Caoimhín's Content

Today, we are taking a look just a few days into the future and further ahead into the coming month of December. To start with, the Sun is nice and low in the sky here in Ireland once we get just to the first of December. The time of sunrise for the 1st is just 8:19, and the sunset will be just 4:26. Of course, the sky is already bright when we are at sunrise. The sky is already plenty bright once the Sun is actually rising as the light of the Sun will start coming over the horizon for quite a bit before the actual sunrise.

Looking at the sunrise early in December, there are times for twilight as well. Stellarium shows a twilight time of 7:40, but that is presumably just civil twilight. Even as early as 7:10, or even 7 o’clock, there is still definitely light from the Sun in the sky. At this time, Mercury is visible. Mercury is coming up to its greatest elongation on the 7th of December. Around its greatest elongation, the path of Mercury seems to curve downwards. Even though it’s at its greatest elongation on the 7th, around the 5th might be a little bit better for us to see it here in Ireland, as it will be higher off the horizon. Venus on the other hand is getting very difficult to see and won’t really be visible for the majority of this month. We will head around to sunset yet again, and the Moon will be nice and high in the sky once we’re through to the 5th. The 5th is the date of the Full Moon for December. The Moon from Ireland is at 99.8% full, that’s the fullest that we’re going to see the Moon. It stays at just around 99.8% as we move through the night, but it is also very close to us.

For us here in Ireland, a helpful commenter mentioned that just after midnight is when the Moon will be at its closest for this supermoon. At just around midnight the Moon is just 351,000 and change kilometers away from us. This supermoon is the third supermoon in a row this year, and the last one for this year. Supermoons always come in a group or cluster. When the Moon is at its closest to us, at perigee, when it’s full, it is a Supermoon. If it is at its closest to us for a given Full Moon, then it will still be pretty close to its closest to us for adjacent Full Moons, any Full Moons that are near to this Full Moon. For the Full Moon this month, it’s just 351,000 kilometers away. If we go all the way back to the previous Full Moon, it will be fairly similar. Just around the New Moon, looking at the New Moon for November, we’re seeing the moon at 412,000 and change kilometers away, so at its furthest distance from us. If we keep going all the way back to the previous Full Moon, we’re seeing it at 352,000. This is only a difference of 1,000 kilometers, which for the Moon isn’t particularly much, given that its range from one extreme to the other is closer to 50,000 kilometers. That’s our Full Moon, our supermoon, for December. We will have a supermoon in January as well, but as we just saw, December’s supermoon is a little bit more super than the last supermoon we saw, and it’s just about as close as the Moon can get at about 350,000 kilometers away.

That’s on the 5th, if we come back to the 4th then at just about midnight the Moon is very close to the Pleiades in the sky. If we take a closer look, the Pleiades are going to be a little bit tricky to see. We can definitely see their brightest members, but with the light of the very nearly Full Moon, at 98.6% full, they are going to be a little bit obscured by the proximity of the Moon. All the same, we get an occultation of the Pleiades by the Moon. Pretty much at least, the Moon definitely passes in front of the Pleiades, it’s definitely occulting some of them. However, the Moon doesn’t block every star of the cluster, and certainly not all at once. The Pleiades do occupy an area of the sky themselves, the Pleiades span more of the sky than the diameter of the Full Moon, even when it’s a supermoon. On the 4th, the Moon is still pretty much a supermoon, it’s still very close to us.

The Moon is definitely occulting parts of the Pleiades, starting at around 3 o’clock in the morning. By around 4 o’clock the Moon will be in front of the majority of the Pleiades, and then it will move off as we come up to about 5 o’clock in the morning. The sky is still going to be perfectly dark at 5 o’clock. Light pollution along with the Moon makes the Pleiades harder to spot. The atmosphere being taken away would make it much easier to see the Pleiades, as would being in the countryside. Fighting with the light of the Moon and the light of light pollution is going to make those things a little bit more difficult to see. So, we’ll head out to the countryside, and that gives us back a reasonably nice view of the Pleiades even with the Moon.

