Think Tank

Welcome

The JunoCam webpages are designed to open the door to the public to participate in the steps a spacecraft instrument team follows in implementing their experiment: Planning, Discussion, Voting (decision-making) and Processing. We are pleased to add “Think Tank” as the next step in this sequence. Eventually we will add the final endpoint: “Results”.

This section will be a bit more wonky. You are invited to see the science sausage-making in action. There will be links to engineering files that we call kernels. There will be discussion threads on science topics we think can be addressed by particular images. You will see maps that connect features in JunoCam images to the historical record and context.

If you would like to be involved in this group please contact us.

Tools of the trade

Reports

Various citizen scientists have contributed to the field using JunoCam data. Below are some of the reports and other resources to get more information

Links:
British Astronomical Association https://britastro.org/
British Astronomical Association - Jupiter Section https://britastro.org/section_front/15
Unmanned Spaceflight http://www.unmannedspaceflight.com/

JunoCam Maps Archive

In this section are collections of global maps made from JunoCam’s color images at each perijove. Juno is in a highly elliptical, near-polar orbit, so on each orbit JunoCam takes well-resolved images within just a few hours around closest approach, which is called perijove (PJ). As Juno is moving very rapidly at that time, the camera scans a 58-degree-wide field of view in narrow red, green and blue strips, and a single image is assembled from a long sequence of these strips taken during one rotation of the spacecraft at 2 rpm. The movement between successive strips makes it essential to reproject them to produce a single image; then, to compensate for distortions caused by movement and perspective, and to combine multiple images and put them in context, it is essential to reproject the images into maps. The intention of the JunoCam project was for this to be done by citizen scientists, so that is the origin of the maps in this archive.

Three sets of maps are provided here in three projections: cylindrical (global), south polar, and north polar. Each set is a provided as a ZIP file covering 8 or more perijoves, with maximum file size 48 MB.

The maps were all made by Gerald Eichstädt and John Rogers, with a few exceptions as noted individually. For most perijoves, the maps have also been posted in the individual perijove reports by J.R. (available on this site under ‘Reports’ and ‘Predict Maps’), often with annotations. Here, all maps are given without annotations, although annotated copies of some are included. Scales of latitude (planetocentric) and longitude (System 3, L3) have been added to most maps. There is some variation in format, especially for the early perijoves.

The raw images were processed and map-projected by G.E., then the single-image maps were composited by J.R., except for the later perijoves when G.E. used a semi-automatic assembly technique. There are small uncertainties in navigation so positions may be uncertain by a few pixels. Intensities and color balance are arbitrary, and have been adjusted to reduce visible seams between images and to enhance regional contrast. Therefore, any broad diffuse features should not be relied on without consulting the original single-image maps. Adjustment of color balance was especially necessary in the later years as the raw images became progressively redder due to effects of radiation on the camera. For JunoCam’s methane-band images, G.E. also made map projections, which have been assembled and included here for some but not all perijoves.

The cylindrical (global) maps are in equirectangular projection at 10 pixels/degree and with L3=0 at the centre. The polar maps are in polar azimuthal equidistant projections at various scales, with L3=0 to the left for the south, L3=0 to the right for the north. In addition to the regular south polar maps, we include compilations of such maps from JunoCam and from ground-based observers which are Supplementary Figures for a published paper. In addition to the regional north polar maps, from PJ41 onwards we include higher-resolution sets of latitudes above 70 or 75°N, showing the circumpolar cyclones.

For further details of the separate map sets, please see the ‘ReadMe’ files posted with each group.

Most of the maps are in JPEG format, to keep file sizes manageable, but TIF or PNG files are available from J.R. if needed.

The global coverage has varied during six years of the mission due to the evolution of Juno’s orbit and the constraints of spacecraft orientation. JunoCam mainly views the northern hemisphere when inbound and the southern hemisphere when outbound. In the first year, JunoCam usually covered both hemispheres extensively. In subsequent years, coverage was often less complete, but with resolution higher over parts of the northern hemisphere, lower over the southern hemisphere. There were no images at PJ2 and PJ71, none of the northern hemisphere at PJ19 and PJ48, and none of the southern hemisphere at PJ56.

The maps are provided under a CC-BY license: “The CC BY license allows anyone to: copy, distribute and transmit work; adapt work; make commercial use of the work under the condition that the user must attribute the work in the manner specified by the author or licensor (but not in any way that suggests they endorse the user or their use of the work).” I.e. these maps are in the public domain but should always be credited as indicated (NASA / JPL / SwRI / MSSS / Gerald Eichstädt / John Rogers); and we ask that anyone wishing to use them for research or commercial purposes would contact us.

