Try changing
z inside
powN2 
z = abs(zr*vec3( cos(zo)*cos(zi), cos(zo)*sin(zi), sin(zo) ))
or just add z=abs(z) after z = zr*vec3( cos(zo)*cos(zi), cos(zo)*sin(zi), sin(zo) )
#preset julia1
FOV = 0.62536
Eye = 1.91991,-1.7193,-4.14192
Target = -1.0681,0.455671,3.91224
Up = -0.503567,-0.862689,0.0461452
AntiAlias = 1
Detail = -2.78761
DetailAO = -1.57143
FudgeFactor = 1
MaxRaySteps = 164
BoundingSphere = 49.057
Dither = 0.42105
NormalBackStep = 5.1667
AO = 0,0,0,0.90123
Specular = 4.4304
SpecularExp = 16
SpotLight = 0.435294,0.737255,1,1
SpotLightDir = 0.65626,0.5
CamLight = 1,0.941176,0.898039,0.8077
CamLightMin = 1
Glow = 1,1,1,0.46575
GlowMax = 20
Fog = 0
HardShadow = 0.35385
ShadowSoft = 12.9032
Reflection = 0
BaseColor = 1,1,1
OrbitStrength = 0
X = 0.5,0.6,0.6,0.7
Y = 1,0.6,0,0.4
Z = 0.8,0.78,1,0.5
R = 0.4,0.7,1,0.12
BackgroundColor = 0.6,0.6,0.45
GradientBackground = 0.3
CycleColors = false
Cycles = 1.1
EnableFloor = false
FloorNormal = 0,0,0
FloorHeight = 0
FloorColor = 1,1,1
Iterations = 19
ColorIterations = 2
Power = 1.42224
Bailout = 21.1365
AlternateVersion = true
RotVector = 0.27848,0,0.06329
RotAngle = 92.5722
Julia = true
JuliaC = -1.53192,-1.02128,0.29788
#endpreset
#preset julia2
FOV = 0.62536
Eye = 3.64263,-4.96651,-2.54797
Target = -1.39772,1.28526,1.19882
Up = -0.721929,-0.674489,0.154259
AntiAlias = 1
Detail = -2.78761
DetailAO = -1.57143
FudgeFactor = 1
MaxRaySteps = 164
BoundingSphere = 49.057
Dither = 0.42105
NormalBackStep = 5.1667
AO = 0,0,0,0.90123
Specular = 4.4304
SpecularExp = 16
SpotLight = 0.435294,0.737255,1,1
SpotLightDir = 0.65626,0.5
CamLight = 1,0.941176,0.898039,0.8077
CamLightMin = 1
Glow = 1,1,1,0.46575
GlowMax = 20
Fog = 0
HardShadow = 0.35385
ShadowSoft = 12.9032
Reflection = 0
BaseColor = 1,1,1
OrbitStrength = 0.14286
X = 0.411765,0.6,0.560784,0.41748
Y = 0.666667,0.666667,0.498039,-0.16504
Z = 1,0.258824,0.207843,1
R = 0.0823529,0.278431,1,0.82352
BackgroundColor = 0.607843,0.866667,0.560784
GradientBackground = 0.3261
CycleColors = true
Cycles = 4.04901
EnableFloor = false
FloorNormal = 0,0,0
FloorHeight = 0
FloorColor = 1,1,1
Iterations = 19
ColorIterations = 2
Power = 1.24448
Bailout = 21.1365
AlternateVersion = true
RotVector = 0,0.32911,0.34177
RotAngle = 180
Julia = true
param = 16
JuliaC = -7.06822,0.09096,-1.23404
#endpreset
absbulb

I just realized that I hijacked this thread! Sorry everyone!