Scientists who have exhumed the remains of Danish astronomer Tycho Brahe say tests aimed at solving the mystery of his sudden death will take until next year.

An international team opened his tomb this week in the Church of Our Lady Before Tyn near Prague's Old Town Square, where Brahe has been buried since his death in 1601, and took samples of his remains.

Jens Vellev, a professor of medieval archaeology at Aarhus University, Denmark, said the scientists will not only be able to reconstruct what Brahe looked like but got enough material to trace details about his life years before his death.

He said an eight-centimeter (3.15 inches) long piece of mustache should make it possible for them to see "what kind of medicine he took in the last three months of his life" while from samples of bones they can go as far as back as 15 years before his death.

Brahe made extraordinarily accurate stellar and planetary observations that helped lay the foundations of early modern astronomy, but the circumstances surrounding his death at age 54 are murky.

Brahe was long believed to have died of a bladder infection but recent tests have indicated mercury poisoning could be the cause.

CT scans done this week at Prague's Na Homolce are expected to result in 3D models of the bones that will be used to recreate Brahe's entire skeleton. An X-ray technique known as PIXE analysis and a neutron activation analysis will be conducted on the samples at the Nuclear Research Institute in Rez, near Prague, and further testing will take place in Denmark and Sweden before final results are released in 2011.

Besides the remains of Brahe and his wife, who was buried by his side in a wooden coffin, archaeologist Petr Veleminsky said researchers discovered the remains of five children and three other adults in the tomb.

"That was a surprise for us," Veleminsky said.

Brahe's remains were being reburied later Friday during a ceremony led by Prague archbishop Dominik Duka.