Astroblog

Evening sky on Sunday February 8 looking north-east as seen from Adelaide at 23:00 ACDST showing Jupiter.  The inset shows Jupiter's Moons at 23:00  on the 2nd. Jupiter is the brightest object above the north-eastern horizon. Similar views will be seen elsewhere at equivalent local times (click to embiggen).

Opposition of a planet from Earth's perspective is when a planet is directly opposite the sun  as seen from Earth. At this time the planet is at its biggest and brightest as seen from Earth (well, its a bit more complicated than that but bear with me).

Jupiter was at opposition on  February 7... at 4am. So go outside and have a look tonight. Jupiter's magnitude will stay around -2.6 (being the brightest object in the sky once Venus has set) for a week, and when it drops too magnitude -2.5, you will need good eyesight and a practised eye to notice the difference.

Unlike Mars, Jupiter's diameter will not change sufficiently to be different in any but the most high end telescopes for many weeks. Last night Jupiter was 45.3 arc seconds in diameter, tonight is is 45.29 arc seconds.

Jupiter is now visible all night long, rising in the east as Venus sets in the west. Easily visible in the evening as the brightest object in the north-eastern skies, it is best for telescopic views, being high enough above the horizon murk and turbulence, for around 11 pm local time on. It is highest around 1 am local daylight saving time (midnight local standard time) above the northern horizon.

Aside from its obvious brightness, Jupiter is easy to find as it is close to the bright star Regulus, the brightest star in the constellation of Leo.  Regulus forms the handle of the hook-shaped asterism of the sickle of Leo.

The following ephemeris is for ACDST, but can be easily converted to local time. Ast Twi is astronomical twilight, when the sky is finally dark, rise, set are obvious and transit is when the planet is due north.

Date         Ast Twi Rise     Set      Transit  Diam " Mag 
07 Feb 2015 21:52:09 20:12:50 06:45:54 01:31:33 45.30 -2.6 
08 Feb 2015 21:50:53 20:08:31 06:41:19 01:27:06 45.29 -2.6 
09 Feb 2015 21:49:35 20:04:11 06:36:44 01:22:39 45.28 -2.6 
10 Feb 2015 21:48:17 19:59:52 06:32:09 01:18:12 45.27 -2.6 
11 Feb 2015 21:46:58 19:55:32 06:27:34 01:13:44 45.26 -2.6 
12 Feb 2015 21:45:37 19:51:13 06:22:59 01:09:17 45.24 -2.6 
13 Feb 2015 21:44:16 19:46:53 06:18:24 01:04:50 45.22 -2.6 
14 Feb 2015 21:42:54 19:42:34 06:13:50 01:00:23 45.19 -2.6 
15 Feb 2015 21:41:31 19:38:15 06:09:16 00:55:57 45.16 -2.5 
16 Feb 2015 21:40:08 19:33:56 06:04:42 00:51:30 45.13 -2.5 
17 Feb 2015 21:38:43 19:29:37 06:00:08 00:47:04 45.10 -2.5 
18 Feb 2015 21:37:18 19:25:18 05:55:35 00:42:37 45.06 -2.5 
19 Feb 2015 21:35:53 19:20:59 05:51:02 00:38:11 45.02 -2.5 
20 Feb 2015 21:34:26 19:16:41 05:46:29 00:33:46 44.97 -2.5 
21 Feb 2015 21:33:00 19:12:23 05:41:57 00:29:20 44.93 -2.5 
22 Feb 2015 21:31:32 19:08:04 05:37:25 00:24:55 44.88 -2.5 
23 Feb 2015 21:30:04 19:03:47 05:32:53 00:20:30 44.82 -2.5 
24 Feb 2015 21:28:36 18:59:29 05:28:22 00:16:06 44.77 -2.5 
25 Feb 2015 21:27:07 18:55:12 05:23:51 00:11:42 44.71 -2.5 
26 Feb 2015 21:25:38 18:50:55 05:19:21 00:07:18 44.65 -2.5 
27 Feb 2015 21:24:09 18:46:38 05:14:51 00:02:54 44.59 -2.5 

The Moons of Jupiter are easily seen in binoculars or even a small telescope, and you can see them winking out as they go into eclipse. In larger telescopes, you can see  them (and sometimes their shadows) cross the face of Jupiter. The Great Red Spot (more pale salmon now) can been seen too. Times of notable Jupiter events and when the great red spot is in the middle of the face of Jupiter are given below in AEDST (subtract an hour for AEST, half an hour for ACDST etc.)
 

