SOLAR-C
High speed spectro-polarimeter
Use SP like FG!	
２００８ February 3	
Saku Tsuneta (NAOJ)	

Scientific requirement	• Multiple dynamical phenomena wasdiscovered with Hinode:	
– Spectrographic observations become moreimportant	– Cadence to cover TBD area as fast as 10 sec
is needed.	
– We need to maintain <0.2 arcsec spatial
resolution to see small scale features such as
THMF.	

Implication to hardware	• Want to maintain basic SOT/OTA
architecture due to development burden• Spectrograph type instrument rather thanfilter-based instrument is still needed for
precise Stokes polarimetry• Classical slit scan does not work. Multi-slit
spectrograph would help, but we needmulti-object spectropgrah with many
simultaneous pixels. 	

Multi-object spectrograph	• Night-time astronomy	
– NASA James-Webb space telescope micro-shutter
array (NASA GSFC)	

• Fibre-based multi-object spectrograph– Being developed by Spanish IAC for VTT	VTT specrograph	
Focal plane

OpticsSecond focus	
Two orthogonal images

Grating

Detector

Modulator
Analyzer

Optics

OpticsCollimator optics

Camera lens

Second focal plane of VTT（IAC Manolo Collados）	
Micro-pupil	

Micro field-lens on
VTT second focalplane	Fibre unit	

SecondMicro-lens	

Lens focus	

Micro-lensarray unit	

Second micro-lens	aray	

Pupil 	
（infinite＝on grating）	

Location of fibre optics（IAC Manolo Collados）	
Focal planeOptics

Two orthogonal images

Modulator
Analyzer

Optics

Grating

Detector

Fibre optics	

OpticsCollimator optics

Camera lensApplication to SOT/FPP	
YYＸ	

X1
λX1

Micro-lens array on
FPP focal plane	Xm

Ｘ１	 Ｘ２	 Ｘ３	

Fibremapping	Ｘｎ	

４kx４k FPP CMOS

Ｘｍ	Optical layout of SOT
Litrow Mirror

Spectoro-polarimeter

Polarizing BS

Dual 256 x 1024 CCD

X3 Mag lensPolarizing BS
Folding Mirrors

Folding Mirror

Shutter
Slit

Field lensGrating
Filterwheel

Field lens

X2 Mag lensShutterPreslit

Broadband Filter Instrument

Filterwheel

Field Mask

2048 x 4096 CCD

Narrowband Filter Instrument
50 x 50 CCD

SecondaryTelecentric
Correlation Trackerlenses
Demag lensBeam Distributor
Reimaging Lens

Folding Mirror

Folding Mirror

Image Offset Prisms
Folding Mirror

Primary

Polarization
Modulator
CLUTip Tilt Mirror

OTAColor CodingOTA
Common Optics
CT
NFI
BFI
SP

Where is it located？	
Litrow Mirror

Spectoro-polarimeter

Polarizing BS

Dual 256 x 1024 CCD

X3 Mag lensPolarizing BS

here	

Folding Mirror

Shutter
Slit

Field lensGrating
Filterwheel

Field lens

X2 Mag lensShutterPreslit

Broadband Filter Instrument

Filterwheel

Field Mask

2048 x 4096 CCD

Narrowband Filter Instrument
50 x 50 CCD

SecondaryTelecentric
Correlation Tracker
lensesDemag lensBeam Distributor
Reimaging Lens

Folding Mirror

Folding Mirror

Image Offset Prisms
Folding Mirror

Primary

PolarizationModulator
CLUTip Tilt Mirror

OTA
Color Coding
OTA
Common Optics
CTNFI
BFISP

FPP with multi-object
spectrograph	• Fibre optics on the FPP SP slit	
• Fibre does not preserve the polarization state	
– Move polarization beam splitter in front of SP CCD tobefore-fibre optics	
• 4k x 4k CMOS instead of CCD	• Simultaneous observations of ２５６ wavepoints and１６ｘ４
０９６ pixel = 40arcsec sqrd FOV. We need scan mirror
for wider FOV• Multiple line obs with blocking filter	• Use SP like FG