototypes could restart test flights and that further permits could be granted soon. The RAF lifted its suspension on A400M flights on 16 June 2015, followed the next day by the Turkish Air Force. On 19 June 2015, deliveries restarted. In June 2016, the French Air Force accepted its ninth A400M, the first capable of conducting tactical tasks such as airdropping supplies. The revised standard includes the addition of cockpit armour and defensive aids system equipment, plus clearance to transfer and receive fuel in-flight.

Design

The Airbus A400M provides substantial improvements to payload, range, internal volume and operational capacity over the Transall C-160 and Lockheed C-130 that it replaces or augments. It can carry up to 37 MT over 2000 nmi. The cargo box is 17.71 m long excluding ramp, 4.00 m wide, and 3.85 m high (or 4.00 m aft of the wing). and can be configured to transport cargo, military personnel, drop paratroops, conduct medical evacuations or carry out aerial refuelling. It can operate out of short, soft landing strips and fly long-range cargo. A typical cargo load might include six Land Rovers and their trailers, or two light armoured vehicles, or a dump truck and excavator, or a Patriot missile system, or a Puma or Cougar helicopter, or a truck and 25-ton trailer.

It features a fly-by-wire flight control system with sidestick controllers and flight envelope protection. Like other Airbus aircraft, the A400M has a full glass cockpit. Most systems are loosely based on those of the A380, but modified for the military mission. The hydraulic system has dual 207 bar (3,000 psi) channels powering the primary and secondary flight-control actuators, landing gear, wheel brakes, cargo door and optional hose-and-drogue refuelling system. As with the A380, there is no third hydraulic system. Instead, there are two electrical systems. One is a set of dual-channel electrically powered hydraulic actuators, the other an array of electrically/hydraulically powered hybrid actuators. The dissimilar redundancy provides more protection against battle damage.

More than 30 percent of the airplane's structure is made of composite materials. The 42.4 m span wing is primarily made of carbon fibre reinforced plastic components, including the wing spars, the 19 m long, 12 – thick wingskins, and other parts. The wing weighs about 6500 kg, and it can carry and lift up to 25000 kg of fuel. It has an aspect ratio of 8.1, a wide chord of 5.6 m, and a sweep angle of 15 degrees at 25 percent mean aerodynamic chord.

The A400M has a T-tail empennage. Its vertical stabilizer is 8.02 m tall. The horizontal stabilizer spans 19.03 m, with a sweep of 32.5 degrees.

The Ratier-Figeac FH385 propellers turn counterclockwise and the FH386 clockwise. The eight-bladed scimitar propellers are made from a woven composite material. It is powered by four Europrop TP400-D6 engines rated at 8,250 kW (11,000 hp) each. The TP400-D6 engine is the most powerful turboprop engine in the West to enter operational use.

The pair of propellers on each wing turn in opposite directions, with the tips of the propellers advancing from above towards the midpoint between the two engines. This is in contrast to the overwhelming majority of multi-engine propeller driven aircraft where all propellers turn in the same direction. The counter-rotation is achieved by the use of a gearbox fitted to two of the engines, and only the propeller turns in the opposite direction. All four engines are identical and turn in the same direction. This eliminates the need to have two different "handed" engines on stock for the same aircraft, simplifying maintenance and supply costs. This configuration, dubbed down between engines (DBE), allows it to produce more lift and lessens the torque and prop wash on each wing. It also reduces yaw in the event of an outboard engine failure. Due to these benefits, the vertical stabilizer can be reduced by 17 percent in size, while the size of the horizontal stabilizer can be shrunk by 8 percent.

A forward-looking infrared enhanced vision system (EVS) camera provides an enhanced terrain view in low-visibility conditions. The EVS imagery is displayed on the HUD for low altitude flying, demonstrating its value for flying tactical missions at night or in cloud. EADS and Thales provides the new Multi-Colour Infrared Alerting Sensor (MIRAS) missile warning sensor for the A400M.

The A400M has a removable refuelling probe mounted above the cockpit, allowing it to receive fuel from drogue-equipped tankers. Optionally, the receiving probe can be replaced with a fuselage-mounted UARRSI receptacle for receiving fuel from boom equipped tankers. It can act as a tanker when fitted with two wing mounted hose and drogue under-wing refuelling pods or a centre-line Hose and Drum unit. The refuelling pods can transfer fuel to other aircraft at a rate of 2640 lb/min.

The A400M features deployable baffles in front of the rear side doors, intended to give paratroops time to get clear of the aircraft before they are hit by the slipstream.

Operational history

On 29 December 2013, the French Air Force performed the A400M's first operational mission: an aircraft flew to Mali in support of Operation Serval.

On 10 September 2015, the RAF was declared the A400M fleet leader in terms of flying hours, with 900 hours flown over 300 sorties, achieved by a fleet of four aircraft. Sqn. Ldr. Glen Willcox of the RAF's Heavy Aircraft Test Squadron confirmed that reliability levels were high for an aircraft so early in its career, and that night vision goggle trials, hot and cold soaking, noise characterization tests and the first tie-down schemes for cargo had already been completed. In March 2015, the RAF's first operational mission occurred, flying cargo to RAF Akrotiri, Cyprus.

In September and October 2017, A400Ms from France, Germany and the UK participated in the disaster relief operations following Hurricane Irma in the Caribbean, delivering a Puma helicopter, food, water and other aid supply, and evacuating stranded people.

