Jupiter Absolute Reflectivity Calibration Home Page


I. Introduction

Welcome to the Jupiter Absolute Reflectivity Calibration Home Page. This page was designed to provide observers with a means to calibrate Jupiter observations from the Comet Shoemaker-Levy 9 epoch to an absolute brightness scale. The contents of this page are based on a publication by N. Chanover et al., "Absolute Reflectivity Spectra of Jupiter: 0.25 - 3.5 Microns" (Icarus 121,351-360). Click here for the final version (PostScript) of the paper.

The figures for the paper are in separate PostScript files. Click on the individual figure names to view them:

Figure 1a, Figure 1b, Figure 2, Figure 3, Figure 4. Figure 5.

II. Data

Much of the information presented in the above publication can be seen here on this page in graphical and/or tabular form. It will also be available in the AAS CD ROM series, Volume 7. All graphics are in PostScript form unless otherwise noted. These data sets include:

  • Filter transmission curves

    The transmission curves (% Transmission vs. Wavelength) are plotted for all the visible wavelength filters used in this study, both for HST and ground-based data.

    Here are the links to the TABULATED filter transmission curves in the visible wavelengths:

    Hubble Space Telescope (Instrument: WFPC2)

    255 nm, 336 nm, 410 nm, 547 nm, 893 nm, 953 nm. [Note: Filter transmission values are between 0 and 1; multiply by 100 to get percent transmission.]

    Tortugas Mountain Observatory (Instrument: CCD)

    450 nm, 560 nm, 727 nm, 755 nm, 800 nm, 829 nm, 889 nm, 968 nm. [Note: Columns in these files are sample number, wavelength (nm), and percent transmission of filter (%).]

    For the near-infrared filters, there are several sets of transmission curves:

    Apache Point Observatory (Instrument: GRIM)

    1.58 microns: This is an image of the actual filter scan (from the filter manufacturer).
    1.70 microns: This is an image of the actual filter scan (from the filter manufacturer).
    1.99 microns: No scan was available from the builders of GRIM, so this is a synthetic curve made using the specs described in Table II of the paper and a truncated Gaussian.
    2.122 microns: This is an image of the actual filter scan (from the GRIM engineers).
    2.22 microns: This is an image of the actual filter scan (from the GRIM engineers).
    2.36 microns: This is an image of the actual filter scan (from the GRIM engineers).

    TABULAR forms are available for the following filters: 1.99 microns. The columns in this file are wavelength (microns) and percent transmission of filter (%). Remember, this is a synthetic filter transmission curve. The rest of the filter transmission curves come directly from the filter manufacturer and are not available in tabular form.

    Palomar Observatory (Instrument: NIR camera)

    Transmission curves for CVF wavelengths used at Palomar. No actual transmission curve exists for this circular variable filter (CVF), so a synthetic one was created using a triangle function with its top fifth truncated (as suggested by the instrument engineer, Keith Matthews of CalTech).

    A master table exists for the following wavelengths: 2.00, 2.10, 2.20, 2.35, 3.40, and 3.50 microns. The wavlengths in microns are listed with the percent tranmission (again, remember that these are synthetic transmission curves).

    Infrared Telescope Facility (Instrument: NSFCAM)

    Transmission curves for CVF wavelengths used with NSFCAM. No actual transmission curve exists for this CVF, so a synthetic one was created using a triangle function with idealized transmission (100%).

    A master table exists for the following wavelengths: 1.75, 2.00, 2.04, 2.07, 2.10, 2.14, 2.27, 3.30, and 3.41 microns. The wavlengths in microns are listed with the percent tranmission (again, remember that these are synthetic transmission curves).

  • Jupiter albedo spectra

    The full-disk albedo is plotted and tabulated for both the visible and near- infrared wavelength regions. For the visible wavelengths, the data are published (Karkoschka, E. 1994. Spectrophotometry of the Jovian planets and Titan at 300- to 1000-nm wavelength: the methane spectrum. Icarus 111, 174), and were communicated personally by the author. Here are the graphical and tabular forms.

    For the near-infrared wavelengths, the data are published (Clark, R. N. and T. B. McCord 1979. Jupiter and Saturn: Near-infrared spectral albedos. Icarus 40, 180), and were obtained through the Planetary Data System (PDS). Here are the graphical and tabular forms.

  • Absolute reflectivity spectra

    Click here for tabulated values of Absolute Reflectivity (I/F) vs. Planetographic Latitude in the visible wavelengths. I/F is tabulated for every degree of planetographic latitude visible on the planet, for all the visible wavelengths described in the paper (Table I) and in the visible filter transmission curve section above. PostScript version , ASCII version.

    Click here for tabulated values of Absolute Reflectivity (I/F) vs. Planetographic Latitude in the near-IR wavelengths. I/F is tabulated for every degree of planetographic latitude visible on the planet, for all the near-IR wavelengths described in the paper (Table II) and in the near-IR filter transmission curve section above. Note: the column titles in the data files indicate the central wavelength and the observatory from which the data set was taken (A = Apache Point Observatory, P = Palomar Observatory, and I = Infrared Telescope Facility). The Palomar data does not extend further north than about +40 degrees in most cases. This is because the field-of-view was such that the entire planet could not be imaged at once, and observations were made to optimize the view of the southern hemisphere since that's where the SL9 fragments impacted. PostScript version (1.70 - 2.10 microns) , PostScript version (2.12 - 3.41 microns) , ASCII version (1.70 - 2.10 microns) , ASCII version (2.12 - 3.41 microns).


    III. Sample Images

    There are also some sample images available so you can see the kinds of data that were used to construct this calibration tool.

    NOTES:

    1) In some cases these may not be the exact images used for this analysis.

    2) The images are all greyscale. If your monitor is unable to display all levels of grey while simultaneously running your Web browser (e.g. Netscape or Mosaic), save the images (which are in GIF form) to your own machine and display them with your favorite image software.

    Click on the data set you would like to see sample images of:

  • Visible Wavelength Images

    Hubble Space Telescope

    NMSU Tortugas Mountain Observatory

  • Near-Infrared Wavelength Images

    Apache Point Observatory

    Palomar Observatory

    Infrared Telescope Facility


    IV. Comments/Questions

    If you have any comments or questions about this page or the materials presented herein, click here to send an email message to Nancy Chanover directly.



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