It's bigger than we ever hoped. The impacts of Comet Shoemaker-Levy 9 are creating more fireworks on Jupiter than anyone expected.
Infrared telescopes around the world have been imaging stupendous fireballs looming up over Jupiter's limb. And black markings at some of the impact sites are easily visible in amateur telescopes.
On Sunday night many U.S. amateurs watched the growing black spot from Impact A creep around Jupiter, followed by the smaller black spot from Impact C trailing about 40 degrees behind.
That was just the warmup. On Monday amateurs around the world reported the huge black marks of G and H in telescopes as small as 2.4 or 3 inches aperture. The Hubble Space Telescope showed them in stunning, complex detail.
The impact zone is in Jupiter's far southern latitudes, normally a dull area, making them easy to recognize.
The Hubble Space Telescope team has announced Jovian longitudes for A through E. These positions suggest the impacts themselves came 5 to 14 minutes late.
Based on that, here are new times for the remaining impacts. These include the 43 minutes of light time between Jupiter and Earth and are given in Pacific Daylight Time.
Fragment Date PDT H July 18 12:36 p.m. PDT K July 19 3:28 a.m. L 3:19 p.m. N July 20 3:30 a.m. P2 8:22 a.m. Q2 12:42 p.m. Q1 1:09 p.m. R 10:36 p.m. S July 21 8:20 a.m. T 11:14 a.m. U 2:58 p.m. V 9:27 p.m. W July 22 1:08 a.m.
Now, here are tentative System II longitudes of where to look for black spots.
Impact A, 116 degrees. B, 7 degrees. C, 156. D, 327. E, 82. Those first five were from positions measured by Hubble. F, 68. G, the big one, 319. H, another biggie, 32. K, 211. L, 279. N, 361. P2, 179. Q2, 334. Q1, 350. R, 332. S, 325. T, 72. U, 207. V, 81. W, 213.
Those are system-2 longitudes used by visual observers; not the system-3 values circulating from the professional community.
To find longitudes on Jupiter at any observing time, see the July Sky & Telescope, page 33. Jupiter rotates every 9 hours 56 minutes.