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JEE2014 Call for Observations: 

2014 Predictions:

JEE2014 Call for Observations Power Point:





Special JEE Events Discussion


I (Io)


TJEE – Io Torus Tip Transit



            I transits the tips near the Torus of Io at least once a day. As the orbital plane of the Torus moves closer to edge on in 2014 we should see the amount of extinction deepen at the times when Io is in the Torus at the tips. It turns out that Torus has a wobble and Io itself is not always in the Torus ring, but during the times when Io might be in the Torus ring the extinction should be easily detectable. We have never observed Io at back to back transits of the Torus tip. 2014 would be a great opportunity to document how often Io is in or out of the Torus material. Here is a movie made of the Io torus as observed on 11 November 2000 by the Cassini Space Craft:


            JEE measurements of the atmosphere surrounding Io won’t begin until May 21st 2014. This will give us only about a month before Jupiter is less than 20 degrees elongated from the Sun. But starting at the end of August 2014 when Jupiter emerges from the other side of the Sun’s glare we get multiple opportunities to trace out the atmosphere of Io up to November 2014. During the end of November to most of December Io is in the shadow of Jupiter preventing any JEE events with I in front.



II (Europa)


GJEE – Europa water geysers

Discussion: Embargoed for publication


Now comes the topic of most excitement for 2014, our JEE techniques may, just maybe, just might be detecting some liberated water from the recent discovery that Europa has water geysers at its poles!


Here are some recent articles regarding Europa geysers:


            So please make a special effort to observe all JEE event where Europa is in front. We have one really good event on May 25th from about 13h30m UT to 15h UT. Then as Jupiter emerges from the other side of the Sun starting August 24th all the way to the end of 2014 (and in to 2015) we have dozens of events where a moon skims over the north pole line of sight of Europa. Any one of these could discover another anomalous dip. If the dip is not there one day, is there the next, and not there or is fading the next day we could really start to get some temporal information on the character of these geysers, if in fact we are detecting them. In late October and through the end of 2014 all of the near occultation conjunctions skim 1 Europa radii or less just above the surface of Europa’s polar region where the geyser material would be most dense. This would be the best time to coordinate a JEE observation with a large professional scope to correlate a JEE diming to a possible visibly or spectrally detected geyser.



III (Ganymede)


            JEE events where III is in front are underway very early in 2014 and deepen all the way to the end of 2014. We have no real data history with Ganymede atmospheric measurements. We have a few from 2009 that seemed to not detect much of any dimming around Ganymede as an object passed behind it. But we just need a lot more data to show one way or the other.



IV (Callisto)


            While there are a handful of potential JEE events of IV in front in June, the bulk of those geometries occur starting in August and increase in number and depth towards the end of 2014. We have zero IV in front JEE data so this is highly desired as I cannot make a single assumption on what to expect with these.


Stellar JEE


            On May 4th from 0h55m to 2h04m UT a 9th magnitude star passes within 20 III radii behind III. It would be interesting to try to observe this conjunction for dimming of the star, but to observe this you will likely have to saturate the moons so they cannot be used as a reference light source. However there are a few field star within a 30 minute radius that could certainly be used as a reference. You can find the specific prediction of this in 2014 Star JEE.



JME 2014 (Jovian Mutual Events)


 We have a unique situation in 2014 (and 2015) where the orbital plane of the moons of Jupiter go edge on creating geometries of mutual events where the moons pass in front of each other as well as the shadow of one eclipsing another moon. This happens every 6 years and a special observing program called PHEMU2015 ( has been established by the IMCCE in France. You will notice a dashed line at the bottom of each Quick View Plot representing a 2 radii separation, and any bodies passing closer together than this will experience an occultation where the front moon will block part or all of the back moon’s body. In the case of an occultation you will find a gap in the predicted lightcurves at approximately the start and stop of the occultation, as this region of the photometry will deviate from the extinction region outside of the occultation. Please consider submitting your occultation or eclipse data to the IMCCE PHEMU2015 Campaign.


