Vacuum System Vibration Analysis on the Keck Telescopes Michael Cooney W.M. Keck Observatory.
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Transcript of Vacuum System Vibration Analysis on the Keck Telescopes Michael Cooney W.M. Keck Observatory.
Vacuum System Vibration Vacuum System Vibration Analysis on the Keck Analysis on the Keck
Telescopes Telescopes
Michael CooneyMichael Cooney
W.M. Keck ObservatoryW.M. Keck Observatory
BackgroundBackground
Secondary MirrorSecondary Mirror
Vacuum SystemVacuum System
Why Reduce Why Reduce VibrationsVibrations
Creating Test PlansCreating Test Plans
The JobThe Job
Test SetupTest Setup
Data CollectionData Collection
Data ReductionData Reduction
Data AnalysisData Analysis
Test ConditionsTest Conditions
Keck 1 and 2Keck 1 and 2
Taking DataTaking Data
Two RegulatorsTwo Regulators
Keck 1 Secondary Mirror Keck 1 Secondary Mirror AccelerationAcceleration
Average Acceleration
1
10
100
1000
10000
100000
1000000
10000000
0.0 100.0 200.0 300.0 400.0 500.0
Frequency
ug
^2/
Hz
Avg Accelerationof new regulator
Avg Accelerationof old regulator
Average acceleration is less, especially at higher Average acceleration is less, especially at higher frequencyfrequency
80 Degree ElevationPink: Old System Blue: New System
Keck 1 Displacements Keck 1 Displacements
Displacement larger with the new regulator at 15Hz and Displacement larger with the new regulator at 15Hz and 19Hz19Hz
80 Degree ElevationDark colors: Old System Light colors: New System
Displacement: K1 2005194 00:30:00 10,000 pts only
1
10
100
1000
10000
100000
0 10 20 30 40 50 60 70 80 90 100
freq
nm
^2/
Hz
(ph
ysic
al)
ch10-s1
ch11-s2
ch12-s3
ch13-dsm
pri piston
sec piston
sec tilt x
sec tilt y
tert tilt x
tert tilt y
total piston
sec+tert tilt x
sec+tert tilt y
incoh pri piston
ch10-s1-OLD
ch11-s2-OLD
ch12-s3-OLD
sec piston-OLD
sec tilt x -OLD
sec tilt y -OLD
Keck 1 Mirror MovementKeck 1 Mirror Movement
Mirror is pistoning at low frequenciesMirror is pistoning at low frequencies Mirror is tilting in y at low frequenciesMirror is tilting in y at low frequencies
Displacement: K1 2005194 00:30:00 10,000 pts only
0.0
50.0
100.0
150.0
200.0
250.0
0 10 20 30 40 50 60
freq
sec piston
sec piston-OLD
Displacement: K1 2005194 00:30:00 10,000 pts only
0.0
50.0
100.0
150.0
200.0
250.0
300.0
0 10 20 30 40 50 60
freq
sec tilt x
sec tilt y
sec tilt x -OLD
sec tilt y -OLD
Piston Effect: Pink is New; Blue is Old
Tip-Tilt Effect: Pink is New; Blue is Old
Keck 2 Secondary Mirror Keck 2 Secondary Mirror AccelerationAcceleration
Average acceleration is lessAverage acceleration is less Acceleration around 20 Hz is largerAcceleration around 20 Hz is larger
Dark Colors: Old System Light Colors: New System
Acceleration: K2 2005178 22:30:00 10,000 pts only
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
0 100 200 300 400 500
freq
ug
^2/
Hz
ch10-s1
ch11-s2
ch12-s3
ch13-dsm
pri piston
sec piston
sec tilt x
sec tilt y
tert tilt x
tert tilt y
total piston
incoh pri piston
ch10-s1-OLD
ch11-s2-OLD
ch12-s3-OLD
sec piston-OLD
sec tilt x -OLD
sec tilt y -OLD
Results Keck 2Results Keck 2
Above 30Hz frequency shows less displacementAbove 30Hz frequency shows less displacement Concerned with displacements between 10Hz and 30HzConcerned with displacements between 10Hz and 30Hz
80 Degree ElevationYellow: Old System Pink: New System
Average Displacements: K2 2005178 22:30:00 10,000 pts only
1
10
100
1000
10000
100000
0.0 10.0 20.0 30.0 40.0 50.0 60.0
Frequency
nm
^2
/Hz
(ph
ys
ica
l)
New Regulator
Old Regulator
Keck 2 Mirror MovementKeck 2 Mirror Movement
Mirror is pistoning at low frequenciesMirror is pistoning at low frequencies Mirror is tilting in y at low frequenciesMirror is tilting in y at low frequencies
Piston Effect: Pink is New; Blue is Old
Tip-Tilt Effect: Pink is New; Blue is Old
Displacement: K2 2005178 22:30:00 10,000 pts only
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
0 10 20 30 40 50 60
freq
sec piston
sec piston-OLD
Displacement: K2 2005178 22:30:00 10,000 pts only
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
0 10 20 30 40 50 60
freq
sec tilt x
sec tilt y
sec tilt x -OLD
sec tilt y -OLD
Conclusions Keck 1Conclusions Keck 1
Keck 1:Keck 1: Unexpected pistoning, tip-tilt, and Unexpected pistoning, tip-tilt, and
displacements are largerdisplacements are larger Acceleration is lessAcceleration is less Amplified natural resonance of telescopeAmplified natural resonance of telescope
Stiffer structure?Stiffer structure? Coupling issue to contend withCoupling issue to contend with
More tests to verify dataMore tests to verify data
Conclusions Keck 2Conclusions Keck 2
Keck 2:Keck 2: Displacements on a whole are Displacements on a whole are
acceptableacceptable Pistoning and tip-tilt are mostly same or Pistoning and tip-tilt are mostly same or
lowerlower Acceleration mostly lowerAcceleration mostly lower Feed forward system to take out Feed forward system to take out
displacementdisplacement
AcknowledgementsAcknowledgements
Jason ChinJason Chin Dwight ChanDwight Chan Ed Wetherell Ed Wetherell Sarah Anderson Sarah Anderson Malika Bell Malika Bell W.M. Keck Observatory W.M. Keck Observatory Center for Adaptive OpticsCenter for Adaptive Optics University of Hawaii-Manoa University of Hawaii-Manoa Funding provided through the Center for Adaptive Optics, a Funding provided through the Center for Adaptive Optics, a National Science Foundation Science and Technology Center National Science Foundation Science and Technology Center (STC), AST-987683 (STC), AST-987683