That is one of the lunar occultations that is happening this month. If we turn around to the east a little bit and move further forward into the month, we’ll see the Moon coming past Pollux and Jupiter. Then it comes up to Regulus on the 10th of December. We’re still looking at the sky for 4:30 in the morning, so this occultation is likely to happen for us here in Ireland as the Sun is rising, or at least pretty close to sunrise. This is a very good occultation from here in Ireland. Regulus is really going right behind almost the center of the Moon. If we zoom in a little bit more, there’s the nice, bright blue star Regulus, completely going behind the Moon. As we’re seeing the Moon past full, Regulus appears from behind the darker portion of the Moon, the nighttime portion of the Moon. It’s almost like Regulus is appearing out of nothing, out of what seems to be empty space. Of course, it is the Moon, the Moon is a ball, so even the parts that we cannot see are there. I do think it looks a little bit cooler when the Moon occults things with its dark limb, which happens before the Moon is full. This is because of the direction that the Moon moves through the sky, from west to east. Nonetheless, seeing Regulus appearing out the of back of the Moon is pretty impressive.

This is happening just as the Sun rises, starting at just about 7:15, just as light would be starting to come into the sky, and then finishing off at just 8:22, just after the time that sunrise would be once we’re through to the 10th of December. The Moon, of course, will continue moving down in that west to east direction, passing by Mercury later in the month. This will be quite a bit past Mercury’s greatest elongation. By the time we’re through to the 18th, with the Moon pretty close to Mercury, because its greatest elongation is the 7th and because Mercury orbits the Sun so quickly, its position is going to change pretty quickly as well. We’ll move back closer to the beginning of the night again, and there are still similar constellations to what we were seeing in September. From out in the countryside we’ll see them quite early. We’ll move forward a little bit later into the month, just coming up to the solstice, and we will come back into the city just to show a more accessible version of how the sky will appear.

Come right to just after sunset, around 5 o’clock, and we’ve got some of the brighter objects in the sky. The brighter objects that are up at this time will already be visible. We’ve still got the summer triangle, but it’s already over towards the sunset as the Sun is setting. We’ve got Saturn nice and high. Saturn is going to be coming to its highest point in the sky, directly above the south, quite early in the evening, at just 6:15. That’s going to put Saturn in pretty much the best place to observe it reasonably early in the evening, which is nice. We’ve got the pentagon of Auriga up by 6:15 in the east and the bright star Capella in it. Capella is another star that will come out just as the Sun is setting. Turning around to the north, the Plough is pretty much directly under the North Star and we have Cassiopeia, nice and high, almost at the zenith. The square of Pegasus is up in the south once we’re through to 6:15, so barely into nighttime. This is now looking at the 21st so we’re pretty much on the longest night of the year, the midwinter solstice. Of course, we normally talk about the midwinter solstice as the day, but there is a night as well.

Pushing through to 9:30, that brings Perseus right above the south. In the real sky that would make Perseus seem pretty much like it’s at the zenith, you would need to be leaning straight back to see it. We can see the Pleiades nice and high as well, and all of this is visible at just 9:30. So we’ve got the square of Pegasus along with Andromeda and Perseus, we’ve got Gemini and Orion over to the east and southeast. Of course, the Geminids, which I mentioned in the previous piece, they’re peaking back on the 13th/14th of December. They’re pretty much the best meteor shower of the year and we can see them radiating from Gemini. Do check out the previous piece where I talk more about the Geminid meteor shower specifically.

Moving all the way forward to morning time, we have the Sun coming up on midwinters morning. It’s definitely nice and bright at just 8:20 again, but we have lost a bit of day time even just since the 1st. Now we’re seeing a sunrise of 8:39 and a sunset of 4:25. It looks like we have at least lost a little bit of time off of the sunrise, if not much for the sunet. Moving back through the days, the time of sunrise gets earlier and earlier as we move back back towards September. We do want the sunrise to be as late as possible, and it gets up to 8:42, but we also want the sunset to be as early as possible, and it drops back towards 4:30. We can see the sunset of around 4:25 and a sunrise of 8:40, giving us a nice short day for the shortest day of the year, the 21st of December.

That brings us all the way through the month. A little bit after the solstice we do have one more meteor shower, the Ursids. They will be radiating from in Ursa Minor. They’re just called the Ursids but it does look like that’s up above the Big Dipper in the Little Dipper, so in Ursa Minor rather than Ursa Major. They are a pretty small meteor shower coming up really right at the end of the month, so there will be another piece talking about them and maybe revisiting the Geminids as well then.

For now, I hope that you enjoyed this look forward into the month of December. If you did enjoy this piece then please do like it, if you like this kind of content then make sure to subscribe to this website and my YouTube channel. Thank you very much for reading and hopefully I’ll see you back here next time.