Your target was the first atomic bomb test in New Mexico, 1945 and to describe the blast.The following websites will provide you with pictures and more information:
http://www.eyewitnesstohistory.com/atomictest.htm
http://www.pbs.org/wgbh/aso/databank/entries/dp45at.html
http://nuclearweaponarchive.org/Usa/Tests/Trinity.html
