Wednesday, February 29, 2012

The Rare Triple Eclipse of Jupiter

Written by Matthew Winter 

On March 28, 2004, The Hubble Space Telescope snapped an amazing picture of the transit of two of Jupiter’s confirmed sixty-six moons, and the shadows of three of them, resulting in an image of which shows the spontaneous phenomena capable of this planet’s lunar bodies. At first glances, Jupiter appears to be a brightly colored orb, with hues parallel to a pastel or neon painting, with five different spots placed randomly about its northern hemisphere; its altered coloring was result of being taken by Hubble’s Near Infrared Camera and Multi-Object Spectrometer, instead of photographing in the visible spectrum. The image is comprised of three of these near-infrared photographs, producing the different shades of color visible—yellow indicates high cloud cover, red indicates low, and blue, even lower cloud cover. 

 Although phenomena such as the event captured in the image, finding Jupiter in the night sky is no hard task and can be especially bight when at opposition. But, there are no definite set of celestial coordinates in locating this planet, because of its ever-changing position in the night sky. According to ephemerides however, computers have been able to plot the course of Jupiter on timescales greater than one millennium, so locating and charting the planet’s position will never be tedious work. For the end of February 2012, Jupiter will be visible in the south-southwestern sky just after sunset, at the averaged Right Ascension of 2h 19m and the Declination of + 12° 53’. Again, phenomena seen in the image are rare and do not occur often.

Upon looking at the image, you might inquire of when such an event will occur on Jupiter. Although it might seem very rare that three moons cast their shadow while two transit, rather it is not. This event is called a Jovian Dual-Transit, as it incorporates two different moons, in this case Io and Ganymede, simultaneously transit the surface. But because of the two shadows also cast by these two moons, it is more appropriately named A Jovian Dual-Shadow Transit where two moons transit and cast shadows. The third shadow, consequently given by Callisto, not pictured in the image, makes this event even more complex—and it is quite spectacular that Hubble was in the right place at the right time to photograph such a spectacle. In describing it, however, it is not troublesome to locate the three, distinct shadows of the three moons notwithstanding Io and Ganymede, which seem to be camouflaged in with Jupiter’s pallid colors. Io sits nearly in the center of the image, in white, opposed to its visible color of hazy yellow or golden. Ganymede is to the upper right of Io, and is pale blue; Ganymede is visibly the color of our Moon, a flushed grey.

Whereas a beautiful image of Jupiter with three shadows and two moons cresting its upper hemisphere is rather somber and dreamy, to astronomers, this image allowed them to attempt a new technique of imaging, which succeeded in the end. Attempting to capture images of Jupiter and its moon is rather difficult, especially when completely focused on an object. Because Jupiter moves quickly across Hubble’s telescope view, it was necessary to take a rapid succession of images, before Jupiter moved out of the telescope’s lenses.

Of course, Hubble has the equipment to track an object far away and hold for hours; Jupiter is much closer to earth than distant galaxies, so things tend to move quicker than you would think—and when locked onto it, the sharpness of the image was distorted, creating a blurry picture, not fit to be called a Hubble image. So, astronomers tried, for the purpose of creating a sharper, neater image, to speed up Hubble’s tracking system, resulting in the ‘slower’ movement of Jupiter through the telescope, which in return allowed Hubble to take such a fine image of its moon in such phenomena.

In conclusion, it is important to see that not only did this image of Jupiter’s rare triple ‘eclipse’ phenomena helped astronomers for the better of planetary images (in that, the slowing down of Hubble’s tracking system made clearer photographs of planets from earth), but also to record a rare event for the wonder and mystery of extraplanetary phenomena—other planets do indeed experience eclipses and transits!

With Information from (Accessed February 24 & 27 2012):

Sunday, January 22, 2012

Understanding Jovian Eclipses

[This article concerns Jovian eclipses, not transits. Although a Jovian eclipse can mean the same thing as a transit in this sense, this article talks about the disappearance and reappearance of the Jovian moons, not the transit of Jupiter’s surface.]

