Caoimhín's Content

In a few videos now, we’ve traveled to other locations to take a look at the sky. Of course, the differences can be pretty big if you travel to the other side of the equator, and if you are hunting down an eclipse or conjunction it will be clear that the view is different from other locations, you can take a look back at my previous videos on the subject if you’d like to refresh. This time we’re going to stick to the Northern Hemisphere to show how much the sky can change even with comparatively small changes in location. We’ll also look at how the Moon’s apparent position will change, even if no eclipse or conjunction occurs.

To have the best chance of noticing the difference, you need to be familiar with how the sky normally looks in your location. To make this nice and easy, we’re going to look at the sky in late February, just before the Full Moon, at 8 o’clock. This puts the very famous and recognizable Orion due South, with Sirius just below it. The bottom of Canis Major is below the horizon, and just to the East of Orion we have the Moon in Leo. For us in Ireland, the Moon will be in the Sickle of Leo, between the two stars Regulus and Algieba and a little to their West. Regulus is the brightest star in Leo and Algieba is pretty bright itself which should make this easy to see.

On the map of the world, we can see that Ireland is squarely in the Northern Hemisphere, at 51 degrees North it’s a little more than half way to the North Pole from the equator, 45 degrees North would be the halfway mark. This makes Ireland a great starting position for these kinds of comparisons, as is anywhere at about 40-50 degrees latitude. If we push through the night towards sunrise, we’ll see the Moon pass between Regulus and Algieba, ending up to their East as the Moon begins to set in the West. This means that we get to see the Moon make that journey, so if you stay up all night, or take a look at the Moon at sunset and again as the Sun rises, you’ll see that shift in position.

If we were to really travel from Ireland, straight to the East along the same latitude, we would end up looking at a different time, we would be moving back into night time, away from the sunrise. If we were to look at the sky in Central Asia at the local time of 8 o’clock, we would see a bigger gap between the Moon and the line between Regulus and Algieba. Even if we waited all night again, the Moon would almost cross the line before sunrise, but not quite. For Central Asia, the Moon would set on one side of Regulus and Agieba and rise the next night on the opposite side, you wouldn’t get to see the moment of crossing. Otherwise, the sky would look virtually the same. The stars will be practically identical, at 8 o’clock Orion would still be roughly in the South, with Sirius still visible beneath it but not quite all of Canis Major. If we push directly West, we’ll end up in Canada if we stick to 51 degrees North, we’ll end up above the 49th Parallel. This is a line of latitude, 49 degrees North, but it also divides North America into Canada and the United States for most of their international border. Despite what my computer tried to tell me in the above video, I’m still quite certain that the location I picked would be in Saskatchewan, even if the closest large settlement was Winnipeg in Manitoba.

Now that we’ve jumped far to the West, we’ve moved into daytime, so we’ll readjust the time to bring Orion back up to the South at about to 8 o’clock. Thanks to time zones, you can adjust for local time and end up seeing the same stars in the same places if you are at the same latitude. However, from here in Central Canada, the Moon has already moved across that line between Regulus and Algieba. Just like in Central Asia, the Moon has jumped from one side of Regulus and Algieba to the other between one night and the other. It’s exactly the same phenomenon that we see with eclipses and conjunctions, and indeed this could be considered a conjunction between the Moon and Regulus, but it’s not a particularly close one. This shows that you can observe the phenomenon even without a proper conjunction to help you tell, and you can see this motion of the Moon in just one night if you are in the right place and have the right landmarks to compare against.

In the video, I briefly digress into my pronunciation, as I tend to do in my videos, I often end of talking a little bit about languages. I usually pronounce the word “longitude” as if there was a “d” in it, as if it was “longditude”. This may be due to the influence of the word “latitude”. The correct pronunciation, at least in British English, is “longitude”, with the same “ng” sound as “sing”, an eng or /ŋ/ sound. This is also called a velar nasal stop. However, it appears that in at least some American English dialects, it’s more like “lon-gitude,” with the same “gi” sound as in “giraffe”. It could be that “gi” sound that I’ve accidentally turned into a “d”. This “gi” sound is the same sound at the start of “dew” and “due” in many American dialects, which are both pronounced with more of a plain “d” sound in many British dialects. This “gi” or “d in some words” noise can be written /dʒ/, it’s known as the post-alveolar voiced affricate. It is a combo of the /d/ sound, the alveolar voiced stop, and the /ʒ/ sound, like the “si” in “vision” or “ge” in “mirage”, the post-alveolar voiced fricative. That sound isn’t too common in English words, and the “d” sound is already a part of it. My in between pronunciation may be due to my living in between both those influences in Ireland, with our own Hiberno-English dialect. The special symbols and names used here are part of the International Phonetic Alphabet or IPA.