Version 3 predictions of Jovian Extinction Events will hopefully improve observation planning by highlighting events with the best potential for extinction measurements. To date our data collection has mainly featured measured extinctions where Io (I) or Europa (II) was in front of another moon, or Io suffering self extinction as it transits the tips of the Torus of Io. 2014 gives multiple opportunities to acquire even more of these types of JEE events as well as presenting new opportunities for us to acquire multiple measurements of Ganymede (III) and Callisto (IV).


Note that I have eliminated events using the following applied prediction filtering:


·         If either moon is less than 1 Jupiter radius from the limb of Jupiter where glare from Jupiter might compromise the photometry.

·         If either of the moons involved are in the shadow of Jupiter.

·         All events occurring when Jupiter is less than 20 degrees from the Sun (basically from about the end of June to middle of August 2014).

·         Any geometry for I in front with separations greater than 10 I radii.

·         Any geometries for II, III, IV in front with greater than 20 front moon radii separation.

·         Predicted lightcurves are based on past unfiltered photometric observations.

·         At this time I am only highlighting occultation or conjunction (near occultation) JEE events. There is likely good data to be had with eclipse JEE, but eclipse events present complex lighting situations that are hard to deconvolve from the lightcurve data.


Quick Start information:


To have a quick but comprehensive idea of when and what type of event is occurring the folder 2014 All Quick View can fairly instantly show you what to expect. The plot called 2014JEE_QuickViewPlot_All.png shows the times and geometries of all conjunction (i.e. a near occultation) or occultation JEE events of interest for 2014 in a single page. All of these events are also separated to Quick View Plots for each moon individually. The graphic displays of the Quick View Plots give the UT date in the X axis and the separation in radii of the front moon to a body behind that moon line of sight. The Full Data PDFs provide complete details of an event in 2 minute steps. And in case you want to have access to all of the full data in a table format I have provided this in the Excel file 2014 All sorted full data V3.xls.


You will then find four folders called 2014 I, II, III, or IV in front. In each moon’s folder is a sub folder for every highlighted event for that moon for 2014. Included in a sub folder for each highlighted event is an animated GIF of the moon configurations relative to Jupiter so you can get an idea ahead of time of what moon you want to use for a reference light source. For the moons I and II we have a fairly consistent JEE derived atmospheric model, so in each individual event for I or II in front you will see a predicted lightcurve plot of expected unfiltered magnitude drop of the object behind the front moon based on these models. This can also help you decide what event you want to dedicated time to observing, or even what part of the expected lightcurve occurs when the object is visible for your area. Many of these events require many hours to observe so you may only be able to dedicate time to a portion of an event. (Please keep in mind these are predicted lighcurves to provide a general idea of what can be expected, actual results may vary and thus why we need the data. Also, these lightcurves are based on unfiltered CCD video or streaming imaging data. Filtered observations will be different and are also desired). You will not find a predicted lightcurve for III or IV is in front as we have no working extinction model yet, and it is not even known if extinction will be observed for those two moons. Also in each sub folder of each event I have tried to provide the data for I when it is transiting a Torus Tip. It is important to know this as during those times the light from Io will be generally unreliable as a reference source, or if it is the moon involved in the event the additional potential extinction from Torus material may contribute to any magnitude loss creating a complex lightcurve.



Notes on how to observe


Please read some of the good tips located at


Note that during 2014 I am requesting that anyone with the capability of observing multiple colors to do so, especially if you can observe filtered imaging of different colors at the same time. I am going to personally try to configure my observing to record through a red and a blue or UV filter at the same time. We want to collect as much data at one longer wavelength such as red or IR and one shorter wavelength such as blue or UV. If you can observe in any of those combinations such as R and B, or V and B, or V and UV, etc., this data would be valuable data to validate our current working theory that the photons from the moon passing behind another moon’s atmosphere are scattered by the very small particles bound around the front moon line of sight. For instance with Europa the particles were detected by the Galileo probe to be about 0.6 microns in size. So red photons which have a wavelength greater than this would not be affected by the small molecules, but green and blue light photons have wavelengths smaller than 0.6 microns and could be scattered. Several color data sets we have seem to validate this but we need many more data points to finalize this theory. Please note that unfiltered data is still very welcome, so don’t worry if you do not have filter observing capability. Join the JEE Yahoo Discussion group for more detailed discussions:


Scotty Degenhardt

Santa Fe, NM  USA


Jovian Extinction Event Principle Investigator


JEE2013 Special Events Discussion



Grabbing Europa by the horns!


