Tuesday, January 17, 2012

Jovian Dual-Shadow Transit for January 18, 2012

In perfect resonance, this January, Ganymede and Europa will dual-shadow transit three times, each a perfect interval apart: one week. Last Wednesday night (approx. 1:30 am EST), the moons will transit, and again, on the 18, the will again; finishing up a week from this transit (the 25). Hopefully, viewing conditions will be perfect tonight, as Wednesday, January 18, 2012's transit will be the longest, in totality, 1:48 hours long, for dual transit, and 1:45 hours long for dual-shadow transit. This is much more "like" a dual-transit, as last's weeks was dull; although no dual-shadow transits are dull, mind you!

According to Simultaneous Transits of Galilean satellites and their shadows across Jupiter during 2012, a paper that lists each of dual-transit phenomena in full (can be accessed here), everything starts at 8:57 UT (3:57 am EST) and ends 10:45 UT (5:45 EST). Although the end of the event might be lost in the morning sunrise, nevertheless the beginning is worth seeing.

Note: If something on the picture reads "Shadow Ingress (or Egress)," and no shadow is seen, this is particularly because of Jupiter's position at this time. The shadows will not be visible until Jupiter moves into another position. 

-all pictures below are credit The Transit's Page, Galilean Moons Simulator; text entered by myself-

2012-Jan-25 09:26 Conjunction of Europa and Ganymede [46.8" E; 6.2" S]


2012-Jan-18 00:23 Western Elongation of Callisto, 537.8"
2012-Jan-18 05:53 Transit of Great Red Spot
2012-Jan-18 08:36 Transit Ingress of Ganymede
2012-Jan-18 08:38 Shadow Transit Ingress of Ganymede
2012-Jan-18 08:57 Transit Ingress of Europa (Double Transit Begin)
2012-Jan-18 08:58 Shadow Transit Ingress of Europa (Double Shadow Transit Begin)
2012-Jan-18 09:23 Occultation Disappearance of Io
2012-Jan-18 09:43 Inferior conjunction of Ganymede
2012-Jan-18 10:14 Inferior conjunction of Europa
2012-Jan-18 10:43 Shadow Transit Egress of Ganymede (Double Shadow Transit End)
2012-Jan-18 10:45 Transit Egress of Ganymede (Double Transit End)
2012-Jan-18 11:26 Shadow Transit Egress of Europa
2012-Jan-18 11:27 Transit Egress of Europa
2012-Jan-18 11:33 Eclipse Reappearance of Io
2012-Jan-18 12:12 Conjunction of Europa and Ganymede [28.1" W; 5.8" S]
2012-Jan-18 15:49 Transit of Great Red Spot
2012-Jan-18 21:04 Eastern Elongation of Io, 120.6"

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Credit: NASA