In July 2018, the German Luftwaffe used an A400M in combat conditions for the first time, transporting 75 soldiers from Wunstorf to Mazar-i-Sharif. German Air Force Inspector Ingo Gerhartz called this a "milestone" because it was the first such mission in an active war zone and showed that the armoring kit was fully functional.

In September 2018, the French Air and Space Force announced that they had logged 10,000 flying hours with their fleet of 14 A400Ms, mostly flying supply missions for Operation Barkhane.

The German government had planned to sell the last 13 A400Ms out of its order of 53 aircraft but failed to attract any buyers. Instead, the government decided to employ them in service. During a visit to the Wunstorf Air Base in January 2019, the German Minister of Defence Ursula von der Leyen announced that the 13 A400Ms will be used to form a multinational airlift wing. Due to a lack of space at Wunstorf and for greater flexibility, the future air wing will be based at Lechfeld Air Base in southern Germany.

In 2019, a German A400M tanker replaced the Airbus A310 MRTT deployed to Muwaffaq Salti Air Base in Jordan, to refuel allied aircraft as part of the German intervention against ISIL.

In August 2021, a total of 25 A400Ms were deployed by Belgium, France, Germany, Spain, Turkey and the UK to assist in the Kabul Airport evacuations. German A400Ms evacuated 5,347 people over the course of 35 flights.

Exports

 * Chile: In July 2005, the Chilean Air Force signed a Memorandum of understanding for three aircraft, but no order was placed. Chile began talks on buying the Brazilian Embraer KC-390.
 * Czech Republic: In February 2017, the Czech Ministries of Defence stated they were interested in a joint lease of A400Ms from Germany.
 * Hungary: In September 2020, Hungary was named as the first partner of the Multinational Air Transport Unit to be established at Lechfeld Air Base, with 10 A400Ms contracted to Germany.
 * Indonesia: In January 2017, Indonesia approved the acquisition of five A400Ms to boost Indonesia's military airlift capabilities. In March 2017, a letter of intent with Airbus was signed by Pelita Air Services, representing a consortium of Indonesian aviation companies. In March 2018, the Indonesian Air Force and state entity Indonesia Trading Company (ITC) announced they were considering ordering two A400Ms, which would be crewed by the Indonesian Air Force and act in an air freight role helping to balance the prices of goods across the archipelago. The parties were interested in the aircraft's ability to operate from rough landing strips, where a normal air freighter could not, as well as the possibility of industrial offsets. In November 2021, Airbus confirmed that the Indonesian Ministry of Defense had signed a deal with Airbus for two A400Ms, with an option, in the form of a letter of intent, for four additional aircraft. In December 2022, Airbus announced that the contract has been finalised, the first delivery is expected in 2026.
 * Kazakhstan: In September 2021, Kazakhstan signed an agreement with Airbus to buy two A400Ms for the Kazakh Air Defense Forces. On 5 April 2024, the first aircraft was rolled out at the A400M Final Assembly building in Seville. It is expected to be delivered to Kazakhstan before 2025.
 * Malaysia: In December 2005, the Royal Malaysian Air Force ordered four A400Ms to supplement its fleet of C-130 Hercules.
 * South Africa: In December 2004, South Africa announced it would purchase eight A400Ms at a cost of approximately €837 million, with the nation joining the Airbus Military team as an industrial partner. Deliveries were expected from 2010 to 2012. In 2009, South Africa cancelled all eight aircraft, citing increasing costs. In November 2011, Airbus Military reached an agreement to refund pre-delivery payments worth €837 million to Armscor.
 * South Korea: In February 2019, South Korea's Defense Acquisition Program Administration (DAPA) confirmed a proposal from Spain to swap an undetermined number of KAI T-50 Golden Eagles and KAI KT-1 Woongbi trainers for A400M airlifters.

Variants

 * A400M Grizzly
 * Five prototype and development aircraft, a sixth aircraft was cancelled.

 * A400M-180 Atlas
 * Production variant

Accidents
An A400M crashed on 9 May 2015, when aircraft MSN23, on its first test flight crashed shortly after take-off from San Pablo Airport in Seville, Spain, killing four Spanish Airbus crew and seriously injuring two others. Once airborne, the crew contacted air traffic controllers just before the crash about a technical failure, before colliding with an electricity pylon while attempting an emergency landing. The crash was attributed to the FADEC system being unable to read engine sensors properly due to an accidental file-wipe, resulting in three of its four engines remaining in "idle" mode during takeoff.

title: Airbus A400M Atlas


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Bangor-on-Dee

Bangor-on-Dee (Bangor-is-y-coed or standardised Bangor Is-coed ) is a village and community in Wrexham County Borough, Wales, on the banks of the River Dee. Until 1974 it was in the exclave of Flintshire known as the Maelor Saesneg, and from 1974 to 1996 in the county of Clwyd.

The community had a population of 1,110 at the 2011 Census.

Etymology
The anglicised name refers to the village's proximity to the River Dee. However, the older Welsh name, Bangor-is-y-Coed (or Bangor Is-Coed) literally means "Bangor" (a settlement with a wattle enclosure) "below the wood/trees". This form was first recorded in 1699, while an alternative name of the parish, "Bangor Monachorum" ("Bangor of the monks"), was first recorded in 1677.

