The photograph is expected to raise at least £5,000 because of the rich and controversial history of the couple, who occupied the "Millionaires' Cabin" on the 882-ft Belfast-built ship, which was capable of carrying 3,547 passengers and crew.  The couple's marriage in September 1911 had created controversy in New York, coming soon after Mr Astor divorced his wife, Ava, the mother of his two sons.  His elder son, Vincent, was just a year younger than Madeleine when the wedding took place. At the time, divorce was rare and remarriage was even rarer.  After the wedding, the newlyweds decided to go on a six-month honeymoon to Europe and north Africa to escape the gossipmongers.  They sailed across the Atlantic from New York to Southampton on the Titanic's sister ship, Olympic.  On their return journey, the couple had cabins 62 and 64 on the Titanic after boarding the ship at Cherbourg.  They are believed to have paid $4,350 each for their one-way tickets – more than £45,000 at today's prices.  After the Titanic struck the iceberg just before midnight on April 14, Mr Astor left their cabin suites to investigate and returned to reassure his wife that the accident did not appear serious.  For a time, the couple even sat chatting in the ship's gymnasium.  Even as the lifeboats were being filled with some of the 2,223 passengers and crew on board, Mr Astor initially ridiculed the idea of leaving the safety of the ship's solid decks for the small craft.  "We are safer here than in that little boat," he said.  By 1.45am, however, the ship was sinking and Mr Astor, a businessman and property developer, helped his wife, who was five months pregnant, into a lifeboat under the "women and children first" protocol.  While some men bribed their way on to lifeboats and others hid under women's dresses, Mr Astor refused to buy or force his way on to a lifeboat.  His body was eventually recover on April 22 and given the identification number of "124".  His personal effects included a gold watch, gold and diamond cuff links, a diamond ring, £225 in notes, $2,240 in notes, and various gold and silver pieces and coins. He was eventually buried at Trinity cemetery, New York.  Mrs Astor gave birth to her son on August 14, 1912, and called him John Jacob Astor V in memory of her husband and the boy's father.  She later remarried and relinquished all claims to the Astor millions – worth billions of pounds today.  However, her second marriage and, later, a third marriage failed and she eventually died in Palm Beach, Florida, in 1940, aged 47 - coincidentally, the same age that her first husband had died at 28 years earlier.  The photograph will be auctioned in Devizes, Wiltshire, next Saturday by Henry Aldridge & Son, the world's leading auctioneers for Titanic memorabilia.  The auction catalogue describes the six-by-four-inch black-and-white photograph as "a poignant and stunning portrait" and says Mrs Astor is sporting a "subtle Mona Lisa smile".  Demand for Titanic memorabilia has increased over the past decade. Museums and private individuals are among the 10,000-plus collectors looking to buy the ship's artefacts.  Andrew Aldridge, a third-generation auctioneer with is family firm, said: "For most people, the story of the Titanic is about the people who were on board.  "However, others are interested in its engineering and literally the nuts and bolts of the ship."  Other items for sale next week include a letter, written by Adolphe Saalfeld, a perfumer, on Titanic headed notepaper and dated April 10.  In it, he wrote: "I am the first man to write a letter on board. They [staff] are still busy to finish the last things on board."  The letter is expected to fetch more than £20,000 – by claiming it was the first letter to be written on the ship Mr Saalfeld, unwittingly, doubled its value.  Memorabilia belonging to Barbara Dainton West, who was a ten-month-old baby on board the ship when it went down yet died last year aged 96, is expected to fetch more than £60,000. In 1912, she was the second-youngest of the 702 survivors.
A poignant photograph of Madeleine Astor, a pregnant woman who survived the   sinking of the Titanic, is to go on sale.