Getting back to astronomy, we’ve changed longitude on this channel before, every time we’ve chased down an eclipse or conjunction. We have also changed latitude, particularly to take a look at the Southern Hemispheres sky, you can go back to look at that video if you want to see how big the difference can be. However, even smaller changes in latitude, sticking to the same hemisphere, can have cause noticeable changes to the sky. We’ll start by moving North, and just as I kept latitude the same when changing longitude, I’ll keep our longitude the same here and only vary latitude as much as possible. Given that we’re travelling directly North of Ireland, that bring us past the coast of Iceland, into the region where the Greenland Sea and Norwegian Sea meet. Luckily, right on our longitude, 8 degrees West or -8 degrees measuring from the 0 degree prime meridian, there is an island. At 70 degrees North sits Jan Mayen Island, part of Norway, in the same political region as Svalbard Island, even if they are hundreds of kilometers apart. This little island doesn’t seem to be visible on the map I’m using in the video, so I may have missed it a little.

Just 20 degrees further North, Orion is noticeably much lower in the sky. Sirius is still visible, but practically on the horizon, with next to none of Canis Major visible. The Moon is still there, and at 8 o’clock it will be just to the West of Regulus and Agieba. Just like here in Ireland, the Moon will pass between those stars as we approach morning time. As we are on the same longitude we are in the same time zone, 8 o’clock on Jan Mayen is 8 o’clock in Cork. Some countries use time zones don’t match their longitude and local solar day, but that is a topic unto itself. If we turn ourselves around to the North, then we’ll see the North Star much higher in the sky, because we’ve moved closer to the North Pole. The further North you get, the higher it climbs, until it reaches the zenith at the North Pole itself. You can use this to at least estimate your latitude, here in Ireland the North Star is 51 degrees above the horizon, at Jan Mayen it would be 70. The closer we get to the equator the closer the North Star gets to the horizon and that’s where we are going to go next.

We’re dropping down by about 15 degrees here, which brings us to 35 degrees North, just off the Southern Coast of Portugal, roughly in line with Lagos. Now that we’re so much closer to the equator, Orion is much much higher in the sky, Sirius is there and all of Canis Major is clearly visible. This would bring the Tail of Scorpius and other features into the sky which aren’t visible from here in Ireland, but we’ll stick to the one time of night here. The Moon is nice and high in the sky, a little higher than it would appear from here in Ireland, this effect is greater when the Moon is due south. We still haven’t changed our longitude, so the Moon is still on the same side of Regulus and Algieba as we will be seeing it at this time here in Ireland. If we take a look into the North, the North Star is significantly closer to the horizon and there are times of the night when significant portions of the Plough or Big Dipper are below the horizon altogether. That trend will continue as we get closer to the equator, so we’ll take another jump down into the continent of Africa.

Much closer to the equator, but still 17 degrees above it, lands us in Mauritania, near the oasis town of Oualata or Walata. This is still a good few degrees above the equator, but now we’re so close to the equator we’re seeing constellations that aren’t visible from Ireland at this time of the year. The bright star Canopus is visible under Sirius, part of the constellation Carina, the Keel, as in the keel of a ship. From here, the Moon is still in the same place relative to Regulus and Algieba, but certainly higher in the sky and almost directly to the East. Of course, if we take a look over towards the North Star again, it’s significantly closer to the horizon, just 17 degrees above it. At the time we are viewing it, we’re already missing a good chunk of the Plough, with only the top peeking above the horizon. We’re certainly still in the same hemisphere, the North Star is above the horizon, even if it could now be blocked out in valleys or by mountains, but we are starting to see parts of what is normally considered the southern sky, the Large Magellanic Cloud isn’t far below Canopus in the sky.

We’ve travelled pretty far, to four different countries, passing over six or seven more, from islands onto the mainland and over into another continent. This can all make the journey see extra large. To contrast this, a similar degree of change can be seen from within one country if it is big enough, or long enough in cases like Chile. It has come to my attention that some of my YouTube viewers are from the United States, so it is the example that I’m Using, given that it spans a good few degrees in both latitude and longitude. Originally, I was going to go with close to the center of the Northern US, on one side of Great Lakes to put the view just across the border into the United States from Canada. However, starting further East makes the diagonal motion more dramatic. I end up at about 43 degrees North 76 degrees West, around Syracuse in Northern New York State, and then drop down to 28 degrees North and 114 West, into Baja California in Mexico. The Gulf of California is a bit South of the Mexican border with the United States a therefore the State of California, at about 32 degrees North, and Northern Maine is further North and East than Northern New York, at up to 47 degrees North and 68 degrees West. This is just with the continental United States, including Alaska and Hawaii would lead to even more drastic differences.

The differences here would be similar to the differences between Ireland and North Africa, with Orion appearing a little bit higher in the sky for the northernmost parts of the US compared to our view in Ireland, and similarly they would be higher in the southernmost areas compared to Southern Europe, but this could be to a much greater degree depending on your location, more comparable to the view from the Sahara. This of course isn’t even the biggest country, and similar degrees of variation would be seen in Russia or in Canada, but a lot that variation is would be in longitude rather than in latitude, especially for the more populated parts. The United States has quite a big variation in latitude, not as big of course as Chile or Argentina, where of course there would be less space to change longitude.

Even though these jumps around the world have certainly shown some noticeable differences, they still aren’t as extreme as the poles themselves, and we may take a look at the view from the poles as we come up to the equinox in March. If you enjoyed this article and would like to see the description for the next video (and the link to it) when it comes up, you can subscribe to this website or directly to the YouTube channel, you can also follow Caoimhín’s Content on Instagram. That way, you’ll be sure to know when something new is out and you can join me back here to read about it.