History
A monastery was established at Bangor in about AD 560 by Saint Dunod (or Dunawd) and was an important religious centre in the 5th and 6th centuries. The monastery was destroyed in about 613 by the Anglo-Saxon king Æthelfrith of Northumbria after he defeated the Welsh armies at the Battle of Chester, which probably took place near Bangor-on-Dee; a number of the monks then transferred to Bardsey Island and appear among lists of saints. Before the battle, monks from the monastery had fasted for three days and then climbed a hill to witness the fight and pray for the success of the Welsh; they were massacred on the orders of Æthelfrith. The scholar Bede wrote that 1200 monks were slaughtered and only 50 escaped. Other accounts are very different in terms of the numbers killed and the date: the Anglo-Saxon Chronicle, for example, states that 200 priests were slain at Chester in 607. More than a millennium later, the massacre was recounted in a poem entitled "The Monks of Bangor's March" by Walter Scott, and put to music by Ludwig van Beethoven. Today no trace of the monastery remains and even its site is uncertain; it is possible that all the buildings, including the church, were built of wattle and daub.

The settlement at Bangor is likely to have continued after the destruction of the monastery, although it was not mentioned in the Domesday Book, and it was an important site for pilgrims. A village was certainly in existence by 1300, when the present church of Saint Dunawd is believed to have been built. By the late 1690s, the historian Edward Lhuyd recorded that the village still had only 26 houses, but by the end of the 19th century it had significantly expanded, including a free school, a coaching inn, a shop, further houses and a brewery.

The Bangor-on-Dee Bridge, a five-arched stone arch bridge across the River Dee, dates its reconstruction to 1658 and it is believed to have been reconstructed to the designs of Inigo Jones and replaced an older medieval bridge. A 1903 suspension bridge by David Rowell & Co. is nearby at Pickhill Meadows.

Transport

Bangor had a station on the Cambrian Railways' Wrexham to Ellesmere line which crossed the River Dee via an iron bridge to the north of the village. This line was opened in 1895 and ran through an entirely rural area. The line closed for passenger services in 1962.

Recreation
South-west of the village there is Bangor-on-Dee racecourse, a National Hunt racecourse. There are also two pubs, a basketball court and river activities such as fishing and rafting.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Bangor-on-Dee


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Shipston-on-Stour

Shipston-on-Stour is a town and civil parish in the Stratford-on-Avon District in southern Warwickshire, England. It is located on the banks of the River Stour, 15 km south-southeast of Stratford-upon-Avon, 10 miles (16 km) north-northwest of Chipping Norton, 22 km south of Warwick and 14.5 miles (23 km) west of Banbury. In the 2021 census, Shipston-on-Stour had a population of 5,849.

This area is sometimes termed the Vale of Red Horse, close to the Oxfordshire and Gloucestershire borders.

Etymology linked to sheep and wool trade
In the 8th century, the toponym was Scepwaeisctune, Old English for Sheep-wash-Town. It had a sheep marketplace for many centuries. The name evolved through Scepwestun in the 11th century, Sipestone, Sepwestun and Schipton in the 13th century and Sepestonon-Sture in the 14th century.

Church (vestry) administration, township and parish formation
It was a township in the parish of Tredington until 1720: when they were separated by a Local Act of the 6th year of George I. The town proved prosperous and generous to its church community: the Church of England parish church of Saint Edmund has a 15th-century tower. The Gothic Revival architect G.E. Street designed the rebuilding of the rest of the church in 1855. The tower had a ring of five bells until 1695 when they were recast and rehung as a ring of six. Since then all the bells have been recast and rehung from time to time, notably in 1754 and by John Taylor & Co. in 1979.

A staging post for stagecoaches and regional market
Shipston is on the A3400 (formerly part of the A34) between Stratford-upon-Avon and Oxford; it was from the 1600s to 1800s a staging place for stagecoaches. There are former coaching inns, such as the Coach and Horses, in the High Street, which has many listed buildings.

From 1836, agricultural produce and manufactured goods were brought by a branch line from the horse-drawn Stratford and Moreton Tramway, which had been built ten years before to link Moreton-in-Marsh with Stratford on Avon. In 1889 the Great Western Railway upgraded the line to allow the operation of steam trains from Moreton to Shipston. Passenger services to the town's railway station were withdrawn in 1929 and goods services ceased in 1960.

Early Victorian times
The town's first library and reading room were founded in 1837. Manufacture of shag fabric for deep-pile carpets was for some decades an important business, but by 1848 the town had little manufacture or commerce even though it had more than 1800 residents. Worcester Cathedral owned the manorial rights for centuries, and even in the 1840s held a court annually, at which a town constable was appointed. Powers of the short-lived county debt court, established in 1847, extended over Shipston's civil registration district (established 1837). In that era the market was on Saturday and fairs in April, June, August and October. The rectory had Tidmington annexed and received net income of £700. The patrons were Worcester Cathedral and Jesus College, Oxford, the former presenting (appointing the priest) to every third vacancy. The church had extra seats, a gallery, erected in 1790. Baptists, the Society of Friends, and Wesleyans each had a place of worship; and at Foxcote, in the parish, was a Roman Catholic chapel. A National school was endowed with about £130 per annum; and "various small bequests" were distributed among the poor.

Poor law union and rural district
Shipston poor law union (c.1830–1894) administered those functions in 37 parishes or places: 20 in Warwickshire, 13 in Gloucestershire, and 4 in Worcestershire; across in the 1840s a population of 19,685 people.

From 1894, until 1974, the offices and Council meetings of Shipston-on-Stour Rural District were in Shipston.