Considered the most intriguing and fascinating astronomical phenomena yet, the eclipse is highly acclaimed not just here on earth, but also in the rest of our solar-system. When a celestial body passes into the shadow of another body, preferably larger; or an object casts a shadow upon another, an eclipse is formed. From there, the term ‘eclipse’ can be forwarded into two separate definitions: the solar eclipse, or the lunar eclipse. When the Moon passes in front of the Sun, respectively on the ecliptic, a shadow is cast upon the earth; a solar eclipse is formed. When the Moon passes into either the umbral or penumbral shadow of the earth, again respectively on the ecliptic; a lunar eclipse occurs. Although these definitions discreetly define actions in a terrestrial sense, these same exact phenomena occur on the other seven planets in our vast solar-system, but with another name.

When an object passes into the shadow cone of Jupiter, it disappears from view (note the striped moon to represent being eclipsed instead of being solid colored, not eclipsed)
The Jovian Eclipse is perhaps one of the most unique extraterrestrial happenings, for it involves one of the many Jovian moons, mainly the Galilean moons, Jupiter, and the Sun; rather just the Moon and earth. Because a solar eclipse and a lunar eclipse have terrestrial definitions and terms, therefore, a Jovian Eclipse is defined as “the passing of a Jovian moon into the shadow-cone of Jupiter where it is eclipsed out of sight, until reappearing.” These eclipses can be total, in which the eclipsed moon is eclipsed indefinitely; or partial, where the eclipsed moon is partially eclipsed. But, you must make note that the Galilean moons (the four most famous moons, which we do know to eclipse) have very little orbital inclinations. With Io, having an inclination of 0.050º, Europa with 0.471º, Ganymede with 0.204º, and Callisto with 0.205º, it is doubted that partial eclipses can occur, because each of the moons’ orbits are so perfectly aligned with Jupiter’s equator; therefore, no partial eclipses. Aside from the types of Jovian eclipses that occur, series of eclipses take place, nevertheless imitating ‘Saros’ here on the earth. Because the moons that do eclipse are rather diminutive compared to Jupiter itself, an observer on Jupiter would not notice much, so a Jovian observer would consider a Jovian eclipse as a phenomena of theoretical interest, or something unimportant to note. Nevertheless, the Jovian moons’ ‘Saros’ is pure academic interest as well.

Seeing a Galilean moon eclipse is an enchanting experience you won’t forget. But, certain requirements are needed for you to observe one; it’s hard for Jupiter to produce such key-viewing times, like the one in 1999. “Jupiter and Saturn returned to the sky in autumn of that year; Jupiter was at its best to view in a long time. Jupiter and its moons were easily observed with a small telescope, and two of three phenomena could easily be seen. Transits and occultations were easy to see, but not so much for eclipses. That’s what makes eclipses so amazing,” Matthew Winter writes from Astronomical Events: Eclipses, Transits, Occultations, and Conjunctions. In order for Jupiter to produce a good eclipse viewing season, it first must be at either eastern or western quadrature. Quadrature is simply a fancy term for the time when a planet forms a right triangle with the earth and Sun. Western Quadrature occurs when the planet is towards the west of earth, and Eastern Quadrature is vice versa. Jupiter forms a twelve degree angle on its end, while the ninety degree angle is on earth’s end. Then, we are able to see the moons eclipse in and out of Jupiter’s shadow cone, rather than at opposition. At opposition, when the earth, Sun, and the planet of note (Jupiter) are all aligned in a straight line, Jupiter’s shadow cone is behind the planet, making eclipses invisible from earth. Precise timings are location is everything in viewing a Jovian eclipse. “Because its shadow cast is very magnificent, when a Galilean moon passes behind it, it disappears completely from view, but has not been occulted. As well as that, because the shadow cast is so steep, the Galilean moons may be viewed entering and exiting the shadow on the same side of the planet!,” from Astronomical Events: Eclipses, Transits, Occultations, and Conjunctions.

