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Mission Overview

Outer Planet Atmospheres Legacy (OPAL)


Primary Investigator: Amy Simon

HLSP Authors: Amy Simon

Released: 2015-10-13

Updated: 2024-05-14

Primary Reference(s): Simon et al. 2015

DOI: 10.17909/T9G593

Citations: See ADS Statistics

Read Me

Source Data:

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.


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"

Data Products

The data files have the following naming convention:



  • <planet> = one of "jupiter", "saturn", "uranus", or "neptune"
  • <rotation> = the rotation+epoch of the observation, in the format of <year><letter>, e.g., "2015a" is the first rotation of Jupiter from Cycle 22, and "2015b" is the second rotation from Cycle 22. Keep in mind that HST cycles span two calendar years since they start in Oct. and run through Sep. of the following year.
  • <type> = Data product type, either "globalmap" for the science data product and full-size preview images, or "globalmap-medium" and "globalmap-small" for the smaller-sized preview images.
  • <ext> = File extension, either "fits" for the science data products, "tif" for the preview images, or "png" for the web-friendly version of the preview images.

Data file types:

_globalmap.fits Mosaic (projection) for the given filter.
_globalmap.tif Preview image (size varies by target).
_globalmap-medium.tif Preview image (width x height ~ 900 x 450 px, varies by target).
_globalmap-small.tif Preview image (width x height ~ 450 x 225 px, varies by target).
_globalmap-small.png Web-friendly version of the small-sized preview image.

Data Access

Jupiter Saturn Uranus Neptune
Jupiter Cycle 22 (Jan. 2015) N/A Uranus Cycle 22 (Nov. 2014) Neptune Cycle 22 (Sep. 2015)
Jupiter Cycle 23 (Feb. 2016) N/A Uranus Cycle 23 (Sep. 2015) Neptune Cycle 23 (Oct. 2016)
Jupiter Cycle 24 (Apr. 2017) N/A Uranus Cycle 24 (Sep. 2016) Neptune Cycle 24 (Oct. 2017)
Jupiter Cycle 25 (Apr. 2018) Saturn Cycle 25 (Jun. 2018) Uranus Cycle 25 (Oct. 2017) Neptune Cycle 25 (Sep. 2018)
Jupiter Cycle 26 (Jun. 2019) Saturn Cycle 26 (Jun. 2019) Uranus Cycle 26 (Nov. 2018) Neptune Cycle 26 (Sep. 2019)
Jupiter Cycle 27 (Aug. 2020) Saturn Cycle 27 (Jul. 2020) Uranus Cycle 27 (Nov. 2019) Neptune Cycle 27 (Aug. 2020)
Jupiter Cycle 28 (Sep. 2021) Saturn Cycle 28 (Sep. 2021) Uranus Cycle 28 (Oct. 2020) Neptune Cycle 28 (Sep. 2021)
Jupiter Cycle 29 (Nov. 2022) Saturn Cycle 29 (Sep. 2022) Uranus Cycle 29 (Dec. 2021) Neptune Cycle 29 (Sep. 2022)
Jupiter Cycle 30 (Jan. 2024) Saturn Cycle 30 (Oct. 2023) Uranus Cycle 30 (Nov. 2022) Neptune Cycle 30 (Sep. 2023)
    Uranus Cycle 31 (Sep. 2023)  



Please remember to cite the appropriate paper(s) below and the DOI if you use these data in a published work. 

Note: These HLSP data products are licensed for use under CC BY 4.0.