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Finding Neptune in 2020

Robin Scagell Top stories
Finding Neptune in 2020

Jupiter and Saturn are dead easy to find this year – you really can’t miss them, close together down in the southern part of the sky. But finding the other giant planets, Neptune and Uranus, is much more of a challenge. This page is all about finding Neptune, which is well-placed for observing from the later summer right until the end of the year.

You may think that just because you’ve got a Go To telescope, the problem is solved, but it’s not as easy as that. Neptune is actually quite faint, and even if your Go To goes to pretty well, the chances are that you’ll be presented with several stars that might be Neptune. So our guide shows you how to find Neptune even with binoculars or a small telescope, given a good sky and dark enough conditions. In late summer you’ll have to stay up after 10 pm, but during autumn it will be higher in the sky in the early evening.

Start out by finding the Square of Pegasus, using the diagram below. Mars makes this easy to find, and although the stars are not very bright (about the same as those in the Plough) they are easy to spot.

Neptune finder map
Where to find Neptune in 2020

Next you need to find some much fainter star patterns — the Water Jar of Aquarius and the Circlet in Pisces. These are visible from average out-of-town or even outer suburbs skies with the naked eye, but if not you will need to use binoculars.

From those, you need to pinpoint the 4th magnitude star Phi Aquarii as shown on the map, below and between the Circlet and the Water Jar. Fix your binoculars on this star, then look to its left.

Neptune looks like a faint star to the left of Phi Aquarii. But there are several faint stars it could be, so use the map below to work out which one it is. Being a planet, it moves position, but not very much from night to night. The diagram shows its positions for every 10 days from the end of August, with dates shown every 20 days. As you can see, it slows down towards the end of the year.

Binocular view of Neptune 2020
Track of Neptune near Phi Aquarii during 2020

The circle surrounding Phi is 5º across, which is the same as a typical pair of 10 x 50 binoculars. If you can pinpoint Phi, hopefully you’ll be able to see much fainter stars as well, plus Neptune, which is magnitude 7.8 in August and mag 7.5 in December.

If you want further help, here’s a video recorded live under the stars

Good hunting!

How and where to see Perseid meteors

Robin Scagell Top stories , , , , ,
How and where to see Perseid meteors

Perseid meteors are still visible up to 24 August so keep watching!

Stargazers are looking forward to the annual display of meteors (shooting stars) known as the Perseids. Dozens of bright meteors could be visible every hour in mid August – if you know when and where to look.

Each year the Earth ploughs through a stream of dust from the tail of comet Swift-Tuttle. The comet itself won’t return to the vicinity of Earth until 2126, but the dust particles from it have spread over a wide band all the way around its orbit. When the Earth encounters this dust stream, the tiny particles burn up in our upper atmosphere, giving rise to what look like shooting stars, known to astronomers as meteors.

Perseid meteor radiant
How the Perseid meteors could appear in a composite made over many minutes at about 11 pm on 12 August. Base image from Stellarium.

When to look for the Perseid meteors

In 2020, the night when maximum numbers occur is Wednesday to Thursday 12–13 August. But lower numbers can be seen for a week or two on either side of that date, and this is a good time of year for seeing meteors from other streams as well.

You can see the meteors from anywhere that has a good view of the sky, but ideally you need to be away from city lights. The darker the sky, the easier it is to see them. Although many of the meteors are as bright as the brightest stars, it’s easy to miss the fainter ones if your skies are not dark.

The meteors radiate away from the constellation of Perseus, in the north-eastern part of the sky in the evening. This lies just below the well-known W-shaped star pattern of Cassiopeia. But if you want to see the more spectacular meteors, it’s best to look away from that area, so as to see the longest streaks as they dash across the sky. Experts recommend looking about 40º away from this radiant point, and about 50º up in the sky, which is about the mid-point between the ground and the overhead point. So viewing to the north-west, around the Plough, or to the south, above the bright planets Jupiter and Saturn, is a good bet.

How many will I see?

Sky guides usually quote a figure known as the Zenithal Hourly Rate, or ZHR. This is the number that an attentive observer who hasn’t fallen asleep would see in perfect skies with the radiant point directly overhead. But from the UK the radiant won’t be overhead, and our skies are rarely perfectly dark. So the number will never be as high as the predicted ZHR. This year, ZHR figures of between 80 and 150 have been quoted, but in reality you are more likely to see about half those numbers even in the early morning when the radiant is at its highest.

Although Perseus is in the sky as soon as it gets dark, about 10:30 pm BST, it is very close to the horizon, so that cuts the number down considerably. And by about 1 am, when the radiant is a bit higher, the waning Moon starts to rise and brightens the sky. Even so, observers are expecting to see plentiful numbers. Also bear in mind that meteors are completely random, so they don’t come along in a regular stream. You could go for ten minutes or more without seeing a single one, then there could be two in quick succession. The secret is to be patient and alert all the time – not always easy at 2 am!

For more information on the Perseids and how to observe meteors, visit our Meteor Section site. And if you found this page useful, do think about joining the SPA – we offer fantastic value for money and we really do believe in stargazing for everyone!