Jupiter’s shadow cone is brought into our view at quadrature, it’s not at opposition, which is when Jupiter would make the earth, Sun, and Jupiter in a straight line.
August 1, 2011 brings us to Jupiter’s Western Qudarature, which is a key time to view these events. Around west quadrature, Jupiter rises beautifully in the east around midnight and shines high up at dawn. But mind you, Jupiter takes over eight years to orbit, so returning to Eastern Quadrature will take a few years, so patience is a good aspect in waiting for the return of the Jovian eclipses.  Returning to 1999, Capitol Skies (the newsletter of the Madison Astronomical Society) tells us this about the Jovian eclipses during that epic season. “Jupiter provides a virtual smorgasbord of events to watch. Of the three events, eclipses are by far the most scientifically interesting, because the timing of the precise disappearances and reappearances of the moons can be used to calculate orbital elements of the moons. For this reason, precise timings of the Galilean moon eclipses are sought by the Association of Lunar and Planetary Observers (ALPO).” You can visit a myriad of online resources to locate the times of Jovian eclipses, for what more is there to miss? A moon may be eclipsing now!

Here is a basic explanatory site of Jupiter’s phenomena:

Galilean moons simulator from the Transits Page (click ‘now’ for most current events):

[To download the Word Document of this story, come to this page where it can be downloaded.] 

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"

Thursday, January 12, 2012

Single Phenomena 2012: The Truth Behind Them

What are single phenomena of Jupiter's satellites and how can this occur? These commonly asked questions about single phenomena are inevitable to every person, and should be all summed up in this article.  Single phenomena are beautiful flourishes of every Jovian event calendar, and should remain that way, for their intrinsic values are not that complex at all. Appropriately defined, single phenomena of Jupiter's moon is "an event of the Galilean moons when one moon is the only one visible, the others either occulted or in transit." And this will occur eleven times, divided into two periods, in 2012.

The first period of single phenomena is in January, with five events in a little over two weeks. Callisto (as for all of the 2012 single phenomena) is the only moon present (partially becasue its orbit is so big, rarely it is in transit or in occultation), while the other three, Io, Europa, and Ganymede are not. The next period takes place in the end of July and is finished around Mid-August. These comprise the rest (six) of the phenomena.
Below is a table of these eleven events for 2012.

You can configure what these would appear to be at the Galilean Moons Simulator; just plug in the time and date into the simulation. NOTE: The times in the chart are in TDT. Galilean Moons Simulator computes only in UTC. Conversion: (TDT is about a minute or two ahead of UTC).
With references from

Tuesday, January 10, 2012

Jovian Dual-Shadow Transit of January 11, 2012

2012. It is a new year, and what better other way is it to start it off with another dual-shadow transit of Ganymede and Europa!? Although 2012 has less dual-transits than 2011 had, hopefully this year will exceed your expectation on astronomy and Jovian-dual transits. We start the year with a dual-shadow transit of Europa and Ganymede on January 11, 2012 at 4:41 UT. Io will not come into the picture again until March 23; Europa and Ganymede will dual-shadow transit three times in January (the 11, 18 & 25). Callisto does not take any part this year, as it did on January 25, 2011.

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), the January 11 dual-shadow transit is one of the shortest transits of the year, with Europa and Ganymede themselves transiting for 00:23 minutes; both shadows of these moons transit for 00:20 minutes, though. This occurs over the time frame of 06:24 to 06:47 UT for dual-transit, and 06:25 to 06:25 UT for dual-shadow transit. If the skies are clear on the Eastern Seaboard, this event will take place at 1:24 am EST and end on 1:47 am EST. The last two transits (October 24 and 31) were not visible; at last there is one that is, needless to consider others that are coming!

