See Ceres cross the Hyades star cluster

See Ceres cross the Hyades star cluster

Dwarf planet Ceres is bright enough to be seen easily with binoculars in November as it crosses the familiar star cluster of the Hyades. At the start of the month it lies close to Aldebaran (α Tauri).

ceres-aldebaran-3Nov2021-50pc-annotated
Ceres is indicated by tick marks, close to the bright star Aldebaran, in this photo taken from Walmer, Kent, on the morning of 3 November. Image credit: Paul Sutherland

(This article is an update – Pallas has travelled southwards and faded considerably.)

The first two asteroids to be discovered, Ceres and Pallas, can both be spotted with binoculars in the night sky this autumn. They should be fairly easy to locate too, since both lie near recognisable asterisms, or star patterns.

Ceres, which has been promoted to the status of Dwarf Planet, will spend the next few weeks crossing the V-shaped pattern of the Hyades star cluster as it heads for opposition in November, when it will shine at magnitude 7.

Ceres-chart-2021-anno
The track of Ceres over the coming weeks. Dates are shown in the format month-day, for 0h UT. Chart by Skymania.com

Pallas, which was discovered on 28 March, 1802, is currently close to a ring of stars in Pisces, known as the Circlet. It reaches Opposition on 11 September, when it will be around magnitude 8.5 and lie almost exactly on the Celestial Equator.

Over the coming weeks, Pallas will slowly head southwards from Pisces into Aquarius, crossing the boundary on the night of the 24/25 September.

It lies not very far in the sky from the planet Neptune, and they appear of similar brightness, though Neptune is very much larger and a lot further away.

Pallas
Pallas photographed on the morning of 6 September from Walmer, Kent, by Paul Sutherland

A telescope will bring Pallas much more clearly into view, though you will never see more than a starlike point of light as it is only around 512 km in diameter and at a distance of more than 320 million km from Earth at Opposition.

pallas-track-wide
A wide-angle view of the track of Pallas over the coming weeks. Start and end dates are in the format month-day, for 0h UT. Chart by Skymania.com

Ceres, which was discovered on New Year’s Day, 1801, is similar in brightness to Pallas in early September, at magnitude 8.7. See it a little to the south of Aldebaran, the brilliant star at one end of the V-shaped Hyades cluster. (In fact Aldebaran is unrelated to the cluster and lies between us and the Hyades.)

pallas-track-sep-oct
A detailed rack for Pallas as it moves from Pisces into Aquarius. Dates are indicated in the format month-day, for 0h UT. Chart by Skymania.com

You may find Ceres a little tricky to identify among the myriad of stars making up the Hyades cluster. However, over the next few weeks, it will become more than three times as bright as it is in early September.

That will make it much easier to spot when it reaches Opposition on 26 November, by which time it will have crossed to the northeast of the Hyades cluster.

Both Ceres and Pallas lie in the main belt of asteroids between Mars and Jupiter.

Ceres-in-Hyades-stack-annotated
Ceres photographed by Paul Sutherland on the morning of 8 September from Walmer, Kent.

Catch fleeting Mercury in the morning

Catch fleeting Mercury in the morning

If you’ve never seen Mercury, then the next few mornings offer a great opportunity – but you’ll need to be quick!

Mercury-28Oct2021_DSCF3955
Mercury photographed in the morning sky on 28 October from Walmer, Kent, by Paul Sutherland

The closest planet to the Sun can never be seen in a truly dark sky because it cannot venture far enough away from it in the sky.

We only see it with the naked eye on one of its fleeting appearances in the evening or morning twilight, soon after sunset or just before dawn.

Currently, Mercury is in the morning sky and gets high enough above the horizon to be observable before the sky becomes too bright. The ecliptic – the path along which the planets appear to travel – is tilted steeply to the horizon on autumn mornings, from northern latitudes, so Mercury gets between 5° and 10° above the horizon before being lost in the dawn glow.

You need to look roughly eastwards to see Mercury, in Virgo. You will also need a clear horizon free of low cloud, buildings and hills. A sea horizon is ideal.

Mercury reached Greatest Elongation West on 25 October, when it lay 18° from the Sun, and shone at around -0.6, which is brighter than most stars.

Since then it has been slipping slowly back towards the Sun but you will have several more days into the first week of November to catch the planet it weather conditions are favourable.

Between 6.30 and 7am BST is an optimal time to seek out Mercury before the clocks go back on 31 October. After that, look an hour or so earlier local time, of course.

A fine waning crescent Moon will lie near Mercury on the morning of 6 November.

Binoculars will help you locate Mercury due to the brightening twilight sky and its low altitude. Make sure you don’t scan the sky with them after sunrise when it will be to late to see Mercury anyway.

Mercury will reach Superior Conjunction, on the far side of the Sun, on 29 November, after which it moves back into the evening sky.

SPA supports Marlborough astronomy festival

SPA supports Marlborough astronomy festival

The SPA is delighted to be supporting Marlborough Dark Skies Fest, which runs next week, from 25–31 October.

MDSF-banner

During the weekdays there will be two exhibitions in progress – Luke Jerram’s Museum of the Moon and a display of astronomical photos by Robert Harvey.

From Friday evening and through the weekend of 30–31 October there will be a packed programme of talks from a range of speakers including Chris Lintott, practical daytime workshops with Mary McIntyre and Sally Russell and observing, weather permitting. Most events are free, but be aware that many are fully booked.

The SPA will also be represented, and we’d be keen to hear from any member going to Marlborough who could help on our stand over the weekend, 30 or 31 October.

To support the work of the festival volunteers, the SPA has produced an Autumn Skywatch leaflet which will be widely available at venues around Marlborough. You can download your own copy of this guide to the autumn skies, in PDF form, by clicking on the link.

And if you are going to Marlborough, then we look forward to seeing you!

To find out more go to www.marlborough-tc.gov.uk/darkskiesfest or www.facebook.com/marlboroughdarkskiesfest.