Today we are going to look at a few more of the interesting positions that Jupiter’s moons will take relative to each other in the month of October. Firstly, of course we’re going to have a quick look at Jupiter in the morning from here in Ireland, just to see where its moons are like for us. On the 14th only see two of them are visible Ganymede and Io, Callisto and Europa seem to be hidden behind Jupiter. If we go through a couple of dates Europa and Callisto do get fairly close together, but if we move through a little bit of time they move past each other, rather than in front of each other, from our perspective. That’s okay, a commenter was nice enough to list a number of locations where conjunctions and occultations will be visible.
So without further ado, we will get back to the correct date, the 14th, and we will head to the capital of Nepal, Kathmandu. From Kathmandu in Nepal we will move back towards morning time. No matter where you are, we’re going to be seeing Jupiter in the morning. Zooming in a little bit closer on Jupiter, it looks like Ganymede and Callisto are both very close together and also close to going behind Jupiter, hopefully we will see them overlap before they disappear. Through a low power telescope it definitely looks like the two moons are fusing into one. Taking a closer look, it’s more of a glancing blow, although it is pretty good, almost half of Callisto is being occulted by Ganymede. This is a partial occult occultation, a lot of Callisto is being covered up by Ganymede, but not all of it. All of this happening before 5 o’clock in the morning, so definitely this is going to occur in a good level of darkness. From Nepal, these things are still going to be fairly high in the sky. This is closer to the equator than we are in Ireland, so it is going to be a pretty good view.
That is the first of them, we are going to move to Tripoli in Libya. The locations are all capitals or capitals of areas. There are a few Tripoli’s, Tripoli in Libya was known as Tripoli of the West, rather than Tripoli of the East, which would presumably be the one in Lebanon. There is a Tripoli in Southern Europe as well, in Greece. We are in the North African country, and we will move forward towards morning time, which brings Jupiter into the sky. We need to move forward to the 15th to be on the correct date, and zooming in there are a number of Jupiter’s moons visible. It looks like Europa and Callisto are so on top of each other that it was hard to notice that there was two separate moons there at all. We’ll move through time and see what I would call a perfect occultation, even though it’s more of a transit. Europa is too small to block out all of Callisto when Europa is closer to us, but it is completely in front of it. With a high enough power telescope, if you could see the details on the moons, this would be a particularly fantastic one to see. Again, this is very early in the morning, just before sunrise. This looks perfect at just about 4:30 in the morning on the 15th, but I would recommend observing it over the course of at least about half an hour, from 4:18 all the way through to just about 4:45. That should give you enough time to see all of this occultation, but really looking its best at just about 4:32, 4:33.
We have more to see of course. I mentioned in a few of the previous videos where we were looking at Jupiter’s satellites occulting each other and having conjunctions with each other, there are so many things in the Jovian system that these conjunctions and occultations happen fairly regularly, but we do need to be in specific locations in order to see them. This next specific location, comes up as Tarawa, Micronesia in Stellarium, but the Tarawa Atoll it is the capital of Kiribati. It is part of the Gilbert Islands, The Republic of Kiribati is the name of the country. It is a country that occupies a large area, even though it is composed of many small islands it takes up a fairly big region of the Pacific just along the equator. We are very close to the equator on Tarawa and we’re zooming in on Jupiter, on the 17th to catch Europa and Ganymede very close together. Io also quite nearby, so we’ll move through some time and it looks like Ganymede and Europa are the two to come together. We’ll see how much of an occultation we get and it is another perfect one. We have Europa perfectly in front of Ganymede, and again, it’s too small. Europa is too small to completely cover up Ganymede. This happens pretty quickly, even in real time Europa slips away quite quickly. It’s finished just after 5:30, and starting at about 5:20, it lasts just about 10 minutes, less than 10 minutes for this total transit to occur. That is another fantastic one, but again, you would need an incredibly big telescope to see these details. Most telescopes will only show two moons appearing to blend into one, and of course, you would need to wait even longer for them to visibly separate when using lower power. That brings the end closer to the Sun rising, but at 5:30/5:20 in the morning, it’s still perfectly dark enough. again, we’re so close to the equator that this is nice and high in the sky. That is from is Tarawa in Kiribati.
We are traveling back onto the continent for the next one, we are going to Bishkek, the capital of Kyrgyzstan. We are looking again at the morning sky, but we need to move forward to the 21st in order to get things in the right position. Zooming in it looks like Ganymede and Io are close together, but also very close to going behind Jupiter. Zooming in a little bit closer the Great Red Spot is visible along with Amalthea. Even at this level of zoom, it’s clear that Ganymede must be blocking out a lot of Io, we have to take a closer look to see the details. It is a full occultation, an occultation proper, what most people would call an occultation. Io completely vanishes behind Ganymede, and the little moon Adrastea does as well. Adrastea also gets occulted by Ganymede, so that is an interesting one to catch, and then Adrastea passes in front of Io. So this gives an idea of how complex this system is with all of these moons moving around each other. The tiny Adrastea must be closer to us than Io while also being further from us than Ganymede, essentially sandwiched in between them. There are multiple events happening there, so this is a particularly good one, visible from Bishkek in Kyrgyzstan on the 21st of October. With a slightly lower power telescope, too low for Adrastea, too low to see the details on Io, we can absolutely see the Great Red Spot there, and Amalthea coming out from just behind Jupiter as well. These are all visible very early in the morning, just around 2:45 is when this occultation peaks. I would recommend starting to observe at around 2:40, a little before 2:45, and then we can see Io coming out the other side by just 2:50. Being early in the morning does put Jupiter lower in the sky, but it’s high enough in the sky that it’s not getting obscured by too many atmospheres.
Lastly, sticking to a similar region, we are going to the capital of Mongolia, Ulaanbaatar or Ulan Bator. We are again zooming in on Jupiter in the morning, we’re quite late in the morning at just 4:50. We’re going to move forward to the 24th, and all of the Galilean moons are lined up on one side of Jupiter. It looks to be Ganymede and Europa are the close pair again and again, it’s a perfect occultation. It’s almost more of a transit than an occultation, maybe an annular occultation could be a good word for these kinds of events. Europa is completely in front of Ganymede, but too small to block it out. We’ll come back to just before 5 o’clock, 4:58, and moving forward, Europa comes in front of Ganymede. It is completely in front of Ganymede and then it passes off to the side again, finishing there by just 5:08, less than 10 minutes for that occultation to occur in its totality. That one from Ulaanbaatar in Mongolia, again, early in the morning. Of course, no matter where you are on Earth, this is going to occur early in the morning but of course whether or not you will actually see occultations and conjunctions of those moons depends on being in a very specific area while also taking a look at Jupiter. Coming back to Ireland, I don’t believe we will see any of these, at least none of the ones that I’ve described, but we are still getting a very nice view of Jupiter’s moons at least.
I hope that you get to see the moons, Jupiter’s moons, through a telescope at some point in the near future and hopefully you get to see one of those rare events if you are in the right location. If you enjoyed reading about them here, then please do like this piece. If you like this kind of content, then please subscribe to this website and my YouTube channel. Thank you very much for reading and hopefully I’ll see you back here next time.
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