Early results from the JEE2012 Observing Campaign yielded a surprising new anomaly. While still classified as an anomaly, it is surprisingly repeatable and so far also appears symmetrical. I will propose that by the end of the JEE2013 Campaign this feature will be well defined and no longer classified as an anomaly.


The anomaly for the lack of a better term is horn like spikes in the photometric lightcurve when Europa is in front of a probing light source. In the plot below from 2012-Aug-04 UT we examine A. Scheck’s extinction geo-photometric lightcurve where Europa passed in front of Io line of sight, and Io got within about 13 Europa radii separation from Europa’s body center. When plotting the lightcurve we see that at +/- 7.5 Europa radii a drop of intensity of Io lasted several minutes and at several tenths of a magnitude at the unfiltered wavelengths. To date no real explanation for these dips has been solidly proven. The current controversial working model is that the flux tubes that connect each major Jovian moon to Jupiter is sweeping or attracting dust into dense clumps that are causing brief but deep extinction of light passing through the dust clumps. (I would further propose the zebra pattern at 0 to about -5 Europa radii are also caused by magnetic flux lines bunching up dust). To date we have about five lightcurves that show these “horns” in the photometric lightcurve.



20120804 Scheck IIxI GeoPlot.png



We previously measured detectable extinction out to 20 Europa radii for Europa at its equator. August 2013 through the end of 2013 offer an exciting opportunity to resolve this anomaly as a total of 55 events occur where Europa is in front of a probing lightsource that passes within the 20 Europa radii boundary. Of those conjunctions 39 of those pass within 16 Europa radii where the 2012-Aug-04 A. Scheck lightcurve was taken. The closest minima will be only 7 Europa radii (thus 6 Europa radii from Europa’s surface), very convenient given that we are still a full year away from that start of the Jovian Mutual Event Season when the moon orbit’s are edge on enough to cause occultations.






It would be very beneficial to have enough global coverage to get most, if not all of these conjunctions captured photometrically. Even if only half of these are acquired the opportunity exists to then trace out the anomaly from near Europa’s surface to 20 Europa radii and eventually beyond. Given the short duration of these dips it is highly recommended that photometric data be acquired through either video camera imaging, or with continually streaming images from a standard CCD in a video like mode. The full width half max of these dips are on the order of a few minutes. So taking a single CCD image every 5ish minutes cadence would likely result in one completely missing the trend. The JEE effort has officially adopted the Imaging Source DMK 21AU618.AS USB video camera as the most inexpensive video camera with the highest spectral sensitivity, ease of use, and highest photographic resolution. This camera will enable our future efforts of Saturn Extinction Events and other yet to be identified venues. If you already own a Watec or other video camera that allows you to manually control your exposures to prevent target objects from being over or under exposed then you are set for proper equipment. Visit the Observing Tips JEE page or ask questions on our JEE_Talk Yahoo Discussion Group if you need help planning observations:


Please download the Special Events Zip file to get this discussion and predictions and mark your observing calendars for those events that occur in your time zone.


JEE2013 Call for Observers

    As Jupiter’s orbit ever so slowly closes towards edge on in late 2014, JEE events will have ever smaller separations between the Jovian moon conjunctions and near eclipses. JEE2012 showed us once again what all past observing Campaigns have shown, we are in unchartered territory and surprises in our lightcurves abound and need much more additional data.

