Caoimhín's Content

Today’s video, we are going to be looking ahead to the end of February to the parade of planets. However, to shake it up a bit, we will be doing so from a few other latitudes. I generally show the sky as it would be seen from here in Ireland, because that is where I am, but it’s easy for me to forget that this quite northerly latitude is far from the most populous latitude. There are a lot more people living closer to the tropics than even this far north, so if the parade of planets is going to be particularly difficult for us to see here in Ireland, that certainly doesn’t mean it’s going to be difficult for the majority of people.

From 52 degrees north, we’re going to head down to 37 degrees north. This would be right down to southern Europe or northern Africa going straight down from Ireland. Broadly, this would be roughly around the Mediterranean, and it’s also going to cover a lot of the United States. A lot of the more populous cities in the United States are on a similar latitude, such as Washington D.C. and San Francisco. Parts of Ireland are further north than the northernmost part of China, the south of Ireland is about level with the very northernmost part of China, most of Chinas population is further south, with 37 degrees north being closer to larger cities like Beijing. This is still a little north of Tokyo, one of the largest cities in the world, and one of the most populated regions, in general, but much closer than 52 degrees north. Just by going down in the latitude a few degrees here, just 15 degrees, the amount of people who would be seeing the sky from this latitude is far, far greater than the amount of people who would be seeing the sky from the latitude that we’re at in the south of Ireland,

Looking west from this latitude as sunset’s just starting on the 25th of February, we’ll certainly see Mercury just a bit after 6 o’clock. Taking a closer look and leaving it get a little later, Saturn becomes visible. Saturn and Mercury should be at least briefly visible in the sky together. Mercury is definitely visible, Saturn however is a little bit tricky, it comes out so low that even bushes and small buildings can block it out. Of course, if you really want to see the parade of planets, you do need to get out to the coast, or some other location with a clear view. The Stellarium software can simulate a perfectly flat zero horizon, however this is a landscape that just covers the area below the mathematical horizon. It is sort of too perfect. Even in a real flat location, and by a real flat location, I mean an actually existing location that is flat, it still won’t be perfect. Even if the location is really flat, any real flat location is still not going to have a perfect horizon all around. Not even an ocean is perfectly still, and even with large lakes, the wind blowing over them will pick up waves along the way. Using the a unrealistically perfect clear view, we can definitely see Saturn and Mercury. Using the naked eye, if your eyes are good, we can see Saturn emerge at 6:20 and it doesn’t quite kiss the horizon there until 6:40.

So we’ve got a good 20 minutes, which of course isn’t that long, but that 20 minutes gives us a chance to see Saturn and Mercury. Mercury will come out a little earlier, and all of the other planets you’ll be able to see for quite a lot longer. Jupiter and Mars in particular will be up for most of the night, and Venus will stay visible for hours. As long as you catch Mercury and Saturn at the start, you can relax and take your time catching the other planets. This is still as it would be seen from a city, and of course one of the reasons I pushed down in latitude was to get to a more populous latitude and people generally live in cities. There are fewer people with a dark sky with no light pollution, regardless of the latitude. However, if you live down around 37 degrees north and are also lucky enough to have no light pollution, then Saturn can come out at just 6:15, and of course it’s still not going to kiss the horizon until about 6:40, a bit closer to half an hour instead of just 20 minutes. It is a small difference, but there is a limit to how much light pollution can help, if something is very close to the horizon and very faint, it’s not going to be in the sky for very long.

That extra 10 minutes or so can still make a difference, especially because the mathematically perfect horizon I’m basing the times on just isn’t quite real. The extra 10 minutes that you’re getting compared to the what would have from an area with light pollution, that will usually be the object appearing earlier, and higher if we’re seeing it in the west. The ground is going to eat in on the end side of those few minutes. Depending on the horizon, you might only have 10 minutes really if you’re from the city, you might have closer to 15 if you’re in the countryside, because you’ll be able to see Saturn that little bit higher in the sky. Especially if you are observing using your eyes, it’s good that the extra time you’re getting is when Saturn higher in the sky when it’s a little bit easier to observe. Of course, if you’re using a telescope or binoculars, you really want it to be as dark as possible for the sake of your eyes and your telescope, which means lower to the horizon. A lower latitude will mean Saturn appears higher above the sunset glow, but pointing a telescope at Saturn even there might not be the safest thing to do. If you’re careful and if you take the right precautions, it should be fine, but do keep safety in mind. Zooming in as much as possible while keeping both Mercury and Saturn in view won’t reveal that much detail, though might just about catch Titan bulging out from Saturn, but you would need a very wide angle telescope to see both Mercury and Saturn at the same time.

