Instrumentation at BBSO

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Instrumentation at BBSO
Big Bear Solar Observatory New Jersey Institute
of Technology
12 Apr 2007
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Instrument Development?InfraRed Imaging
Magnetograph( IRIM )
Instrumentation Development I -- IRIM
12 Apr 2007
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What is IRIM ?

• Wavelength Range 1 1.6 ?m ( Fe I
  1.5648 ?m and Fe I 1.5652 ?m )
• Large Field of View 180"180"
• Four Operation Modes
• a) Polarimetry Stokes I, Q, U, V gt B
• b) Spectrometry spectral line profile gt T,
  p
• c) Dopplergram a few selected spectral
  points gt V
• d) Photometry narrow (0.1Å),
  medium(2.5Å), broad(50Å) gt dynamics
• High Spatial Resolution close to diffraction
  limit
• High Temporal Resolution lt 1 min
• Moderate Spectral Resolution ?/d? 105
• High Throughput gt 35 for polarized light
• High Magnetic Sensitivity V / I 10-4

a
c
d
b
IRIM is an infrared imaging tunable
spectro-polarimeter
12 Apr 2007
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How does IRIM work ?
IRIM Fabry-Perot Etalon Birefringent Lyot
Filter Interference Filter
IRIM FPI Lyot IF
12 Apr 2007
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IRIM optical layout for 65 cm Telescope
Telecentric F / 120
IRIM optical layout
12 Apr 2007
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Element I Fabry-Perot etalon

• Fabry-Perot Interferometer (FPI)

• Narrow Band Filter
• Tunable Filter

• Etalon Model ET70FS-1041
• Working Wavelength 1 1.6 ?m
• Clear Aperture 70 mm
• Nominal Finesse 60 _at_ 1523 nm
• Controller Model CS100-8105
• Cavity Spacing 2226 ?m
• Cavity Scan Range gt 4.1 ?m
• Plate Flatness gt ? / 100 _at_ 546.1 nm

12 Apr 2007
FPI is a narrow-band tunable filter
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Calibration I Fabry-Perot etalon

• FSR, FWHM, and Finesse

FSR
FSR 5.505 ? 0.104 Å FWHM 8.8 pm 0.088 Å
FWHM
12 Apr 2007
FSR, FWHM, Finess of FPI
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Calibration I Fabry-Perot etalon

• FPI Control Scan Step 0.00292 Å / Step

• Plate Flatness Roughness

Flatness ? / 306 _at_ 1523 nm Roughness ? /
1842 _at_ 1523 nm

• Peak Transmission

• Stability and Repeatability

12 Apr 2007
Control step, flatness, roughness
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Element II Birefringent Lyot Filter

• Lyot Birefringent Filter System

• Working Wavelength Fe I 1.5648 1.5652 ?m
• Clear Aperture 36 mm
• Passband FWHM 2.5 Å
• Tunable Range 100 Å
• Peak Transmission 38 for polarized
  light 18 for
  non-polarized light
• Internal Structure 4-module
• Thermal Controller 32.0 0.1C

Design Requirement
12 Apr 2007
Lyot filter is the order sorting filter of FPI
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Instrument II Lyot filter

• Optical Design

• Wide field configuration 1 incident angle
• LCVR tuning 100 Å tunable wavelength range
• Oil-free structure compact, easy maintenance

Unique techniques in the design
12 Apr 2007
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Calibration II Lyot filter

• Calibration

John W. Evans Solar Facility National Solar
Observatory/Sacramento Peak Jun. 2004 and Nov.
2004
Lyot filter calibration
12 Apr 2007
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Calibration II Lyot filter

• Calibration

Calibration supply voltages at any wavelength
desired
12 Apr 2007
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Calibration II Lyot filter

• Result Fe I 1.5648 ?m 1.5652 ?m

Transmission and symmetrical profile
12 Apr 2007
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Calibration III Interference filter
IF isolates side-lobe peaks of Lyot filter
12 Apr 2007
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Element IV Camera

• Rockwell Infrared Camera

• Material HgCdTe ( MCT)
• Wavelength 1 2.5 ?m
• Operation Temp 80 K with LN2
• Format 1024 ? 1024
• Pitch 18 ?m
• Frame Rate 30 Hz
• Well Capacity 400,000 carriers
• Window CaFl
• Camera Output 14 bit LVDS
• Data Acquisition PCI Based Matrox Meteor
  Camera Link II
• Camera Sync Frame, Line, Pixel, Trigger
• Readout Ripple
• Price 150,000

TCM8600 Performance Specifications
Infrared Rockwell Camera
12 Apr 2007
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Calibration IV Camera