These sets of maps, and all individual perijove reports, can also be found on the BAA Jupiter Section web site at: https://britastro.org/sections/jupiter (under ‘JunoCam Global Maps’ and ‘Results from Juno: Jupiter's polar regions’).

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CYLINDRICAL MAPS: ReadMe

(1) CYLINDRICAL MAPS (PJ1-PJ48)

These are composite RGB maps in equirectangular projection using planetocentric latitudes, usually at 10 pixels/degree and with L3=0 at the centre. Latitude and longitude (L3) scales have been added to most maps. Formats were variable at the early perijoves.

The raw images were processed and map-projected by Gerald Eichstädt, then the single-image maps were composited by John Rogers, except for some of the later perijoves when G.E. experimented with an automatic assembly technique. There are two exceptions (PJ22 & PJ29) when we present maps by Brian Swift instead, having been posted on the JunoCam web site.

At the first few perijoves the close-up images were not included in the maps, and the longitude orientation was approximate (± 1-2°), as we deduced it by alignment with ground-based observations before accurate navigation was established.

(2) CYLINDRICAL MAPS (PJ49-PJ72)

Most of the cylindrical maps in this batch were assembled by G.E. using a semi-automated procedure, sometimes followed by adjustments by J.R. to reduce artefactual disparities in brightness and color. Hence, the color balance is still arbitrary. G.E. also produced methane-band (CH4) maps for all images, only some of which have been assembled and included here.

After PJ50, Juno’s minimum altitude was always on the dark side of Jupiter, so the maps are composites of inbound and outbound imagery. Up to PJ60, inbound images covered most of the planet -- sometimes over two successive rotations, so some regions could be mapped twice and ‘blinked’ to show the currents, though only the last inbound rotation gave high resolution. The inbound trajectory did not give good views of the high southern latitudes, which were supplied from a subsequent outbound rotation. (G.E.’s separate maps for each rotation are available if needed.) From PJ62 onwards, inbound coverage was reduced to only one sector of the northern hemisphere, and outbound coverage was still restricted to >~18°S.

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First batch:
JunoCam-global-maps_PJ1-PJ12
JunoCam-global-maps_PJ13-PJ24
JunoCam-global-maps_PJ25-PJ36
JunoCam-global-maps_PJ37-PJ48

Second batch:
JunoCam-global-maps_PJ49-PJ60
JunoCam-global-maps_PJ61-PJ72
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SOUTH POLAR MAPS: ReadMe

(1) SOUTH POLAR MAPS, 2016-2020 (PJ1-PJ26)
The following four ZIP files contain polar projection maps of Jupiter’s south polar region from JunoCam (2016-2020, PJ1-PJ26) and from amateur ground-based observers (2018 & 2020). These maps were used in analysing the structure and dynamics of the south polar region, as reported in Rogers et al. (2022)*; the third and fourth sets are Supplementary Figures for that paper.

The JunoCam maps are in polar azimuthal equidistant projection with planetocentric latitude scale. Maps at early perijoves were not produced as systematically as at later ones.

One set of JunoCam maps is in colour (RGB), with the edges set at 60°S; the second set is in the 889-nm methane band (CH4), with the edges set at the equator. The first CH4 map herein is for PJ9. The third set consists of four TIF files which are pairs of RGB maps that can be blinked to show the wind patterns.

The fourth set contains ground-based maps, which are in polar orthographic projection with planetographic (2018) or planetocentric (2020) latitude scale, produced using WinJUPOS The images were created by the observers as named and the maps by Andy Casely, Rob Bullen and John Rogers. They are stacked TIF’s of multiple maps, either in RGB or in near-infrared.

* J.H. Rogers, G. Eichstädt, C.J. Hansen, G.S. Orton, T. Momary, A. Casely, G. Adamoli, M. Jacquesson, R. Bullen, D. Peach, T. Olivetti, S. Brueshaber, M. Ravine, S. Bolton. ‘Flow patterns of Jupiter’s south polar region.’ Icarus 372, paper 114742 (2022 Jan.; online, 2021 Nov.). https://doi.org/10.1016/j.icarus.2021.114742

S-polar-maps_JunoCam-RGB_PJ1-PJ26.zip
S-polar-maps_JunoCam-CH4_PJ1-PJ24.zip
SPR-maps_JunoCam_Suppl-Figs-S1b-S4b.zip
SPR_ground-based-map-sets_2018&2020.zip

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(2) SOUTH POLAR MAPS, 2020-2025 (PJ27-PJ72)

The following three ZIP files contain polar-projection colour maps of Jupiter’s south polar region from JunoCam (2020-2025, PJ27-PJ72). They were all made on Juno’s outbound trajectory. Because of Juno’s orbital evolution, the outbound image resolution has continuously declined.

