Caoimhín's Content

In almost every video I post to this channel, excepting special videos looking at the Sun and such, I give some comparison between the light polluted sky I see from the city I live in and the superior view a dark sky, with no light pollution can provide. Here in Ireland next week is Dark Skies Week, which include various Dark Sky Festivals celebrating the pristine skies we have. This video will be about the improvements you can see when light pollution is removed, and a little about where you can see such a sky. It just so happens that the darkest skies in Ireland, which include some of the darkest in the world, are very close to, or even in, Gaeltachts, those parts of Ireland where Irish is still spoken, making this just about the most perfect video to combine my love of astronomy with my love of the Irish language.

We will begin, as we often do, by looking at the sky I would see from Cork City, with a noticeable amount of light pollution, but still very far from the worst conditions larger cities can create. As the Sun sets in late March into early April, it will be practically night time by about 8:30. The darkening sky reveals Jupiter, now rather low towards the West, but still the brightest thing in the evening sky besides the Moon. Bright stars, like Sirius and Aldebaran, are easy to see as well, but it is only the brighter stars. If you were to look at the whole visible section of the sky, only about 250 stars would be visible to the naked eye. It is very tricky to count the stars in the actual sky, given that they will be continuously setting into the West while new ones rise in the East to replace them. If you were to take a photograph, perhaps using a fish eye lens, then you would have much more time to do the counting. In a sky like the one shown here, roughly 250 is what you would be able to see.

This is only the level of light pollution that we have in Cork City, and Cork City itself is only the second biggest city on the island on Ireland. It certainly isn’t a huge city, compared to many other cities around the world, like New York or London. Even in these less than terrible conditions, only the rough shape of some prominent constellations, such as Leo and Orion, are visible, with many details missing, such as the upper part of Leo’s Sickle. We can see the Belt of Orion in the middle of the Hunter, but the Sword of Orion is very hard to see. Much of Canis Major is invisible, other than the the brightest star Sirius. Those two stars there in Gemini, the Heads of the Twins, Pollux and Castor, those are bright enough to be seen, but much of the bodies of the Twins are at least quite faint. In some cases whole constellations, such as Cancer, are invisible due to the lack of stars. Normally in these videos, I go straight from a city like Cork to a perfect dark sky, but of course there is a spectrum between those ends, and most areas of the countryside will be some degree less than perfect, while still being a big improvement over the sky in the city. In this video, we go to one of the intermediary levels, similar to the sky visible from many smaller towns and villages, areas outside the larger Irish cities such as Galway, Limerick, Cork and Dublin. These locations may be comparatively in the countryside, but are themselves built up area with some amount of streetlights and houses.

If there aren’t any clouds in the sky, in an intermediary sky like this Orion’s Sword is easy to see, we can really see the Seven Sisters or the Pleiades. As well as the body of Leo the Sickle is clear at the start of the constellation. You can see the sort of bottom of Canis Major under Sirius, the bodies of the Twins in Gemini, there’s loads to see when the sky cleaner like this. I say clean, because light pollution is pollution, there is no need for it, it is purely a waste, a by product of more useful light production. If we are trying to light up the cities, that light is going to be used on the ground. There’s no need to send that light up into the sky and cover the stars. Light pollution is light created by and for people, and there aren’t any of us up with the stars. Bar 6 or so astronauts on the International Space Station, but they have their own lights so we don’t need to worry.

Looking at the less light polluted sky at 8:30, you can still see a little sunlight glow from sunset, and that can be hard to notice in a city with more light pollution. If the sky is lit up, the glow of the Sun will blend in once it is faint enough, but it will continue to stand out for longer if the sky is truly dark. The bright Jupiter almost seems bright, and it stand out along with the brightest stars. Stars like Sirius, Betelgeuse and Procyon are very clear. Even objects that are close to invisible in Cork City stand out clearly in this view, such as Orion’s Sword beginning to look like more than just a star. The Seven Sisters are almost inn a clearing of their own and remain clear as a group. For some constellations, there are already so many bright stars that finding the exact ones you need can start to get tricky, with Leo being an example if you aren’t used to it. Looking up at the asterism of the Big Dipper or the Plough, the primary stars of that shape are all bright and visible, and a few of the stars that are members of the actual constellation, Ursa Major or the Great Bear can be clearly seen as well, something that’s very hard to do if there is too much light pollution,

Moving towards morning time, this is the level of darkness where the Milky Way begins to become visible. At this time of the year, early in the morning is the best time to see the brighter parts of the Milky Way. At the end of March, around 4 o’clock in the morning, the center of our galaxy, the core of the Milky Way will begin to come into view above the South-Eastern horizon. The Summer Triangle will also be coming up with an arm of the Milky Way stretching through it across the sky. The Summer Triangle will be coming up earlier and earlier in the morning, until it begins to stay visible all night long as we cone into summer time. This year, we will need to wait until a little further into April to get the best view, as the Moon will be close to full at the end of March. There is light coming from the Moon as well, reflected sunlight, and it can be quite bright, especially when the Moon is close to full. Even if there isn’t any light coming into your sky from a city, if the Moon is full there will still be a lot of light in the sky, and it will be a little harder to see faint objects like the Milky Way. Waiting for the Moon to be new or close to new will give you an even better view of the sky. If you are putting in the effort to travel somewhere with less light pollution so you can see the Milky Way, it is worth taking the phases of the Moon into account as well.