• Linearity nonlinearity lt 1
• _at_ 2000 9000 ADU
• Gain and Readout Noise
• g 22.5 e- / ADU
• Readout Noise ? 110.9 e- Dynamic Range
  71.96 dB
• Vacuum and Cooling Ability
• Hot Defect Pixels lt 0.5

System characteristic evaluations
12 Apr 2007
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Instrument Development ?Adaptive Optics System
Instrumentation Development II -- AO
12 APR 2007
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How ?
Phase Conjugation
Principle of Adaptive Optics (AO)
12 Apr 2007
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Wavefront Sensor
Correlating Shack Hartmann WFS
AOs Eye Wavefront Sensor
12 Apr 2007
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Control Computer and DSP
Baja AO76 CAMERA 200x200 10 ports 66
MHz 2500 fps
40 DSPs
SMART INTERFACE Camera To DSPs Sorts Pixels Into
Subapertures
ch0
ADSP-21160 SHARC DSP
ch1
Link Port To RS422
ch2
Deformable Mirror
ch3
ch4
ch5
Tip/Tilt Mirror
ch6
ch7
D/A
Monitor
ch8
ch9
Keyboard
Motor Controller
Host Computer/AO Control System
WFS field Stop motor
AOs Brain DSP
12 Apr 2007
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Deformable Mirror

• manufacturer Xinetics Inc.
• actuator number 97
• clear aperture 77.47 mm
• grid spacing 7 mm
• mechanical stroke 4.8 µm
• actuator capacitance 1.66 µF
• operating voltage 100V (7030V)
• frequency response 4 kHz
• hysteresis lt 1
• influence function 10 _at_ nearest
• coating gt 95
• optical quality ptv 0.128?
• rms
  0.025?

27 Feb 2007
AOs Hand Deformable Mirror
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Current AO-76 for 65 cm Telescope
AO and Conjugation planes
27 Feb 2007
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Scientific Results
High-resolution observation with AO
12 Apr 2007
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Observation( AO IRIM )
Observation
12 Apr 2007
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Observation I Polarimetry

• Diffraction limited polarimetry on Jul. 1, 2005
• 
  IR Filters Lyot Filter
  Fabry-Peort Etalon
• 
  Polarization Analyzer IR
  Camera AO

NIR 1.5648 ?m Bandpass 0.1 Å FOV
145" x 145", Frame rate 5/s, exposure
time 100 ms Image scale 0.143" Scan
step 58 mÅ Scan from -1.45 Å to 1.45 Å
Intergration 40 frames Telecentric Setup
F-ratio 120
Observation I IRIM Polarimetry
12 Apr 2007
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Observation I Polarimetry

• Observation and Data NOAA 10781 on Jul.
  1, 2005

Longitudinal magnetogram
12 Apr 2007
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Observation I Polarimetry

• Observation and Data NOAA 10781 on Jul.
  1, 2005

Stokes Inversion
Spectral sequence of magnetograms
12 Apr 2007
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Observation I Polarimetry

• IRIM and MDI

IRIM Polarimetry show higher magnetic sensitivity
12 Apr 2007
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Observation II Photometry

• IR High-Resolution Observation of X10 WL Flare
  on Oct. 29, 2003

IR Pre-Filter IR Camera AO
NIR 1.567 ?m ? 2.5 Å 91.2" x 91.2", Frame
rate 30/s, save 50 frames/min
Visible 0.52 ? 0.025 ?m 81" x 81, Frame
rate 15/s, took 200 f/min and save 100
Observation II IRIM Photometry
12 Apr 2007
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Observation II Photometry

• NIR Observation NOAA 10486

Left Panel Speckle reconstructed image of active
region NOAA 10486 obtained with frame selection
and high-order AO system at
1648UT on 2003 October 29. The annotation of
the axes refers to
heliographic coordinates corresponding to a FOV
of 81" x 81" Right Panel NIR image of the
same active region during the flare taken on
2042UT with a FOV of
91" x 91 ". The bright patches marked by white
boxes are NIR flare kernels.
The first flare observed in the near infrared
12 Apr 2007
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Observation II Photometry