County exclave
Shipston was in an exclave of Worcestershire (as part of Oswaldslow hundred) until 1931, when it was transferred to Warwickshire.

Amenities
The Sports Club has football, cricket, bowls, tennis and angling clubs. Shipston First Scout Group has Beaver (ages 6–8), Cub (ages 8–10½) and Scout (ages 10½–14) sections. Shipston on Stour Rugby Football Club currently plays in the Midlands 3 West (South) league. Shipston has a brass band.

Shipston has a small museum located off Telegraph Street. The museum was set up, and is run by local people. It is stocked with artefacts and memorabilia relating to the town and the surrounding villages.

Public services
The two schools serving the town are Shipston Primary School, and Shipston High School. The town also has a library, operated by the county council.

There is a small NHS community hospital serving the town; the Ellen Badger Hospital.

The Warwickshire Fire and Rescue Service operate a retained fire station in Shipston-on-Stour.

Transport
The A3400 road runs through Shipston, and links it with Stratford-upon-Avon to the north-west, and to Chipping Norton and Oxford to the south-east. The A429 road passes to the west, using part of the historic Fosse Way, which connect Shipston with Warwick to the north, and Tewkesbury to the south-west.

The nearest railway station to Shipston today is Moreton-in-Marsh railway station on the Cotswold Line around 6 mi to the south. Shipston once had its own railway station at the end of a branch line, which had its passenger services withdrawn in 1929, and goods services in 1960.

Media
Local TV coverage is provided by BBC West Midlands and ITV Central. Television signals are received from either the Lark Stoke or Sutton Coldfield TV transmitters.

Local radio stations are BBC CWR, Capital Mid-Counties (formerly 102 Touch FM), Heart West Midlands, Free Radio Coventry & Warwickshire, Fresh (Coventry & Warwickshire), and Radio Warneford which broadcast to patients at the Ellen Badger Hospital in the town.

The town is served by these local newspapers, Evesham Journal and Coventry Telegraph.

Governance
Shipton-on-Stour is a civil parish which falls within areas of Stratford-on-Avon District Council and Warwickshire County Council, each responsible for different aspects of local government. The lowest tier of local government is Shipston Town Council, a parish council, which has 13 elected councillors.

Shipston is within the Parliamentary constituency of Stratford-on-Avon

Notable people
Notable people connected with Shipston include:
 * Cy Endfield (1914–1995) American-born director of such notable films as Hell Drivers and Zulu; he had emigrated to England and lived and died in Shipston after being blacklisted as a Communist during the McCarthy era.
 * Francis J. Haverfield (1860–1919) - 19th-century archaeologist, born in Shipston.
 * Tessa Jowell (1947–2018) - former Labour politician and government minister, lived at Shipston-on-Stour at the time of her death in 2018.
 * Joseph Mawle (1974) film and TV actor, born in Oxford, but grew up in Shipston.
 * Richard Morant (1945–2011) - film and TV actor, born in Shipston.
 * Edward William Mountford (1855–1908) architect, born in Shipston.

Cultural references
Robin Gibb of the Bee Gees mentioned Shipston in his song "Cold Be My Days", which contains the lyrics "Cold be my days in Shipston-on-Stour": The song was recorded in 1970, but not released until 2015 for the unfinished album Sing Slowly Sisters. He stated in a BBC Radio 4 interview in May 2007 that this relates to his youthful experiences, riding horses with his brother Barry.

title: Shipston-on-Stour


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Thrips

Thrips (order Thysanoptera) are minute (mostly 1 mm long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Entomologists have described approximately 7,700 species. They fly only weakly and their feathery wings are unsuitable for conventional flight; instead, thrips exploit an unusual mechanism, clap and fling, to create lift using an unsteady circulation pattern with transient vortices near the wings. Thrips are a functionally diverse group, with nearly half of the known species being fungivorous. A small proportion of species of thrips are serious pests of commercially important crops. Some of these serve as vectors for over 20 viruses that cause plant disease, especially the Tospoviruses. Many flower-dwelling species bring benefits as pollinators, with some predatory thrips feeding on small insects or mites. In the right conditions, such as in greenhouses, invasive species can exponentially increase in population size and form large swarms because of a lack of natural predators coupled with their ability to reproduce asexually, making them destructive to crops. Due to their cryptic nature, thrips may aggregate in household objects such as furniture, bedding and computer monitors – in the latter case by forcing their way in between the LCD and its glass covering. Their identification to species by standard morphological characteristics is often challenging.

Naming and etymology
The first recorded mention of thrips dates from the 17th century, and a sketch was made by Philippo Bonanni, a Catholic priest, in 1691. Swedish entomologist Baron Charles De Geer described two species in the genus Physapus in 1744, and Linnaeus in 1746 added a third species and named this group of insects Thrips. In 1836 the Irish entomologist Alexander Henry Haliday described 41 species in 11 genera and proposed the order name of Thysanoptera. The first monograph on the group was published in 1895 by Heinrich Uzel, who is regarded by Fedor et al. as the father of Thysanoptera studies.

The generic and English name thrips is a direct transliteration of the  Ancient Greek word θρίψ, thrips, meaning "woodworm". Like some other animal-names (such as sheep, deer, and moose) in English the word "thrips" expresses both the singular and plural, so there may be many thrips or a single thrips. Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, storm bugs, corn fleas, corn flies, corn lice, freckle bugs, harvest bugs, and physopods. The older group name "physopoda" references the bladder-like tips to the tarsi of the legs. The name of the order, Thysanoptera, is constructed from the ancient Greek words θύσανος, thysanos, "tassel or fringe", and πτερόν, pteron, "wing", with reference to the insects' fringed wings.

