The night sky, this week, 23-29 July 2018

It is the Winter of the Planets, or the Summer of the Planets if you’re in the Northern hemisphere and they just keep getting better and better each week. This week the highlight is the Moon, though just briefly before the sunrise on Saturday morning. If you get up early enough you might catch the beginning of a lunar eclipse, unfortunately it goes complete only briefly before disappearing below the horizon so you’ll need a fantastic horizon. Wellington has a habit of having cloud on the horizon so we might not get a great view but hopefully we’ll see the east stages a bit more clearly.


Maybe how a lunar eclipse looks from orbit above New Zealand (Credit: Me)

Because the Moon is so dominating this week, it’s a bit pointless trying to see anything faint like far off galaxies or subtle nebulae structures, but globular clusters are still good, especially the brighter ones and the open clusters can be quite enjoyable even with the Moon on maximum brightness.

Early yesterday evening we popped down to the local shop for a mid winter ice cream and greeting us in the early evening sky was the fantastic sight of a very bright Venus starting to descend towards the hill to the West. Up above it, next to the Moon was a slightly more subdued looking Jupiter with a fainter Saturn more towards the East and then a bright reddish Mars rising above Wellington harbour in the East. It was a fantastic sight to see so many planets all at the same time in the sky. Had the horizon been better in the direction of Venus we may also have caught a glimpse of Mercury. Not for us though, because of the large hill in the way. Mercury is bright and at the moment is sufficiently far from the Sun to be visible if you have a good horizon. I think you’ll probably still need to use binoculars or a telescope to pick it out of the early evening before it gets too low. It’s magnitude is 1.3 and about 24% illuminated at the start of the week, though this reduces quite quickly dropping the visual magnitude to about 1.8 by Friday.

Good news for Mars, the big dust storm is apparently subsiding slowly which means we might have a good chance of seeing at least some detail on the red planet as it approaches the closest position to the Earth which is next Wednesday morning. It’ll be worth staying up because it won’t be as close again for 17 years. The opposition and the closest position to Earth are displaced by a few days as the opposition of Mars doesn’t quite coincide with Mars’ perihelion which means for a couple of days after the actual opposition, Friday, Mars keeps getting a bit closer before both planets start separating again.

Mars on 21 July from Mars Express (Credit: ESA)

Deep sky viewing is really off the cards this week but if you want to have a look at a really awesome cluster then I recommend you check out the Jewel Box Cluster (NGC 4755). This cluster lies about 6400 light years away and visually it is quite close to the Southern Cross. In the middle of the cluster is a row of three stars known as the traffic light as they are all different colours and slightly resemble a traffic light. The cluster itself has about 100 stars, most of them are blue giants, with the exception of the prominent red star in the traffic light which is a red supergiant. If you feel like getting up early in the morning, which you will be for the lunar eclipse on Saturday morning, then you will get a better view of M45, Pleiades, which will be about 20 degrees above the horizon at the time of the lunar eclipse.

How to try and see the eclipse on Saturday morning

Ian Cooper: “The Total Lunar Eclipse, will be a most difficult thing to observe from New Zealand as not only will it be close to the horizon which increases the chance of clouds or something terrestrial getting in the way, but as the moon approaches Totality the darkening moon will become surrounded by ever brightening sky so the contrast will disappear along with the moon. Some ways to overcome that is with a good pair of astronomically suited binoculars (they often have orange or purple coatings on the front lenses to enhance faint light. Or with a suitable Digital SLR camera that has a high ISO rating, 6-12,000, so that you can brighten the moon and record it. The forecast could be good for the south coast at Wellington and the east of both Islands. Best of luck. BTW Australia will have an advantage, even along the eastern seaboard where the moon will be two hours higher so to speak. Western Australia will have the best view where it will be happening around 3.00am for them!”