[9] Jupiter in 2014/15: Animated maps from ground based images.

Jupiter in 2014/15: Report no.9
Animated maps of Jupiter from ground-based astro-imagers

Recently, NASA posted a pair of maps of Jupiter produced from Hubble Space Telescope images on 2015 Jan.19, taken 10 hours (one rotation) apart, which vividly showed the planet’s currents at high resolution:


Here, by way of comparison, we present a series of five global maps from ground-based amateur observers, covering 2015 Feb.27 –Mar.1 and March 4-7, plus two maps of the equatorial region. ‘Blinking’ between them dramatically shows the planet’s jets (most obviously near the equator, but also up to high latitudes), and shearing of disturbed regions within the major belts, and relative motions of innumerable small spots.

The maps are from images by Kevin Quin (USA), Damian Peach (Barbados), Tiziano Olivetti (Thailand), and Christopher Go (Philippines), plus one image by Bruce Macdonald (USA).  Quin made his own maps; the others were made by Marco Vedovato. All maps were made using WinJUPOS.  During this period, observers worldwide were trying to image the planet intensively, but bad weather affecting European observers prevented the completion of hi-res maps covering any single rotation of the planet.  The maps have been arranged so that they follow in sequence within each longitude sector, with intervals of one to four rotations between them (even though this sometimes required splitting different sectors from a single rotation between successive maps).  The 5 global maps are in System II longitude with south up.  Major spots are labelled on the first two of them. The maps are presented here in an animated GIF but the original (larger) maps can be provided if required.

Also, we present two composite maps of the equatorial region, from the same image sequences, in System I longitude with south up.  In three sectors, the maps are one rotation apart, so they show small-scale motions within the great equatorial jet-stream; in the fourth sector, the maps are four rotations apart.  The large dark formations on NEBs are stationary in this longitude system, but note the faster (leftward) flow of the SEBn, and the slower (rightward) flow on the equator.  Small-scale features of interest include:

--A series of closely spaced waves on the equator at L1 ~ 110-130, moving with the slow equatorial flow;

--Complex motions in and around some of the NEBs dark formations, including possible anticlockwise flow of streaks in the EZ on the Sp. edge of formations near L1 ~ 240 and 295;

--Possible faster (leftward) motion of a bright streak on the NEBs edge at L1 ~ 15, but no widespread faster motion at this latitude.  (Apparent shift of a small, very bright spot at L1 = 129 is more likely due to multiple short-lived clouds, as images before and after (by M. Kardasis and P. Edwards) show no continuing motion.) 

Whereas the animated maps are simply a visual display of the planet’s winds, the same data can be used to measure the zonal wind profile.  Marco Vedovato has done this with two pairs of images, on Feb.21-22 and on March 6-7: each pair were taken by Olivetti and by Go, 20 hours apart.  His ZWP is shown here (plotted as wind speed in System III).  The two fastest jets are the NTBs jet, 148 (±1) m/s, and the SEBn jet, 146 (±1) m/s.



John H. Rogers, Ph.D.
Jupiter Section Director,
British Astronomical Association

John H. Rogers, Ph.D. Jupiter Section Director,
British Astronomical Association