Morphology

Thrips are small hemimetabolic insects with a distinctive cigar-shaped body plan. They are elongated with transversely constricted bodies. They range in size from 0.5 to 14 mm in length for the larger predatory thrips, but most thrips are about 1 mm in length. Flight-capable thrips have two similar, strap-like pairs of wings with a fringe of bristles. The wings are folded back over the body at rest. Their legs usually end in two tarsal segments with a bladder-like structure known as an "arolium" at the pretarsus. This structure can be everted by means of hemolymph pressure, enabling the insect to walk on vertical surfaces. They have compound eyes consisting of a small number of ommatidia and three ocelli or simple eyes on the head.

Thrips have asymmetrical mouthparts unique to the group. Unlike the Hemiptera (true bugs), the right mandible of thrips is reduced and vestigial – and in some species completely absent. The left mandible is used briefly to cut into the food plant; saliva is injected and the maxillary stylets, which form a tube, are then inserted and the semi-digested food pumped from ruptured cells. This process leaves cells destroyed or collapsed, and a distinctive silvery or bronze scarring on the surfaces of the stems or leaves where the thrips have fed.

Thysanoptera is divided into two suborders, Terebrantia and Tubulifera; these can be distinguished by morphological, behavioral, and developmental characteristics. Tubulifera consists of a single family, Phlaeothripidae; members can be identified by their characteristic tube-shaped apical abdominal segment, egg-laying atop the surface of leaves, and three "pupal" stages. In the Phlaeothripidae, the males are often larger than females and a range of sizes may be found within a population. The largest recorded phlaeothripid species is about 14 mm long. Females of the eight families of the Terebrantia all possess the eponymous saw-like (see terebra) ovipositor on the anteapical abdominal segment, lay eggs singly within plant tissue, and have two "pupal" stages. In most Terebrantia, the males are smaller than females. The family Uzelothripidae has a single species and it is unique in having a whip-like terminal antennal segment.

Evolution
The earliest fossils of thrips date back to the Permian Permothrips longipennis, although it probably not a member of this group. By the Early Cretaceous, true thrips became much more abundant. The extant family Merothripidae most resembles these ancestral Thysanoptera, and is probably basal to the order. There are currently over six thousand species of thrips recognized, grouped into 777 extant and sixty fossil genera. Some thrips were pollinators of the Ginkgoales as early as 110-105 Mya, in the Cretaceous. Cenomanithrips primus, Didymothrips abdominalis and Parallelothrips separatus are known from Myanmar amber of the Cenomanian age.

Phylogeny
Thrips are generally considered to be the sister group to Hemiptera (bugs).

The phylogeny of thrips families has been little studied. A preliminary analysis in 2013 of 37 species using 3 genes, as well as a phylogeny based on ribosomal DNA and three proteins in 2012, supports the monophyly of the two suborders, Tubulifera and Terebrantia. In Terebrantia, Melanothripidae may be sister to all other families, but other relationships remain unclear. In Tubulifera, the Phlaeothripidae and its subfamily Idolothripinae are monophyletic. The two largest thrips subfamilies, Phlaeothripinae and Thripinae, are paraphyletic and need further work to determine their structure. The internal relationships from these analyses are shown in the cladogram.

Taxonomy
The following families are currently (2013) recognized:

 * Suborder Terebrantia Frankadult.jpg vespiformis'' (Aeolothripidae), a widely distributed tropical species]]
 * Adiheterothripidae Shumsher, 1946 (11 genera)
 * Aeolothripidae Uzel, 1895 (29 genera) – banded thrips and broad-winged thrips
 * Fauriellidae Priesner, 1949 (four genera)
 * †Hemithripidae Bagnall, 1923 (one fossil genus, Hemithrips with 15 species)
 * Heterothripidae Bagnall, 1912 (seven genera, restricted to the New World)
 * †Jezzinothripidae zur Strassen, 1973 (included by some authors in Merothripidae)
 * †Karataothripidae Sharov, 1972 (one fossil species, Karataothrips jurassicus)
 * Melanthripidae Bagnall, 1913 (six genera of flower feeders)
 * Merothripidae Hood, 1914 (five genera, mostly Neotropical and feeding on dry-wood fungi) – large-legged thrips
 * †Scudderothripidae zur Strassen, 1973 (included by some authors in Stenurothripidae)
 * Thripidae Stephens, 1829 (292 genera in four subfamilies, flower living) – common thrips
 * †Triassothripidae Grimaldi & Shmakov, 2004 (two fossil genera)
 * Uzelothripidae Hood, 1952 (one species, Uzelothrips scabrosus)

 * Suborder Tubulifera
 * Phlaeothripidae Uzel, 1895 (447 genera in two subfamilies, fungal hyphae and spore feeders)

The identification of thrips to species is challenging as types are maintained as slide preparations of varying quality over time. There is also considerable variability leading to many species being misidentified. Molecular sequence based approaches have increasingly been applied to their identification.