It’s going to be better if you’re actually at the equator, and we’re still 30 odd degrees away from the equator, we can go significantly lower without hitting the equator itself. Pushing down to just about 23 degrees north puts us into North Africa. This is just under the southernmost part of the United States of America, not far off big population centers like Miami, and through the top of Mexico. The latitude passes through the Arabian Peninsula a little south Dubai and some big population centers around there. This is also level with North India, and just the top of Southeast Asia. We’re still not at the equator but we are closer and that is going to make a big difference. We can see Saturn much, much higher in the sky at about the same time. You should see Saturn as early as 6:20 if we’re still looking at the sky here without any light pollution. I’ll fix that, I’ll make it worse by adding back in the light pollution so these things are a little bit harder to see. A little bit harder to see does make it a little bit more realistic for most people unfortunately, but hopefully that’s a problem we can solve in the future,

Looking for Saturn with a reasonable amount of light pollution, there’s a little bit of a dot there at just 6:30, but because we are closer to the equator now, it should stay above the horizon for a little bit longer. Before it quite hits the horizon, Saturn gets extincted by the atmosphere at 6:50. Even though Saturn hasn’t quite set, it is definitely still above the horizon there, it is blocked out. It has been extincted by the atmosphere combined with the light pollution because of course, they are both problems when you’re in a city. The extinction of the atmosphere is going to be a problem everywhere, but you add light pollution on top of that and things may disappear just a little bit higher off the horizon. Maybe from higher latitudes this issue would not be as obvious, given that it might not be as dark when Saturn gets this low, but definitely from here closer to the equator, the thickness of the atmosphere is apparent. The combination here means that going out into the countryside doesn’t just let you see Saturn for extra time at the start, it can help Saturn resist the extinction of the atmosphere for longer because it’s not also competing with light pollution.

Of course, the extinction of the atmosphere is more of a factor if you have a really perfect horizon, if you’re in a really flat area or at the western coast, or if you’re up very high. I may at some point try to demonstrate the difference that height can make in how much you can see. If you’re up on a mountain, it does sort of make the horizon, functionally lower for you, you should get to see a little bit more. I’ll try and check that out sometime soon.

Moving out to the countryside, Saturn and Mercury have popped up at about 6:20, and they’re staying with us until about 6:50. We’re still getting about a half an hour once when we’re in the countryside compared to the 15~20 minutes when we’re in the city. I would be expecting slightly longer from the equator, but we’re not quite at the equator yet. We will get all the way down to the equator or at least close enough. I’m not a full degree off, I’m only a few minutes off of the equator. After degrees you’ve got minutes and seconds in the system of measurement of altitude and latitude. We’re looking at the sky from about 44 minutes south.

We’re still in the countryside, so we will head back into a city. I usually bring up the light pollution just to something like Cork City, around Bortle level 5~6. I know that most large population centers suffer from a lot more light pollution than a little city like Cork. From the city, Saturn becomes visible by about 6:30 and Saturn and Mercury stay with us until just about 7 o’clock. Saturn seems to be getting extincted by the atmosphere just before 7 o’clock if you’re in city, so just about half an hour from the city if you are right on the equator. Pushing out to the countryside, Saturn’s already clearly visible as a little dot at just 6:30, and Saturn doesn’t quite get extincted by 7 o’clock, so it’s really a full half hour, maybe a little more. this is significantly better than what we’d get to see from Cork City. Saturn and Mercury are at least above this perfect zero horizon, and if we turn north, we’ve got Jupiter, Mars, and Venus as well. We need to turn a little north as we’re just across the equator into the southern hemisphere. Of course Neptune is up around Saturn and Mercury, and Uranus is up nice and high by the Pleiades, though they do require a telescope. This gives us the full seven planets, all visible, comfortably in the sky.

I don’t change the height of simulated observation this very often, so I’m not entirely sure how to change it. Height is a factor, how high you are off the ground affects your view. The higher you are off the ground, the further you can view, the lower, sort of, your horizon. It is not something I change particularly often, so I may have to have a dig around for it. Given how long it took to hop through these latitudes, it is perhaps best saved for a different time.

That is another view for the upcoming parade of planets, if you are a little bit closer to the equator. I know some of my YouTube viewers are closer to the equator, maybe some readers here are as well. The description here might approximate your chances of seeing it a little bit better because our chances of seeing it in Ireland aren’t particularly good. Next time, or maybe the time after that, we will take a look at how height can affect your view of the horizon as well. I do still have a couple of weeks before the parade of planets, so I should get a chance to show the it from a few different heights before it actually happens. Do like this article if you enjoyed it and subscribe to this website and my YouTube channel if you’d to be notified about new posts. Hopefully, I’ll see you back here next time.