Frankfurt - 09 December 2004

A CORONAGRAPH FOR THE QUAFF MISSION: Q-COR

Philippe Lamy

Laboratoire d’Astrophysique de Marseille

Frankfurt - 09 December 2004

CORONAGRAPH HERITAGE

•LASCO-C2•LASCO-C3•STEREO-KCOR

LASCO C2

Field of View: 1.5-6.0 R

Sensitivity: 2·1072·1010 B

Frankfurt - 09 December 2004

Frankfurt - 09 December 2004

LASCO C3Field of view: 3.7-30 R

Sensitivity: 3·1091011 B

Optical parameters of COR2 (STEREO mission)

Frankfurt - 09 December 2004

COR2 optical layout

Frankfurt - 09 December 2004

Frankfurt - 09 December 2004

Optical parameters of Q-COR

Field of View 2-15 Rsun solar elongation (±3.5°)

Spatial Scale 15 arcsec/13 m-pixel

Focal Plane Array 2048 × 2048, 13 m-pixel, 14 bit/pixel

Bandpass 450-600 nm

Exposure times 3 s; 3 exposures required for pB

Synoptic Cadence 1 min.

Maximum Cadence 10 s

Effective Focal Length 185 mm

Stray-light (B) to Disk light (Bo) < 10e-11 B/Bsun

A CORONAGRAPH FOR QUAFF: Q-COR

Subsystem Select Comment

Optical concept KCOR Except O1 (C2) and FOV FOV vs spatial resolution

Optical contact – AR Coated

Structure TBD Rectangular (C2) or tube (KCOR)

Door KCOR-C2 ~ similar design

Ext occulter + AØ C2 Simpler – Superior performances

Light tube C2-KCOR Simple ray tracing

HRM KCOR or C2

O1 C2 Doublet in optical contact-AR Coated

IOCS C2 Not available on KCOR

O2 KCOR

Shutter KCOR Placed in front of O3 (pupil)

Lyot Spot C2

O3 KCOR

Polarizer wheel KCOR Placed in front of CCD

CCD camera ?

Pointing Error Syst C2 If required

S/C Mounting-Pointing ?

Boresighter ?

Frankfurt - 09 December 2004

SPARE PARTS AVAILABLE FROM LASCO-C2• Optical components mounted in their barrels

- lenses- filters + color correctors- polarizers- HRM (heat rejection mirror)

• External occulter + AO• Pointing error system PES• Internal occulter centering system IOCS*• Focusing mecanisms*• Internal calibration system (tungsten lamps)• Shutter*• Filter and polarizer wheels*

CAVEATS- No motors(*)- No rad-hard optical components- No structure- Single set

Frankfurt - 09 December 2004

SOME OUTSTANDING ISSUES

• S/C mounting

• Pointing Strategy

• FOV Clearance

• Radiation damage

• Internal calibration

• Focusing mechanism (air/vacuum)

• Focusing on OE

Frankfurt - 09 December 2004

Q-COR work packages