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-

January 10, 2012 at 21:24 UT. You can see that Ganymede and Europa are ready to transit 1/11 at approx. 4:30 UT!

Here Comes Io! Although the above pictures are cropped, Io is in them to the right of Jupiter. Now, it has come in full view as it ascends into occultation by Jupiter itself. Ganymede and Io conjunct right before this occurs, as you can see. 

2012-Jan-11 16:54 Conjunction of Europa and Ganymede [124.5" W; 6.4" S]
You may notice that Europa and Ganymede conjunct twice today (at 16:54 and 19:33). This is becasue of their orbits. They are, in the above picture, practically at the end of their 'orbit,' and will reverse to come behind Jupiter. Doing this, they conjunct again.


2012-Jan-11 04:39 Transit Ingress of Ganymede
2012-Jan-11 04:41 Shadow Transit Ingress of Ganymede
2012-Jan-11 05:05 Transit of Great Red Spot
2012-Jan-11 05:45 Inferior conjunction of Ganymede
2012-Jan-11 06:24 Transit Ingress of Europa (Double Transit Begin)
2012-Jan-11 06:25 Shadow Transit Ingress of Europa (Double Shadow Transit Begin)
2012-Jan-11 06:45 Shadow Transit Egress of Ganymede (Double Shadow Transit End)
2012-Jan-11 06:47 Transit Egress of Ganymede (Double Transit End)
2012-Jan-11 07:29 Conjunction of Io and Ganymede [19.9" W; 22.2" S]
2012-Jan-11 07:29 Occultation Disappearance of Io
2012-Jan-11 07:40 Inferior conjunction of Europa
2012-Jan-11 08:52 Shadow Transit Egress of Europa
2012-Jan-11 08:53 Transit Egress of Europa
2012-Jan-11 09:39 Eclipse Reappearance of Io
2012-Jan-11 15:00 Transit of Great Red Spot
2012-Jan-11 16:54 Conjunction of Europa and Ganymede [124.5" W; 6.4" S]
2012-Jan-11 19:08 Eastern Elongation of Io, 123.4"
2012-Jan-11 19:33 Conjunction of Europa and Ganymede [151.7" W; 6.9" S]

Saturday, January 7, 2012

2012 Calculations of Dual-Transits are Finally Here!

Thanks to the Transits Page, the 2012 results are finally here! "During 2012 Earth experiences 18 dual satellite and 17 dual shadow transits of Galilean satellites of Jupiter," opens the document. (For comparison, 2011 has 18 dual-satellite but 20 dual shadow.)

Longest Dual Transit = 2012 Jul 28 = 02h 02m (Io and Europa)
Shortest Dual Transit = 2012 Jul 10 = 00h 00m (Io and Europa)

Longest Dual Shadow Transit = 2012 Jul 28 = 02h 01m (Io and Ganymede)
Shortest Dual Shadow Transit = 2012 Aug 18 = 00h 08m (Io and Europa)

Dual Transits

Begin           End               Duration           Satellites

Jan-11 06:24 Jan-11 06:47 00:23 Europa Ganymede
Jan-18 08:57 Jan-18 10:45 01:48 Europa Ganymede
Jan-25 12:38 Jan-25 14:03 01:25 Europa Ganymede
Mar-23 00:30 Mar-23 01:08 00:38 Io Ganymede
Mar-30 03:24 Mar-30 04:43 01:19 Io Ganymede
Jul-10 19:54 Jul-10 19:54 00:00 Io Europa
Jul-14 08:54 Jul-14 09:19 00:25 Io Europa
Jul-17 21:53 Jul-17 22:42 00:49 Io Europa
Jul-21 10:53 Jul-21 12:06 01:13 Io Europa
Jul-24 23:52 Jul-25 01:30 01:38 Io Europa
Jul-28 12:51 Jul-28 14:53 02:02 Io Europa
Jul-30 07:26 Jul-30 09:21 01:55 Io Ganymede
Aug-01 01:52 Aug-01 04:00 02:08 Io Europa
Aug-04 15:16 Aug-04 16:59 01:43 Io Europa
Aug-08 04:37 Aug-08 05:57 01:20 Io Europa
Aug-11 18:00 Aug-11 18:56 00:56 Io Europa
Aug-15 07:21 Aug-15 07:54 00:33 Io Europa
Aug-18 20:43 Aug-18 20:52 00:09 Io Europa