• Photospheric Shear Flows

Photospheric flows and magnetic field
configuration fo NOAA AR 10486 on 2003 November
29. To illustrate the high spatial resolution LCT
results, we provide different views of (a)
flow vectors, (b) azimuth angle of the
velocity vectors, (c) magnitude of
the velocity vectors (d) MDI magnetogram
with superposed magnetic neutral
lines.
Strong shear flows along magnetic neutral line
12 Apr 2007
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope Project
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
With 1.6 meters of useful aperture, the NST will
be the largest solar telescope in the
world. Coupled with an adaptive optics system,
the telescope will provide unprecedented
resolving power for studies of the solar surface,
chromosphere and low corona. Unique probe of the
origin of space weather. Why locate this
powerful system at BBSO?
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Big Bear Solar Observatory New Solar Telescope
Big Bear Solar Observatory BBSO has been in
operation since 1969. The dome sits at the end
of a 1000 ft. causeway on Big Bear Lakes north
shore at 6,750 foot elevation. The observatory
benefits from the usually sunny California
weather and its unique position in the San
Bernardino mountains.
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Big Bear Solar Observatory New Solar Telescope
Big Bear Solar Observatory The surrounding waters
of Big Bear Lake reduce ground level convection,
and predominate winds bring smooth air flows
across the flat surface of the lake providing
superb conditions for solar observing. Studies of
the seeing characteristics at BBSO show that the
best seeing occurs when winds are from the west.
This wind direction dominates more than 90 of
the time.
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Big Bear Solar Observatory New Solar Telescope
Big Bear Solar Observatory The character of the
seeing at Big Bear differs markedly from the high
altitude, volcanic island sites measured in the
ATST site survey. The median rO for BBSO is shown
in black. Best known site in the world for
sustained solar observations. Observations using
adaptive optics will be viable for extended
periods during a typical day. The NST primary
mirror will be an additional 6 meters above lake
level compared to the detector system used to
take these data.
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Big Bear Solar Observatory New Solar Telescope
AO corrected image from the 65cm
telescope. Image 1 Frame selection Image 2
Speckle Reconstruction Image courtesy of
Carsten Denker and Alexandra Tritschler.
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Optical Configuration The NST is an off-axis
section of a 5.3 meter, F/0.73 parabolic parent
with an elliptical secondary. The off-axis
distance is 1.84 m resulting in a 1.6 meter,
F/2.4 primary. Optical Parameters F/52
system EFL 8.32 m Plate Scale 2.48 arc
sec/mm 180 arc sec field Gregorian image 72.6
mm
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Optical Configuration The NST configuration is a
1/5 scale copy of one segment of the Giant
Magellan Telescope. The NST primary is being
figured by Steward Obs. Mirror Lab as a
technology test for the GMT, greatly reducing
mirror figuring costs for the NST project. The
NST secondary mirror was manufactured by Space
Optics Research Labs.
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Mechanical Structure The Optical Support
Structure (OSS) is being designed and
manufactured by DFM Engineering. Installation is
scheduled for the fall of 2007. The off-axis
optics drive the OSS to an unusual
configuration. Inside-out Fork Unconventional
Tube Assembly Tilted Primary Mirror
Cell Unbalanced OTA Moving Counter-weights
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Automated Mirror Supports The secondary mirror
is mounted to an agile hexapod allowing automated
adjustment of telescope alignment while
observing. The primary mirror is supported by 36
active supports that can be remotely adjusted to
correct figure errors caused by temperature
changes and telescope motions.
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Dome A new dome has been constructed to house
the NST. The insulated fiber-reinforced plastic
shell is supported by a steel frame. A small
entrance aperture limits the sunlight that can
enter the dome and heat the interior. Automated
vent gates will be controlled to allow natural
wind flushing of the dome and telescope. A forced
ventilation system will also be active to exhaust
air from the dome.
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Dome All systems on the current dome floor will
be removed. A new pier will be built to support
the NST. A low thermal mass work deck will be
added to allow access to the telescope.
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Cooling Systems The primary mirror will absorb
heat during observations. An off-the-shelf
liquid to air heat exchanger will be used to
force air across the front and back of the
primary mirror. The systems can be tailored by
adjusting coolant temperature, airflow speed and
ducting. Air will be filtered to reduce dust
around the primary.
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Heat Stop The primary mirror will deliver about
2000 Watts to the prime focus. The heat stop
will reflect most of this radiation and allow
about 23 Watts through the prime focus field
stop. The reflective surface of the heat stop
will be cooled using jets of chilled fluid
impinging on its back wall. The system is being
developed by the University of Hawaii.
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Instrumentation Two instrument stations will be
used with the NST A nasmyth platform is
available on the telescope, primarily for
infrared observations. This station will be used
for initial optical testing of the NST since the
optical path is much less complex. The nasmyth
will incorporate an active tip/tilt mirror and
correlation tracker to provide stabilized images.
The images will be diffraction-limited at
infrared wavelengths.
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Big Bear Solar Observatory New Solar Telescope
The New Solar Telescope
Instrumentation Two instrument stations will be
used with the NST The coude lab provides
stable optical benches in a temperature
controlled environment. A spectrograph and 2
magnetographs are planned for the initial
observing campaigns. The coude will be fed by
the adaptive optics module allowing
diffraction-limited imaging at all wavelengths.
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Big Bear Solar Observatory New Solar Telescope