Truman never issued the order to drop either bomb, and was reported to be "surprised" at the short amount of time between the dropping of the bomb on Hiroshima and the dropping on Nagasaki. After Nagasaki, he issued an order that no further bombs were to be dropped without his express authorisation. As we know, no further bombs were dropped.
Nagasaki was the secondary target that day, having only very recently been added to the list of targets. The orders stipulated that visual contact had to be made before the bomb could be dropped, because the alternative method of bomb aiming (radar) was deemed too inaccurate (0.5 - 1.0 miles off target). When the plane got to Nagasaki, there was no visual confirmation possible until the last moment when the bomb aimer claimed he saw a small break in the cloud cover, enough to drop the bomb through. The bomb exploded 0.75 miles off target.
Nagasaki was the secondary target that day, having only very recently been added to the list of targets. The orders stipulated that visual contact had to be made before the bomb could be dropped, because the alternative method of bomb aiming (radar) was deemed too inaccurate (0.5 - 1.0 miles off target). When the plane got to Nagasaki, there was no visual confirmation possible until the last moment when the bomb aimer claimed he saw a small break in the cloud cover, enough to drop the bomb through. The bomb exploded 0.75 miles off target.