Dual Shadow Transits

Begin        End           Duration       Satellites

Jan-11 06:25 Jan-11 06:45 00:20 Europa Ganymede
Jan-18 08:58 Jan-18 10:43 01:45 Europa Ganymede
Jan-25 12:40 Jan-25 14:02 01:22 Europa Ganymede
Mar-23 00:30 Mar-23 01:06 00:36 Io Ganymede
Mar-30 03:27 Mar-30 04:43 01:16 Io Ganymede
Jul-14 08:54 Jul-14 09:18 00:24 Io Europa
Jul-17 21:54 Jul-17 22:41 00:47 Io Europa
Jul-21 10:53 Jul-21 12:06 01:13 Io Europa
Jul-24 23:52 Jul-25 01:29 01:37 Io Europa
Jul-28 12:51 Jul-28 14:52 02:01 Io Europa
Jul-30 07:29 Jul-30 09:19 01:50 Io Ganymede
Aug-01 01:53 Aug-01 03:59 02:06 Io Europa
Aug-04 15:16 Aug-04 16:58 01:42 Io Europa
Aug-08 04:38 Aug-08 05:57 01:19 Io Europa
Aug-11 18:01 Aug-11 18:55 00:54 Io Europa
Aug-15 07:22 Aug-15 07:53 00:31 Io Europa
Aug-18 20:43 Aug-18 20:51 00:08 Io Europa

Sunday, November 20, 2011

Wa†er On Europa? Europa Becomes the Fame Planet

It's one of our own moons - Europa, which has become The Fame Planet. Jupiter should be proud to present one of it's own as a possible suspect for the presence of water on such a distant orb of light. After data was collected from NASA planetary mission, it appears that a body of water was found underneath the icy surface of the moon, which astronomers believe that there is a "significant exchange" between Europa's frigid, icy top and the icy ocean beneath it. Of course, this brought in NASA's interest, becasue they are always trying to find extraterrestrial life. NASA says that this could be a "potential habitat" for more life, and one NASA scientist has raced to conclusions. Listen to this, written in an article by Thaindian News:
One Scientist has suggested that at least three million tons of fish-like creatures could theoretically live and breathe under Jupiter’s moon Europa’s global ocean. “I’d be shocked if no life existed on Europa,” said Timothy Shank, a deep-sea molecular ecologist. 
Although this is my opinion, I believe that this scientist has raced to conclusions! This ocean, though, has been known for a while of its "water," but new insights have been found after recent research. It has been found that "the extraterrestrial ocean is currently being fed more than a hundred times more oxygen than previous models had suggested...," meaning to us that life could be possible. [Although the information presented above is from 2009, the same resolutions have been derived from this past week's articles].

Found on Washington Post
 "Washington, Nov 17 (IANS) NASA’s Galileo spacecraft has found evidence of water beneath the icy surface of Jupiter’s moon Europa, researchers said." “Now, we see evidence that it’s a thick ice shell that can mix vigorously and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable,” said Britney Schmidt, lead author of the study and fellow at the Institute for Geophysics, University of Texas, Austin. “If Europa is habitable, we need to get material from the surface down into the deep interior, down into the ocean,” Schmidt said. Because Europa is a cold, icy moon, freezing and refreezing of ice takes place constantly, along with melting. “It’s a vigorous process,” Schmidt said. “Material is getting thrown around. Icebergs are flipping over. Brines are going up and coming back down.”

Washington Post

Credit: NASA