In the night sky next week, 22 to 28 January 2018

Next week the Moon is back, not in a big way until the end of the week, but enough to annoy the non-narrow band deep sky imagers. Jupiter and Mars continue to be a bit higher in the sky each morning with Mars visually getting further and further away from Jupiter after their close encounter a couple of weeks ago. Also slowly appearing in the morning sky is Saturn and if you’re quick you might get a glimpse of Mercury. The evening planets, of Uranus and Neptune are no longer in good positions for viewing with both of them setting around the time the Sun does. So with the Moon out again this week, it’s planets, clusters and the Moon.

The Planets

If you’re keen to get up a couple of hours before dawn then you’re in for a rest with Jupiter being in a great position at just over 30 degrees above the horizon in Libra, and because its nice and bright the Moon won’t be a problem. Mars is also in a good position though a bit lower on the horizon but if you’re viewing around 5am then it should be high enough to give some good views. Saturn and Mercury will be too low on the horizon and the rising sun will ruin the chance of having a good viewing session of either of those.

Moon Appreciation

I often complain about the Moon messing up observing of deep sky objects, but sometimes it is just good to appreciate the Moon and sped sometime taking it in. At the start of the week the Moon is in a good position to examine features along the terminator. Because the Moon is so bright you can start observing it earlier in the evening during the twilight. On Tuesday, the Moon will be about one third illuminated. On the terminator there will be two very nice craters called Eudoxus and Aristoteles. In the southern hemisphere these will appear in the lower part of the Moon. Towards the top of the disk, the crater Manzinus will be visible and hopefully the crater wall will be visible too with its large shadow. Heading back down the terminator is another really lovely looking crater, which I took a photo of a few years ago (see below). This crater has a really high mountain in the centre which casts a long shadow towards the other wall if the timing is right with the position of the terminator.

Further towards the middle of the Moon’s disk is the crater Theophilus, this should present a wonderful site with central mountain peaks visible casting large shadows even though it is some way from the terminator. I managed to take an image of this crater with the mountain top visible but most of the crater floor still was in the shadow.

In the middle of the illuminated part of the Moon, towards the terminator, there are two large dark areas called Mare Tranquillitatis (Sea of Tranquility) and Mare Serenitatis (Sea of Serenity). In between them is the landing site of Apollo 17. Another really interesting crater in the same area but further down is Posidonius (pictured below). It has a number of really interesting features including craterlets, linear features and mountain peaks.

By Friday the large crater Plato is visible, the challenge always is with this one to see if you can spot the craterlets in the floor of the crater. You can soak up a lot of time browsing the surface of nearest celestial neighbour and you’ll be rewarded with a huge variety of terrain with massive mountains, imposing crater walls and vast plains. Even with binoculars there is a lot to see on the surface, with the larger craters being clearly visible. With a reasonable sized telescope you can really see some amazing details.

Deep Sky

Deep sky this week will be the home of the clusters unlike last week, where some of the faint fuzzies may have been visible. So this week we are going to focus on the globular clusters near the Southern Cross. The Southern Cross sort of points towards the constellation Musca, which has a couple of globular clusters that are quite good viewing. The first one is just left of the slightly yellow star, kind of the fourth star (Delta Musca) that makes a line from Delta Crucis, through Acrux and Beta Musca. Delta Crucis is the right hand arms of the cross and Acrux is the base. Now, just a smidgen (highly technical term for about 1/2 of a degree) to the left should be a faint fuzzy blob. Under a reasonably powered telescope that should be resolved as a globular cluster, NGC4833. It’s a bit tricky to spot because its through quite a lot of dust from the Milky Way.

Gamma Musca is the brightest star immediately above Delta Musca (the slightly yellowish one) and NGC4372 is just up and to the right of the star by 1/2 a degree. This globular cluster appears about 2/3 the siz of the Moon, though with the challenging skies that the Moon presents it will appear considerably smaller. The other globular to look at is in the Small Magellanic Cloud (SMC), not 47 Tucanae (though best to have a look if you’re in the area as it looks awesome). Up and to the right of 47 Tuc is another very nice globular cluster called NGC362. It is often over shadowed by its more famous neighbour, but this cluster is quite bright and easy to spot.

Last week we recommended to have a look at the Tarantula Nebula in the Large Magellanic Cloud if you got a chance. Well, we at were lucky enough to have a clear night so we got the telescope out and trained our view towards the LMC, which was actually visible to naked eye, in Wellington! So the Tarantula Nebula was very easy to see, in the finder scope it looked a bit like a misshapen globular cluster but through the telescope (8″ reflector with a 36mm eyepiece) it looked resplendent. So in case you missed it last week, it would be worth having another look this week, though you’ll be competing against the Moon.