This podcast has been recorded by us here from New Zealand for Space Place at Carter Observatory and the Jodcast, for the December night sky 2018. The Jodcast is a volunteer podcast about astronomy set up by astronomers based at the University of Manchester’s Jodrell Bank but aims to cover astronomy carried out all over the Earth and beyond.
We have some instructions for you as to what to do with the December night sky.
For those of us who don’t read the instructions, we just have some amazing stuff that we wish to share and those who do neither instructions nor stories, here’s the gossip. Did you know there’s going to be a comet in the December night sky? How about a Meteor Shower? And a Full Moon? And the Summer Solstice? And did you know that this Christmas we celebrate 50 years since we went around the Moon? Oh yeah and also in December, the Americans are aiming to land a probe on an asteroid to get a sample and, – my favourite – someone calculated all the starlight that adds up in the Universe, so starting this month we will be fully informed about how many photons are reaching Earth, since the dawn of time, or so they say.
Here is what you need to do:
Look for the comet around the 16th of December. It should appear on the Eastern horizon just in between the Pleiades and the Hyades. Perhaps take a picture of it too, just because you can, it’s going to be really bright. Keep an eye on our site for instructions for how to do that if you need help.
Look for the meteor shower anytime between 7 and 17 of December (that is, yes you’re right almost in the same time as the comet.) It’s the gemenides so the radiant (the point in the sky that seems to “rain stars” is in the constellation Gemini.
Avoid the full Moon – now depends if you are into moonlight or not. I’m not, it casts too much light and I cannot see the stars properly, so I’m trying to avoid it as much as I can. The good news is that the first two weeks are good for observing, since the New Moon will be on the 7th of December. The awesome thing is that this month’s full Moon will coincide with the Apollo 8’s 50 years around the Moon celebration.
Summer solstice: Just a few days before that, at 11:23 AM on Saturday 22 December, Earth will be at its maximum tilt towards the Sun. What does it mean for us? Well, it will be the shortest night and with the Moon almost full, best thing we can do is just celebrate light. Speaking of which, our Sun went stealth, it’s in a minimum of a minimum but just because we can’t see any spots it doesn’t mean there’s nothing to learn about it. The Parker solar probe has now joined the rest of the successful missions out there and we are looking forward to some good data from it.
Since December is the month of major celebrations, we think a star party might be in order.
Well if you have never been to one, here’s a great opportunity. It could be a MoonParty if it’s around Christmas or else a star party could work around the 7th of December more or less a few days.
Now the trick is the night is extremely short – we wanted to photograph 47 Tucanae the other day and had to wait until 9:22 pm and even then there wasn’t good enough for proper imaging, only for lining up. So your efforts might be best conserved to try and find the comet, here’s a comet party, we don’t get these too often and I do remember a few years ago a comet appeared in the New Zealand Sky around this time. It was fun and it wasn’t as bright as this one, we needed telescopes then to see it. This one is a naked eye comet.
So comet-party seems like a good idea. The best time to look at it is just after sunset and on the 16th of December will have the magnitude of approximately 3. What does that mean? It means we can see it with the naked eye.
Have you ever tried to pronounce a comet’s name? 46/P Wirtanen (go pronounce that in one word!)
P stands for periodic and 46 is that it’s the 46th to be discovered (in case you were wondering the first ever was Halley’s comet) Wirtanen will arrive from the direction of Cetus / Eridani and is very tiny. Only 1,2 km in diameter, Wirtanen has a short period too, 5.4 years.
What’s cool is that this comet was the original target for ESA’s Rosetta spacecraft but the launch window was missed so they sent the probe to another comet with an even better name (just because is longer and harder to pronounce) 67P/Churyumov-Gerasimenko.
What’s a magnitude 3?
If you ever managed to spot the famous galaxy Andromeda, then you have the answer. Something that looks like Andromeda (3.4)
Now that you know where to look, and what you might find, the comet can be your centrepiece for the comet-party. But nothing says that you should not look at the stars and deep sky objects.
