DRE
Project 15.2 - HIG] SPEED PHOTOGRAPHY
EARLY FIREBALL GROWTH
Project 15,2 operated Station 1520 on Runit for the
information on the growth of the very early fireball,
'
ot to obtain
One of the purposes for
such a study was to gain knowledge about reproducibility of
‘
eel
py
eet
Se,
bombs. The exact geanetry of bonb and case will be fired again in the I
°
shot, and the degree of difference of the two early fireball expansions should
give data on the relative yields of the two bonbs, Unfortunately ae
will probably be changed to a lower yield for enolot contrary”
earlier expectations.
Thus the information to be obtained by comparison of thd
ae er.
ace
ae~
to
oO
shots will be a scaling law and not reproducibility data.
Even tW’ecaling law will not be too good because the yield of the
or
that shot will not be known very well,
Cameras were operated in Station 1520 also to study the fireball growth in
color and in frame pictures.
The experimentel setup was identical to that de-
scribed in the Project 15.2 Pre-operational Report.
Station 1590, the wooden mirror shed in front of station 1520, was rebuilt
EgShot to allow viewing of the 300 foot tower,
The arrangement
of the turning mirrors in the photobunker and the perspective introduced by the
orientation of the tower made the tower appear tilted in the pictures,
The
slits within the streak cameras were set at an angle of about 114 degrees from
the horizontal to line up on the horizontal direction of the cab,
Mirror dis-
tortion corrections were made in the focus position to give very good dynamic
focus,
For full speed, 4,000 rps, the slit is moved forward 3/4 inch,
The half
&peed correction is £ inch, and the quarter speed correction is 1/8 inch,
M
Lay £0
~ 4 -
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