AEOS Telescope +Image-Slicer/ Spectrograph

Data Reduction and Results for June 8, 2006

• 3.7-meter telescope with adaptive optics

• Scale: 0.5 arc-seconds per fiber

• 1-minute exposures

• Twilight not significant

• Calibrated with standard stars

• June 8: 10 data cubes

• June 9: 8 data cubes

AEOS + Image-Slicer Spectrograph:Observing parameters

Mercury

Flat Field

SodiumLamp

AEOS + Image-Slicer Spectrograph: Raw Data

Mercury

Flat Field

AEOS + Image-Slicer Spectrograph:Remove Spectral Curvature

AEOS + Image-Slicer Spectrograph:

Locate Each Fiber at Each Wavelength

• Choose wavelength (row)

• Fiber brightness = sum of 5 pixels

• Don’t spatially align the spectral images– Would increase fiber-to-fiber contamination– Fiber spacing varies over the image

AEOS + Image-Slicer Spectrograph:Image Reconstruction Method

AEOSReconstructed Images

Mercury reconstructed

Flat field reconstructed

Final Image (continuum)

Each raw image yields a data cube of 1024 images

• Ganymede spectrum =

solar spectrum without Na emission

• (Ganymede spectrum) x (Merc. Image) =

artificial data cube of Mercury w/o Na

• Subtract artificial data cube from real data cube to yield Na emission

AEOS + Image-Slicer Spectrograph:Subtraction of surface-reflected solar spec.

-

=

Mercury at D1+D2 Merc. x Gany. at D1+D2

Na Exosphere

Surface (Continuum) Sodium Exosphere (D1+D2)

Absolute brightness uncertainty: ~20%

June 8, 2006|---- 3’’ ----|