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Outer Planet Atmospheres Legacy (OPAL)

Simon et al., 2015, ApJ, 812, 55

See also:
Wong et al., 2015, LPI, 46, 2606 Simon et al., 2016, ApJ, 817, 162 Stauffer et al., 2016, AJ, 152, 142
Irwin et al., 2017 Icarus, 288, 99 Tollefson et al., 2017 Icarus, 296, 163 Simon et al., 2018 AJ, 155, 4
Johnson et al., 2018 Planetary and Space Sci., 155, 2-11 Wong et al., 2018 AJ, 155, 117 Fletcher et al., 2018 AJ, 156, 67
Simon et al., 2018 AJ, 156, 79S Toledo et al., 2018 GeoRL, 45, 5329-5335 Bjoraker et al., 2018 AJ, 156, 3
Hsu et al., 2019 AJ, 157, 152 Simon et al., 2019 GeoRL Sánchez-Lavega et al., 2019 Nature Astronomy
Cosentino et al., 2019 Journal of Geophysical Research: Planets, 124, 5 Hueso et al., 2020 Icarus, 336, 113429 Wong et al., 2020 ApJS, 247, 58


Description of Data Products

Data Access


Projections of two rotations from a Cycle for Jupiter, Uranus, Neptune, and Saturn. Watch how cloud features change between rotations.

OPAL is a project to obtain long time baseline observations of the outer planets in order to understand their atmospheric dynamics and evolution as gas giants. The yearly observations from OPAL throughout the remainder of Hubble's operation will provide a legacy of time-domain images for use by planetary scientists. The project will ultimately observe all of the giant planets in the solar system (Jupiter, Saturn, Uranus, and Neptune) in a wide range of filters. The images are processed using an ellipsoid limb-fitting technique, with an additional fringe correction applied to the narrow-band filters only (e.g., FQ889N for Jupiter 2014-2015), which amounts to a few percent correction. Mosaics are created for each observed filter in a projection that spans 360 degrees of longitude. See the README files (on disk or in the tables below) for additional details on the data processing. The mosaics from each filter (in FITS format), as well as previews (in TIF format) are provided.

How To Acknowledge

Any publication that uses images or maps from the OPAL program should include the following statement in the Acknowledgments:

"This work used data acquired from the NASA/ESA HST Space Telescope, associated with OPAL program (PI: Simon, GO13937), and archived by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. All maps are available at"

Description of Data Products

Each file name begins with the same prefix: "hlsp_opal_hst_wfc3-uvis_". The name of the planet is the next part of the filename. Each rotation/epoch is differentiated by a calendar year and a letter, e.g., "jupiter-2015a" is the first rotation of Jupiter from Cycle 22, "jupiter-2015b" is the second rotation from Cycle 22, etc. Keep in mind that HST cycles span two calendar years, since they start in Oct. and run through Sep. of the following year. The next part of the filename includes the HST filter for that mosaic/preview image, followed by a version number and the file extension. File extensions are:

  1. _globalmap.fits = Mosaic (projection) for the given filter.
  2. _globalmap-medium.tif = Preview image (width x height ~ 900 x 450 px, varies by target).
  3. _globalmap-small.tif = Preview image (width x height ~ 450 x 225 px, varies by target).
  4. _globalmap.tif = Preview image (size varies by target).

Data Access

You can retrieve the images and previews from the table below, or directly at this URL.

Cycle (Year)JupiterSaturnUranusNeptune
22 (Oct 2014 - Sep 2015) Load Table   Load Table Load Table
23 (Oct 2015 - Sep 2016) Load Table   Load Table Load Table
24 (Oct 2016 - Sep 2017) Load Table   Load Table Load Table
25 (Oct 2017 - Sep 2018) Load Table Load Table Load Table Load Table
26 (Oct 2018 - Sep 2019) Load Table Load Table Load Table Load Table
27 (Oct 2019 - Sep 2020) Load Table Load Table Load Table Load Table
28 (Oct 2020 - Sep 2021)     Load Table