Feeding
Thrips are believed to have descended from a fungus-feeding ancestor during the Mesozoic, and many groups still feed upon and inadvertently redistribute fungal spores. These live among leaf litter or on dead wood and are important members of the ecosystem, their diet often being supplemented with pollen. Other species are primitively eusocial and form plant galls and still others are predatory on mites and other thrips. Two species of Aulacothrips, A. tenuis and A. levinotus, have been found to be ectoparasites on aetalionid and membracid plant-hoppers in Brazil. Akainothrips francisi of Australia is a parasite within the colonies of another thrips species Dunatothrips aneurae that makes silken nests or domiciles on Acacia trees. A number of thrips in the subfamily Phlaeothripinae that specialize on Acacia hosts produce silk with which they glue together phyllodes to form domiciles inside which their semi-social colonies live.

Mirothrips arbiter has been found in paper wasp nests in Brazil. The eggs of the hosts including Mischocyttarus atramentarius, Mischocyttarus cassununga and Polistes versicolor are eaten by the thrips. Thrips, especially in the family Aeolothripidae, are also predators, and are considered beneficial in the management of pests like the codling moths.

Most research has focused on thrips species that feed on economically significant crops. Some species are predatory, but most of them feed on pollen and the chloroplasts harvested from the outer layer of plant epidermal and mesophyll cells. They prefer tender parts of the plant, such as buds, flowers and new leaves. Besides feeding on plant tissues, the common blossom thrips feeds on pollen grains and on the eggs of mites. When the larva supplements its diet in this way, its development time and mortality is reduced, and adult females that consume mite eggs increase their fecundity and longevity.

Pollination

Some flower-feeding thrips pollinate the flowers they are feeding on, and some authors suspect that they may have been among the first insects to evolve a pollinating relationship with their host plants. Scirtothrips dorsalis carries pollen of commercially important chili peppers. Darwin found that thrips could not be kept out by any netting when he conducted experiments by keeping away larger pollinators. Thrips setipennis is the sole pollinator of Wilkiea huegeliana, a small, unisexual annually flowering tree or shrub in the rainforests of eastern Australia. T. setipennis serves as an obligate pollinator for other Australian rainforest plant species, including Myrsine howittiana and M. variabilis. The genus Cycadothrips is a specialist pollinator of cycads, the cones of which are adapted for pollination by small insects. Thrips are likewise the primary pollinators of heathers in the family Ericaceae, and play a significant role in the pollination of pointleaf manzanita. Electron microscopy has shown thrips carrying pollen grains adhering to their backs, and their fringed wings are perfectly capable of allowing them to fly from plant to plant.

Damage to plants
Thrips can cause damage during feeding. This impact may fall across a broad selection of prey items, as there is considerable breadth in host affinity across the order, and even within a species, varying degrees of fidelity to a host. Family Thripidae in particular is notorious for members with broad host ranges, and the majority of pest thrips come from this family. For example, Thrips tabaci damages crops of onions, potatoes, tobacco, and cotton.

Some species of thrips create galls, almost always in leaf tissue. These may occur as curls, rolls or folds, or as alterations to the expansion of tissues causing distortion to leaf blades. More complex examples cause rosettes, pouches and horns. Most of these species occur in the tropics and sub-tropics, and the structures of the galls are diagnostic of the species involved. A radiation of thrips species seems to have taken place on Acacia trees in Australia; some of these species cause galls in the petioles, sometimes fixing two leaf stalks together, while other species live in every available crevice in the bark. In Casuarina in the same country, some species have invaded stems, creating long-lasting woody galls.

Social behaviour
While poorly documented, chemical communication is believed to be important to the group. Anal secretions are produced in the hindgut, and released along the posterior setae as predator deterrents In Australia, aggregations of male common blossom thrips have been observed on the petals of Hibiscus rosa-sinensis and Gossypium hirsutum; females were attracted to these groups so it seems likely that the males were producing pheromones.

In the phlaeothripids that feed on fungi, males compete to protect and mate with females, and then defend the egg-mass. Males fight by flicking their rivals away with their abdomen, and may kill with their foretarsal teeth. Small males may sneak in to mate while the larger males are busy fighting. In the Merothripidae and in the Aeolothripidae, males are again polymorphic with large and small forms, and probably also compete for mates, so the strategy may well be ancestral among the Thysanoptera.

Many thrips form galls on plants when feeding or laying their eggs. Some of the gall-forming Phlaeothripidae, such as genera Kladothrips and Oncothrips, form eusocial groups similar to ant colonies, with reproductive queens and nonreproductive soldier castes.

Flight
Most insects create lift by the stiff-winged mechanism of insect flight with steady state aerodynamics; this creates a leading edge vortex continuously as the wing moves. The feathery wings of thrips, however, generate lift by clap and fling, a mechanism discovered by the Danish zoologist Torkel Weis-Fogh in 1973. In the clap part of the cycle, the wings approach each other over the insect's back, creating a circulation of air which sets up vortices and generates useful forces on the wings. The leading edges of the wings touch, and the wings rotate around their leading edges, bringing them together in the "clap". The wings close, expelling air from between them, giving more useful thrust. The wings rotate around their trailing edges to begin the "fling", creating useful forces. The leading edges move apart, making air rush in between them and setting up new vortices, generating more force on the wings. The trailing edge vortices, however, cancel each other out with opposing flows. Weis-Fogh suggested that this cancellation might help the circulation of air to grow more rapidly, by shutting down the Wagner effect which would otherwise counteract the growth of the circulation.