Up to PJ33, the maps were made down to 60°S at the edges; from PJ34 onwards, down to 30°S, though often cropped to 45°S in these versions. The scale for these is usually 30 pixels per degree latitude. Some filenames include an indication of the map scale (e.g. ‘20px’ means 20 px/deg) and the latitude range (‘45S’ means down to 45°S at the edges).

From PJ46 onwards, some maps are in PNG format, mostly presented unlabelled, covering latitudes down to 45°S at the edges. For these maps, G.E. used a semi-automated assembly method, eliminating the need for manual compilation. The map scale was usually reduced to reflect the decreasing image resolution.

PJ27-PJ33_Set-of-S-Polar-maps
PJ34-PJ46_Set-of-S-polar-maps
PJ47-PJ72_Set-of-S-Polar-maps

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NORTH POLAR MAPS: ReadMe

(1) NORTH POLAR REGIONAL MAPS (PJ1-PJ40)

These polar projection maps of Jupiter’s north polar region from JunoCam are all in polar azimuthal equidistant projection, with planetocentric latitude scales, at 10 pixels per degree latitude. All have L3=0 to the right. There is some variation in format, especially for the early perijoves. They cover as much as possible of the region >60°N, plus some lower-latitude areas. Most of them extend down to the equator or to 30°N at the edges. In many cases a circle of 20°N latitude is included, or a larger extent of coordinates.
At the first few perijoves the longitude orientation was approximate (± 1-2°), as we deduced it from the apparent subsolar longitude before accurate navigation was established. The maps are in TIF format in the ZIP files below.

Maps from PJ01-PJ10: JunoCam-NPR-maps_PJ01-10
Maps from PJ11-PJ20: JunoCam-NPR-maps_PJ11-20
Maps from PJ21-PJ30: JunoCam-NPR-maps_PJ21-30
Maps from PJ31-PJ40: JunoCam-NPR-maps_PJ31-40

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(2) NORTH POLAR REGIONAL MAPS (PJ41-PJ72)

There are still some variations in the scale and extent of the maps in the early perijoves in this set, but from PJ49 onwards, they are routinely presented down to 45°N at the edges, at 30 px/deg. Before PJ49, maps were generally compiled as described for the previous batch. From PJ49 onwards, G.E. used a semi-automated assembly method, eliminating the need for manual compilation.

PJ41-PJ50_N-polar-maps
PJ51-PJ72_N-polar-maps

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(3) NORTH POLAR CYCLONES MAPS (PJ41-PJ72)

In addition to the north polar region maps posted above, we provide full-resolution maps of the latitudes >70 or 75°N, to show the circumpolar cyclones (CPCs). As Juno’s perijove drifted northwards, the resolution on the northern CPCs has increased; these maps are provided at 60 px/deg or, more recently, 120 px/deg.

Strong enhancement has been applied to bring out maximum detail in the terminator region. Some of the maps have also been sharpened by blending with a small proportion of a “high-pass” version produced by G.E. (filtered for high spatial frequencies). In addition to the unlabelled maps, our individual perijove reports often included copies with the CPCs labelled, and combined maps from pairs of perijoves to show the complete pattern of the CPCs; a few of these are also included in these ZIP files. There were no images of the CPCs at PJ48, PJ61, or PJ71.

The changes in the northern CPCs during the mission have been described in our perijove reports, and in EPSC presentations:Rogers JH, Eichstaedt G, Hansen CJ, Orton GS & Momary T (2021) ‘Behaviour of Jupiter’s polar polygons over 4 years’. EPSC Abstracts Vol. 15, EPSC2021-57. https://doi.org/10.5194/epsc2021-57.

Brueshaber S, Williams I, Rogers JH, Eichstaedt G. Orton G, Hansen C, Fletcher LN & Bolton S (2025), ‘Morphological and Positional Changes in Jupiter’s Northern Polar Cyclones’. EPSC Abstracts Vol. 19, EPSC-DPS2025-711.

PJ41-PJ60_N-polar-CPCs-maps_75N
PJ62-PJ72_N-polar-CPCs-maps_75N

APO-22 Maneuver

By MissionJuno.com on 2020-06-05 UT

Command audio from Juno's apoapsis maneuver to jump Jupiter's shadow.

Latest comment 2 years ago