New Zealand is in a great spot for observing the night sky, and we, of course, get the whole Southern Sky but also a reasonable chunk of the Northern Sky as well. We can’t see the stalwarts of the Northern Sky such as the Big Dipper and there’s no taking in the beautiful face on spirals of M51, the Whirlpool Galaxy, or M101 the Pinwheel Galaxy.
At this time of the year the nights are getting shorter and shorter and the telescopes of the early evening are being swapped with BBQs and the smell of lithium grease is replaced with the smell of burnt sausages. But while some of our fellow Wellingtonians are going to bed or spinning embellished stories around the embers of their BBQ we are cracking open the Space Place Domes and collecting some ancient photons.
Some favourites of mine are visible in the night sky and the early part of the month will be ideal to try and see them given the Moon will be well hidden. The first of these is M74 and unfortunately, despite all of the aperture we have available at Space Place, we are not going to see this one visually because of it’s very low surface brightness. We’ll have to borrow the van and take the portable Meade over the hill to the very dark skies of the Wairarapa to see this beautiful face on spiral. Luckily it’s not all bad for galaxy hunting in December as not too far from M74 is the bright galaxy of M77 – also known as Cetus A. This one is easy to spot even from central Wellington. We won’t see the faint outer regions of the spiral arms but the bright active core is very visible and at 33 Million light years distant the photons from this object have spent a long time making their way to Wellington.
Despite not having M51 and M101 to look at, we do have some very impressive galaxies in the Southern Sky. One of these is NGC 253 – also known as the Sculptor Galaxy. This is large spiral galaxy at an angle to us so it looks like an elongated ellipse. It’s relatively bright and easy to spot it you’ve got plenty of aperture. You’ll have to put your light bucket on the back of your scooter and head to a dark sky location to make out much detail, but if you do, you’ll be in for a treat as you take in the complex shapes and clumps of detail visible on the disk. Sculptor is about 12 million light years away appears about 27 arc minutes long so is quite big.
Quite close to Sculptor is the tight spiral galaxy known as NGC 300. This is a great galaxy to view as it’s quite close at only 6.6 million light years – for Northern Sky observers it’s a bit like a mini M33. Viewing from Wellington will show the bright core but you’ll have to head to the hills to get any detail out of the spiral arms. Keen astrophotographers will have a better time in Wellington as this galaxy is bright enough to burn through the light pollution and produce quite a nice picture.
The problem with viewing galaxies is that they don’t really look anything like the beautiful photographs people take. They are often just a faint grey smudge in the eyepiece and you have to use your best visual observing skills to get any detail out of what you’re looking at. This is when it’s great to swing the telescope around to the majestic brilliance of the likes of the Tarantula Nebula. This gives you a picture in the eyepiece very similar to what photographers capture, just not in colour. This big giant bright complex of gas clouds and massive stars looks a bit like a spider, hence its name and it is a must see of the Southern Sky and is almost compulsory viewing on any observing evening.
If all the above fails, you could always have a Moon Party.
That could be really spectacular since exactly 50 years ago the first people orbited around the Moon, the astronauts of Apollo 8. Some amazing things happened during that flight including taking the picture that changed the world, Earth rise. One little picture is credited as the most important legacy of the Apollo programme, showing Earth half hanging in shadow and suspended in the middle of nothing at all. Humans saw their planet for the first time as a whole world, a small, blue, finite globe in the distance. It’s the image that is credited with starting the environmental movement and has been used as a hopeful symbol of global unity. So we think if you’re going to have a Moon Party this December it’s going to be pretty cool. Again keep an eye on our website www.milky-way.kiwi we will post some more content there.
There’s one more thing I want to talk about, Mars.
Mars is still visible in the sky!
Mars will always have a special place in my heart and now has a new resident, InSight.
InSight was the mission that brought the first cubesats to Mars and now sits happily on the red planet stretching its arms. Literally .
Hear here the sounds of Mars.
We wish you happy hunting for comets and galaxies this month, and if all that doesn’t work then grab yourself a couple of craters on the Moon.
Clear skies from Haritina and Sam here at Space Place at Carter Observatory in Wellington New Zealand, and see you next year!
**We are very grateful to the amazing Rhian Sheehan, the famous Wellington composer whose song, “An afternoon on the Moon” is featured in the podcast.**