The Wide Field Coverage for Juno (WFCJ) program is synchronized with perijove passes of the NASA Juno mission. "Perijove" is the close-approach atmospheric overflight of Juno during its highly eccentric 53-day orbit. The Juno spacecraft orbit is very eccentric, allowing microwave and infrared scans of the atmosphere from a vantage point inside the planet's intense radiation belts. Although Juno is equipped with a visible wavelength public-outreach camera (JunoCam), the proximity to Jupiter during the perijove passes means that Juno itself cannot obtain regional-scale or global-scale imaging data to provide context for its own observations. The WFCJ program fills this gap with WFC3/UVIS imaging data. Some perijoves will be covered by a single orbit of HST imaging ("snapshot" coverage), while other perijoves will be covered by pairs of global maps ("global" coverage). Observing for two rotations allows the measurement of the speed of Jupiter's wind jets, which vary with latitude: the zonal wind profile (ZWP).
Juno's first perijove passes happened when Jupiter was too close to the Sun to be observed by Hubble. Perijove 3 (PJ3) was the first observable science pass, featuring global coverage.
The data are organized by sub-directory based on the perijove number they belong to. Each file name follows the formula described below. Each epoch is differentiated by a calendar year and a perijove designation, e.g., "jupiter-2016pj03" is for perijove 3 during 2016.
- <obs> is the observatory, "hst" or "gemini"
- <ins> is the science instrument, either "wfc3-uvis" (WFC3/UVIS) or "niri" (NIRI)
- <yyyy> is the year
- <num> is a two- or three-character value, containing the two-digit, zero-padded Perijove Number. An optional sequence letter (e.g., "b") may be added to indicate data from epochs that were observed in between perijoves, such as OPAL program observations or NRAO time exchange observations.
- <filter> is the filter(s) used
- <time> gives detailed timing info for individual frames, or approximate midpoint times for Gemini mosaics, written as <ddmm>ut<hhmm>. For WFC3 cylindrical map mosaics or polar mosaics, <time> is "rot1", "rot2", etc. for separate Jupiter rotations. The separate rotations may or may not be consecutive.
- <ext> is the type of data product
Complete example file names are:
Data file types:
†Footprints are for the MWR instrument (Janssen et al. 2017 <https://doi.org/10.1007/s11214-017-0349-5>). If necessary, footprints have been advected by the zonal wind field to compensate for east/west drift of atmospheric features during the time interval between Juno and HST/Gemini observations.
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Note: Polar files can be found in the Global and Snapshot webpages.
|Perijove Number||First Obs. Date (UT, YYYY-MM-DD)||Map/Image Data (click links to load tables)||Zonal Winds (click links to download files)|
|ASCII | FITS|
|3||2016-12-11||WFC3 Global | NIRI 5-μm||ASCII | FITS|
|3b||2017-01-11||WFC3 Global | NIRI 5-μm||ASCII | FITS|
|4||2017-02-02||WFC3 Global | NIRI 5-μm||ASCII | FITS|
|5||2017-03-27||WFC3 Snapshot||ASCII | FITS|
|6||2017-05-19||WFC3 Snapshot | NIRI 5-μm|
|7||2017-07-11||WFC3 Snapshot | NIRI 5-μm|
|12||2018-04-01||WFC3 Global | NIRI 5-μm||ASCII | FITS|
|12b||2018-04-17||WFC3 Global||ASCII | FITS|
|13||2018-05-24||WFC3 Snapshot | NIRI 5-μm|
|14||2018-07-16||WFC3 Snapshot | NIRI 5-μm|
|19||2019-04-06||WFC3 Global | NIRI 5-μm||ASCII | FITS|
|20b||2019-06-26||WFC3 Global | NIRI 5-μm||ASCII | FITS|