Transit of Venus Observations
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Transit of Venus Observations From National Solar Observatory. National Solar Observatory Facilities. Dunn Solar Telescope Sunspot, New Mexico, USA D = 76cm, λ =380-1700 nm. McMath-Pierce Telescope Kitt Peak, Arizona, USA D = 160 cm, λ =1000-5000 nm. Transit Conditions – Sacramento Peak.

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Transit of Venus Observations From National Solar Observatory

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Transit of Venus Observations

From National Solar Observatory


National Solar Observatory Facilities

Dunn Solar Telescope

Sunspot, New Mexico, USA

D = 76cm, λ=380-1700 nm

McMath-Pierce Telescope

Kitt Peak, Arizona, USA

D = 160 cm, λ=1000-5000 nm


Transit Conditions – Sacramento Peak


Interferometric BIdimensional Spectrometer (IBIS)

Dual Fabry-Perot Imaging Spectrometer

P.I. - Fabio Cavallini (INAF/Arcetri)

Facility Instrument at the NSO/Dunn Solar Telescope since 2005

Publication List: http://tinyurl.com/ibis-pubs

Instrument Design: Cavallini, F., 2006, Solar Phys., 236, 415.

Spectral Profile: Reardon, K., Cavallini, F., 2008, A & A, 481, 897.

MTF: Righini, A., Cavallini, F., Reardon, K., 2010, A & A, 515, 85.

References


Interferometric BIdimensional Spectrometer (IBIS)

  • Spectral Range: 5400 - 8600 Å

  • FWHM:20-45 mÅ

  • FOV:98 x 98 arcsec

  • Pixel Size: 0.098 arcsec2/pixel

  • Exposure Times:20-50 msec

  • Strehl Ratio: ~0.95

  • Frame Rate: 8 – 12 frames/sec

  • Data Rate:≥ 100 GB/hour (two CCD’s)

  • Application of post-facto image correction techniques:

    • Destretching

    • Speckle Reconstruction

    • Multi-Object Multi-Frame Blind Deconvolution

Spectral resolution ~200,000 – 260,000

  • Available Filters

  • 543.4 – Fe I [g=0]

  • 617.3 – Fe I (SDO/HMI)

  • 630.1/630.2 – Fe I

  • 676.8 – Ni I (MDI ; GONG)

  • 709.0 – Fe I [g=0]

  • 722.4 – Fe II [g=0]

  • 587.6 – He I D3

  • 589.0 – Na D2

  • 589.6 – Na D1

  • 656.3 – Ha

  • 854.2 – Ca II


  • Mercury Transit – 06 November 2006

    Hα Imaging at Ingress

    IBIS/DST


    Mercury Transit – 06 November 2006 – IBIS/DST

    Imaging Spectroscopy of planetary transit

    Na D2 589.0 nm : Scan range = 1.5 Å : Δλ = 0.009 Å

    0.083 arcsec/pixel


    Mercury Transit – 06 November 2006

    IBIS/DST Observations of Mercury Exosphere in Na D2

    Equivalent

    Width

    Gaussian

    Amplitude

    Gaussian

    Shift

    Gaussian

    Width


    IBIS Field of View

    Mercury

    d=10”

    98 x 98 arcsec


    IBIS Field of View

    Venus

    D=60”

    98 x 98 arcsec


    Spectral Line Selection for IBIS

    • Upper wavelength limit of 8700 Å

    • Need strongest line to improve SNR

    • Need to minimize contamination from other solar or terrestrial spectral lines

    • Pascal Hedelt simulated Venus CO2 absorption spectrum from 780 – 4500 nm

    • Compared simulated spectrum (corrected from vacuum to air wavelengths!) to solar atlas


    Spectra at 870 nm – Noisy Continuum!

    Solar + terrestrial atlas spectrum

    Simulated Cytherian CO2 spectrum


    Solar, Terrestrial, Cytherian Spectra – 780 nm

    Solar + terrestrial atlas spectrum

    Simulated Cytherian CO2 spectrum


    Solar, Terrestrial, Cytherian Spectra

    IBIS Prefilter Profile

    Solar + terrestrial atlas spectrum

    Simulated Cytherian CO2 spectrum


    Imaging of Aureole

    Rapid Oscillations of the Solar Atmosphere (ROSA)

    http://star.pst.qub.ac.uk/rosa/

    Six Andor 1000 x 1000 pixel CCD’s,

    30 frames/sec sustained

    + image reconstruction techniques

    Will use ROSA to take multiwavelength observations (380 – 500 nm) at high cadence during ingress

    Look for wavelength dependence of aureole due to scattering processes

    Possible addition of 2k x 2k, 50 fps detector

    For higher cadence and resolution


    Facility Infrared Imaging Spectrograph(FIRS)

    Full Stokes Spectropolarimetry

    Slit scanning

    Slit length

    Spectral coverage: ~60 Å (λ/250)

    Observe same spectral interval as Hedelt et al. 2011?


    McMath-Pierce TelescopeNSO Array Camera (NAC)

    Full Stokes Spectropolarimetry

    1024x 1024, helium cooled, InSb array

    Spectral Range: 1.6 –2.5 μm, 4.67 μm

    Spectral Resolution: ~50,000 – 70,000

    Spectral coverage: ~60 Å

    Spectral interval(s) to observe?

    1.6 and/or 2.2 μm bands


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