If you want to see the Milky Way here in Ireland, usually heading into the Gaeltacht will help. A Gaeltacht is a region in Ireland where Irish is still spoken by a large portion of the population, where the language is typically used in the community as the primary language of interaction and often where there is a continuous tradition of speaking Irish as a first language. Gaeltachts are often defined by different criteria for different purposes, so a single definition is tough to find. However, although their exact borders can be tough to pin down, there are a few around the island of Ireland, and most of them are outside big cities. Some of them are in some of the darkest skies in the world. Although there is a Gaeltacht in both County Meath and County Waterford, both close to or on the comparatively bright East coast of the island, they are still both darker than most nearby larger settlements. The Gaeltacht in Galway does extend rather close to Galway city itself, one of the bigger cities in Ireland, but it is smaller than Cork city and the Gaeltacht stretches out into significantly darker areas. The Gaeltacht inland in County Cork is a fair distance from Cork City itself, limiting the influence of the cities light pollution, and much of the Gaeltacht in County Donegal is similarly removed from the larger towns. Cape Clear Island, off the southern coast, has wonderfully dark skies, thanks in part to its position on the ocean.

The two other Gaeltachts, the Gaeltachts in County Kerry and County Mayo are the ones I will prioritize here. County Kerry really has two Gaeltachts, slightly separated on two peninsulas sticking out into the Atlantic. This, combined with mountains, has given these areas phenomenally dark skies. While the Gaeltacht around Dingle, the more northern peninsula of the two, does create some light pollution, the one on the more Southern Iveragh Peninsula, is in a Dark Sky Reserve. The Kerry International Dark Sky Reserve is recognized by DarkSky International, formerly the International Dark Sky Association, as a large area of land with very dark skies, centering around a core of especially pristine skies, free of light pollution. This reserve overlaps much of the South Kerry Gaeltacht, making it one of the best places to go stargazing in the world, and being big enough to hold whole villages and towns with amenities and accommodation. The Gaeltacht in County Mayo is really a couple of distinct areas, close together on the Northern Atlantic Coast of the county. This area happens to border the Mayo Dark Sky Park and Wild Nephin National Park, an area that is protected for both its peatland habitat and recognized for it’s incredibly dark skies, being a Gold Tier Dark Sky Park. As an Irish National Park, it is publicly accessible land, it even has a visitor center. While the Park and the Gaeltacht don’t technically overlap, they are right on top of each other, with some of the closest towns to the park being in the Gaeltacht.

I can not say that these are the darkest places in Ireland. The Connemara Gaeltacht region in Galway also has amazingly dark skies, but is not currently internationally recognized, and no doubt many other areas in Ireland are similarly dark. However, I can say that these two Gaeltachts in particular, in County Kerry and County Mayo or either in or near some of the darkest, least light polluted skies, in the world, and the other Gaeltachts in Ireland offer similarly amazing views of the night sky. They offer the chance to experience the Irish language as a living language while also viewing the sky as it was seen by all of our ancestors not many generations ago. Brushing up on your Irish isn’t necessary for getting a place to stay in these places, but it certainly doesn’t hurt. This channel may primarily be about the night sky and astronomy, but here especially it overlaps with the topic of the Irish language, thanks to the Dark Skies that the areas preserving it provide.

I may put a big emphasis on picking up Irish and how great it is, but I mostly intend that message for monolingual English speakers in Ireland. If you already preserve a heritage language at home, or the language of your families home country, then also having to learn enough English to get by in Ireland is already asking enough. Of course, if you do feel like learning a third language or more, Ireland is a great place to learn Irish. Videos like these serve to show, in part at least, that Irish and any language can talk about topics like astronomy. English may be the main language of international communication, and an important language in science for international collaboration, but it does not own science of any kind. Any language can be used to discuss stars and planets and galaxies, they are no less modern and capable. Sometimes borrowed terms will get used, but English is as guilty of that as any language.

Dark Skies, and the unnecessary waste that is light pollution, are a particularly important part of astronomy to me, focusing as I do on observational astronomy. The Irish language of course is just as important to me, if not more so. The upcoming Dark Sky Week, and the convenient position of Irelands Gaeltachts in darker regions, some recognized as among the darkest in the world, served as a fantastic excuse to combine a discussion about both. I will be continuing to make an Irish Language video just once a month, until we come back around to March next year and the next Seachtain na Gaeilge. If you would like to be kept up to date with what’s in the sky, especially if you are coming to a Dark Sky in Ireland, then you can subscribe to both this website and the Caoimhín’s Content YouTube Channel, there’s even an Instagram page of the same name. If you do, you’ll be among the first to see the upcoming video about the solar eclipse on April 8th, and the English language version of this video, which will look at very bright, polluted skies as well. Hopefully, I’ll see you back here then.