Mon	9	Feb	0:35	GRS: Crosses Central Meridian	
Mon	9	Feb	20:26	GRS: Crosses Central Meridian	
Mon	9	Feb	23:52	Gan: Transit Begins               T	
Tue	10	Feb	0:09	Gan: Shadow Transit Begins        ST	
Tue	10	Feb	3:30	Gan: Transit Ends                 S	
Tue	10	Feb	3:48	Gan: Shadow Transit Ends	
Tue	10	Feb	6:22	GRS: Crosses Central Meridian	
Wed	11	Feb	2:13	GRS: Crosses Central Meridian	
Wed	11	Feb	22:04	GRS: Crosses Central Meridian	
Thu	12	Feb	5:29	Io : Disappears into Occultation	
Fri	13	Feb	2:39	Io : Transit Begins               T	
Fri	13	Feb	2:48	Io : Shadow Transit Begins        ST	
Fri	13	Feb	3:51	GRS: Crosses Central Meridian	
Fri	13	Feb	4:57	Io : Transit Ends                 S	
Fri	13	Feb	5:06	Io : Shadow Transit Ends	
Fri	13	Feb	6:04	Eur: Disappears into Occultation	
Fri	13	Feb	23:42	GRS: Crosses Central Meridian	
Fri	13	Feb	23:55	Io : Disappears into Occultation	
Sat	14	Feb	2:24	Io : Reappears from Eclipse	
Sat	14	Feb	21:05	Io : Transit Begins               T	
Sat	14	Feb	21:17	Io : Shadow Transit Begins        ST	
Sat	14	Feb	23:23	Io : Transit Ends                 S	
Sat	14	Feb	23:34	Io : Shadow Transit Ends	
Sun	15	Feb	0:53	Eur: Transit Begins               T	
Sun	15	Feb	1:17	Eur: Shadow Transit Begins        ST	
Sun	15	Feb	3:48	Eur: Transit Ends                 S	
Sun	15	Feb	4:12	Eur: Shadow Transit Ends	
Sun	15	Feb	5:29	GRS: Crosses Central Meridian	
Sun	15	Feb	20:53	Io : Reappears from Eclipse	
Mon	16	Feb	1:20	GRS: Crosses Central Meridian	
Mon	16	Feb	21:11	GRS: Crosses Central Meridian	
Mon	16	Feb	22:32	Eur: Reappears from Eclipse	
Tue	17	Feb	3:08	Gan: Transit Begins               T	
Tue	17	Feb	4:08	Gan: Shadow Transit Begins        ST	
Wed	18	Feb	2:58	GRS: Crosses Central Meridian	
Wed	18	Feb	20:44	Cal: Reappears from Eclipse	
Wed	18	Feb	22:49	GRS: Crosses Central Meridian	
Fri	20	Feb	4:23	Io : Transit Begins               T	
Fri	20	Feb	4:36	GRS: Crosses Central Meridian	
Fri	20	Feb	4:42	Io : Shadow Transit Begins        ST	
Fri	20	Feb	21:51	Gan: Reappears from Eclipse	
Sat	21	Feb	0:27	GRS: Crosses Central Meridian	
Sat	21	Feb	1:40	Io : Disappears into Occultation	
Sat	21	Feb	4:19	Io : Reappears from Eclipse	
Sat	21	Feb	20:19	GRS: Crosses Central Meridian	
Sat	21	Feb	22:49	Io : Transit Begins               T	
Sat	21	Feb	23:11	Io : Shadow Transit Begins        ST	
Sun	22	Feb	1:07	Io : Transit Ends                 S	
Sun	22	Feb	1:28	Io : Shadow Transit Ends	
Sun	22	Feb	3:09	Eur: Transit Begins               T	
Sun	22	Feb	3:54	Eur: Shadow Transit Begins        ST	
Sun	22	Feb	22:47	Io : Reappears from Eclipse	
Mon	23	Feb	2:05	GRS: Crosses Central Meridian	
Mon	23	Feb	21:25	Eur: Disappears into Occultation	
Mon	23	Feb	21:57	GRS: Crosses Central Meridian	
Tue	24	Feb	1:06	Eur: Reappears from Eclipse	
Wed	25	Feb	3:44	GRS: Crosses Central Meridian	
Wed	25	Feb	20:07	Eur: Shadow Transit Ends	
Wed	25	Feb	23:35	GRS: Crosses Central Meridian	
Thu	26	Feb	21:44	Cal: Transit Begins               T	
Fri	27	Feb	2:12	Cal: Shadow Transit Begins        ST	
Fri	27	Feb	2:29	Cal: Transit Ends                 S	
Fri	27	Feb	20:08	Gan: Disappears into Occultation	
Sat	28	Feb	1:13	GRS: Crosses Central Meridian	
Sat	28	Feb	1:50	Gan: Reappears from Eclipse	
Sat	28	Feb	3:24	Io : Disappears into Occultation	
Sat	28	Feb	21:04	GRS: Crosses Central Meridian	

Labels: binocular, Jupiter, Opposition, telescope, unaided eye