Apart from active flight, thrips, even wingless ones, can also be picked up by winds and transferred long distances. During warm and humid weather, adults may climb to the tips of plants to leap and catch air current. Wind-aided dispersal of species has been recorded over 1600 km of sea between Australia and South Island of New Zealand. It has been suggested that some bird species may also be involved in the dispersal of thrips. Thrips are picked up along with grass in the nests of birds and can be transported by the birds.

A hazard of flight for very small insects such as thrips is the possibility of being trapped by water. Thrips have non-wetting bodies and have the ability to ascend a meniscus by arching their bodies and working their way head-first and upwards along the water surface in order to escape.

Life cycle

Thrips lay extremely small eggs, about 0.2 mm long. Females of the suborder Terebrantia cut slits in plant tissue with their ovipositor, and insert their eggs, one per slit. Females of the suborder Tubulifera lay their eggs singly or in small groups on the outside surfaces of plants.

Thrips are hemimetabolous, metamorphosing gradually to the adult form. The first two instars, called larvae or nymphs, are like small wingless adults (often confused with springtails) without genitalia; these feed on plant tissue. In the Terebrantia, the third and fourth instars, and in the Tubulifera also a fifth instar, are non-feeding resting stages similar to pupae: in these stages, the body's organs are reshaped, and wing-buds and genitalia are formed. The larvae of some species produce silk from the terminal abdominal segment which is used to line the cell or form a cocoon within which they pupate. The adult stage can be reached in around 8–15 days; adults can live for around 45 days. Adults have both winged and wingless forms; in the grass thrips Anaphothrips obscurus, for example, the winged form makes up 90% of the population in spring (in temperate zones), while the wingless form makes up 98% of the population late in the summer. Thrips can survive the winter as adults or through egg or pupal diapause.

Thrips are haplodiploid with haploid males (from unfertilised eggs, as in Hymenoptera) and diploid females capable of parthenogenesis (reproducing without fertilisation), many species using arrhenotoky, a few using thelytoky. In Pezothrips kellyanus females hatch from larger eggs than males, possibly because they are more likely to be fertilized. The sex-determining bacterial endosymbiont Wolbachia is a factor that affects the reproductive mode. Several normally bisexual species have become established in the United States with only females present.

As pests

Many thrips are pests of commercial crops due to the damage they cause by feeding on developing flowers or vegetables, causing discoloration, deformities, and reduced marketability of the crop. Some thrips serve as vectors for plant diseases, such as tospoviruses. Over 20 plant-infecting viruses are known to be transmitted by thrips, but perversely, less than a dozen of the described species are known to vector tospoviruses. These enveloped viruses are considered among some of the most damaging of emerging plant pathogens around the world, with those vector species having an outsized impact on human agriculture. Virus members include the tomato spotted wilt virus and the impatiens necrotic spot viruses. The western flower thrips, Frankliniella occidentalis, has spread until it now has a worldwide distribution, and is the primary vector of plant diseases caused by tospoviruses. Other viruses that they spread include the genera Ilarvirus, (Alpha|Beta|Gamma)carmovirus, Sobemovirus and Machlomovirus. Their small size and predisposition towards enclosed places makes them difficult to detect by phytosanitary inspection, while their eggs, laid inside plant tissue, are well-protected from pesticide sprays. When coupled with the increasing globalization of trade and the growth of greenhouse agriculture, thrips, unsurprisingly, are among the fastest growing group of invasive species in the world. Examples include F. occidentalis, Thrips simplex, and Thrips palmi.

Flower-feeding thrips are routinely attracted to bright floral colors (including white, blue, and especially yellow), and will land and attempt to feed. It is not uncommon for some species (e.g., Frankliniella tritici and Limothrips cerealium) to "bite" humans under such circumstances. Although no species feed on blood and no known animal disease is transmitted by thrips, some skin irritation has been described.

Management
Thrips develop resistance to insecticides easily and there is constant research on how to control them. This makes thrips ideal as models for testing the effectiveness of new pesticides and methods.

Due to their small sizes and high rates of reproduction, thrips are difficult to control using classical biological control. Suitable predators must be small and slender enough to penetrate the crevices where thrips hide while feeding, and they must also prey extensively on eggs and larvae to be effective. Only two families of parasitoid Hymenoptera parasitize eggs and larvae, the Eulophidae and the Trichogrammatidae. Other biocontrol agents of adults and larvae include anthocorid bugs of genus Orius, and phytoseiid mites. Biological insecticides such as the fungi Beauveria bassiana and Verticillium lecanii can kill thrips at all life-cycle stages. Insecticidal soap spray is effective against thrips. It is commercially available or can be made of certain types of household soap. Scientists in Japan report that significant reductions in larva and adult melon thrips occur when plants are illuminated with red light.

title: Thrips


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Speckle imaging

Speckle imaging comprises a range of high-resolution astronomical imaging techniques based on the analysis of large numbers of short exposures that freeze the variation of atmospheric turbulence. They can be divided into the shift-and-add ("image stacking") method and the speckle interferometry methods. These techniques can dramatically increase the resolution of ground-based telescopes, but are limited to bright targets.

Explanation
The principle of all the techniques is to take very short exposure images of astronomical targets, and then process those so as to remove the effects of astronomical seeing. Use of these techniques led to a number of discoveries, including thousands of binary stars that would otherwise appear as a single star to a visual observer working with a similar-sized telescope, and the first images of sunspot-like phenomena on other stars. Many of the techniques remain in wide use today, notably when imaging relatively bright targets.