    2013 opens up with what I like to call the “Quarter of Io”. The geometry of the conjunctions of Io and Europa are such that starting in January and leading up to the April 4th UT conjunction of I-II the separations will get so close that we may skim the upper atmosphere of Io with extinction measurements. Using Europa as the probe for Io’s surrounding dust and gas field we will look for dimming as Europa passes behind Io line of sight to within 8 Io radii where we measured Io’s extinctive part of its atmosphere to in IAEP2009 and JEE2010. Add to that the excitement of JEE2012 showing us all new anomalies that may be material streaming through the flux tubes of moons connected to Jupiter’s poles, we may get repeated measurements of this new anomaly with this fortuitous close geometry. Pay special attention in the predictions for all events where I is in front and II is in back.

    After the April 4th I-II conjunction I and II begin separating in distance of their closest approach with each conjunction until later when Jupiter’s orbit closes more. But then the Summer of 2013 belongs to Europa. Starting in early June Europa will be in front with Io in back being the probe for Europa’s dust and gas, and the conjunctions will get within 20 Europa radii where we measured Europa’s equatorial extinction to extend to. Starting in early June 2013 pay special attention in the predictions for all events where II is in front and I is in back.

    Towards the end of 2013 every conjunction gets closer and closer until September of 2014 when the bodies of the moons actually occult each other and JEE data will be plentiful with each event. Record any part you can within a JEE event window of opportunity. Place high priority on events with smaller arc seconds of separation, especially when those separations are less than 20”. These measurements outside of occultations as the bodies are further apart are still important for placing outer limits and boundaries on Jovian dust and gas distribution.

    Remember also that Io transits its Torus Tip once a day and suffers self extinction during those tip transits.

    You can get the latest discussions on JEE work on the new Yahoo JEE_Talk Discussion Group:

    Predictions through 2014, past results, and additional information about how to observe and submit data of JEE can be found at:



***JEE2012 Extended Call for Observers***


   The initial JEE2012 Observing Campaign yielded new and repeatable anomalies. During this Campaign we were probing the outer limits of the atmosphere of Europa. We found initially that the expected extinction rates based on a 1st order assumption of a spherical distribution of dust did not exist in the north polar region of Europa. Instead of finding a linear type of extinction rate there were spikes in the dimming of the moon passing behind Europa that at the moment appear to potentially be caused by the walls of the flux tube(s) that connect Jupiter to Europa. In an effort to verify if the source of these brief dimming are from the walls of the flux tubes I have generated predictions through 2014 of what I am now calling “JEE Window of Opportunities”. Using JPL ephemeris I have created a macro that tells me when any of the four major Jovian moons are within 30 radii of the moon closest to earth (i.e. in front) at the time of this conjunction. Since the orbits of the Jovian moon are not edge on until 2014 each of these conjunctions will allow us to trace out the flow tubes via extinction from far above each moon to the equator of each moon as we get close to edge on in. Then as the orbit of the moons opens up in the opposite orientation we will be able to use these conjunctions to trace out the flux tubes below the moons. These conjunctions will both validate the new anomaly source as the flux tubes and provide us new measurements, or it will refute this theory. Given the surprisingly brief minima of this new anomaly (on the order of a few minutes) it seems essential that all imaging be done via video, which provides streams of images instead of CCD which is usually spaced out over time and may miss one of these brief minima. But ANY images are accepted.

    Also a surprise during the initial JEE2012 Campaign was that despite the 3 degree tilt in Io’s orbit it still suffered extinction as it traversed the tips of its Torus. The extinction amount is less than when the Torus material is edge on, but it is still detectable. Io crosses either its eastern or western Torus Tip every single day, so endless opportunities exist to make these measurements. And as we go through edge on orbit in the following years we should see the amount of extinction peak at edge on and then diminish as the orbit of Io opens the other way. We also may have detected a pattern in the extinction that represents banding, or clumping of the material as predicted in some papers that might be there due to magnetic waves from Jupiter. These banding effects in the lightcurve are also on the order of 10 minutes from a peak to a minima, so high time resolution provided by video is valuable. Spectral data is highly desirable but will be difficult due to the very thin amount of material causing extinction. It would appear though that the Torus Tip extinction events are visible at all times every day of every year. So expect unending predictions of Io Torus Tip Jovian Extinction Events (ITTJEE).



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