The resolution of a telescope is limited by the size of the main mirror, due to the effects of Fraunhofer diffraction. This results in images of distant objects being spread out to a small spot known as the Airy disk. A group of objects whose images are closer together than this limit appear as a single object. Thus larger telescopes can image not only dimmer objects (because they collect more light), but resolve objects that are closer together as well.

This improvement of resolution breaks down due to the practical limits imposed by the atmosphere, whose random nature disrupts the single spot of the Airy disk into a pattern of similarly-sized spots scattered over a much larger area (see the adjacent image of a binary). For typical seeing, the practical resolution limits are at mirror sizes much less than the mechanical limits for the size of mirrors, namely at a mirror diameter equal to the astronomical seeing parameter r0 – about 20 cm in diameter for observations with visible light under good conditions. For many years, telescope performance was limited by this effect, until the introduction of speckle interferometry and adaptive optics provided a means of removing this limitation.

Speckle imaging recreates the original image through image processing techniques. The key to the technique, found by the American astronomer David L. Fried in 1966, was to take very fast images in which case the atmosphere is effectively "frozen" in place. At infrared wavelengths, coherence times τ0 are on the order of 100 ms, but for the visible region they drop to as little as 10 ms. When exposure times are shorter than τ0, the movement of the atmosphere is too sluggish to have an effect; the speckles recorded in the image are a snapshot of the atmospheric seeing at that instant. Coherence time τ0 = r0/v is a function of wavelength, because r0 is a function of wavelength.

The downside of the technique is that taking images at this short an exposure is difficult, and if the object is too dim, not enough light will be captured to make analysis possible. Early uses of the technique in the early 1970s were made on a limited scale using photographic techniques, but since photographic film captures only about 7% of the incoming light, only the brightest of objects could be viewed in this way. The introduction of the CCD into astronomy, which captures more than 70% of the light, lowered the bar on practical applications by an order of magnitude, and today the technique is widely used on bright astronomical objects (e.g. stars and star systems).

Many of the simpler speckle imaging methods have multiple names, largely from amateur astronomers re-inventing existing speckle imaging techniques and giving them new names.

Another use of the technique is in industry. By shining a laser (whose smooth wavefront is an excellent simulation of the light from a distant star) on a surface, the resulting speckle pattern can be processed to give detailed images of flaws in the material.

Shift-and-add method

The shift-and-add method (more recently "image-stacking" method) is a form of speckle imaging commonly used for obtaining high quality images from a number of short exposures with varying image shifts. It has been used in astronomy for several decades, and is the basis for the image stabilisation feature on some cameras. The short exposure images are aligned by using the brightest speckle and averaged to give a single output image.

The method involves calculation of the differential shifts of the images. This is easily accomplished in astronomical images since they can be aligned with the stars. Once the images are aligned they are averaged together. It is a basic principle of statistics that variation in a sample can be reduced by averaging together the individual values. In fact, when using an average, the signal-to-noise ratio should be increased by a factor of the square root of the number of images. A number of software packages exist for performing this, including IRAF, RegiStax, Autostakkert, Keiths Image Stacker, Hugin, and Iris.

In the lucky imaging approach, only the best short exposures are selected for averaging. Early shift-and-add techniques aligned images according to the image centroid, giving a lower overall Strehl ratio.

Speckle interferometry
In 1970, the French astronomer Antoine Labeyrie showed that Fourier analysis (speckle interferometry) can obtain information about the high-resolution structure of the object from the statistical properties of the speckle patterns. This technique was first implemented in 1971 at Palomar Observatory (200-inch telescope) by Daniel Y. Gezari, Antoine Labeyrie and Robert V. Stachnick. Methods developed in the 1980s allowed simple images to be reconstructed from this power spectrum information.

One more recent type of speckle interferometry called  speckle masking' involves calculation of the bispectrum or closure phases from each of the short exposures. The "average bispectrum" can then be calculated and then inverted to obtain an image. This works particularly well using aperture masks. In this arrangement the telescope aperture is blocked except for a few holes which allow light through, creating a small optical interferometer with better resolving power than the telescope would otherwise have. This aperture masking technique was pioneered by the Cavendish Astrophysics Group.

One limitation of the technique is that it requires extensive computer processing of the image, which was hard to come by when the technique was first developed. This limitation has faded away over the years as computing power has increased, and nowadays desktop computers have more than enough power to make such processing a trivial task.

Biology
Speckle imaging in biology refers to the underlabeling of periodic cellular components (such as filaments and fibers) so that instead of appearing as a continuous and uniform structure, it appears as a discrete set of speckles. This is due to statistical distribution of the labeled component within unlabeled components. The technique, also known as dynamic speckle enables real-time monitoring of dynamical systems and video image analysis to understand biological processes.

Example images
All of these were obtained using infrared AO or IR interferometry (not speckle imaging) and have higher resolution than can be obtained with e.g. the Hubble Space Telescope. Speckle imaging can produce images with four times better resolution than these.
 * WR 104
 * WR 98a
 * LKHa 101
 * MWC 349A
 * Betelgeuse

title: Speckle imaging


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User:Sunbeam60

I am from Denmark, but currently live in England.

title: User:Sunbeam60


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User talk:Sunbeam60

I am not entirely certain Sunbeam60 is a human... I require further proof. Mmmmk. How could I prove that to you? This is, after all, the medium in which a Turing test is most likely to fail? In fact, is this sentence written by a computer? You'll never know.

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title: User talk:Sunbeam60