See asteroid Pallas in the evening sky

Updated 7 September with photoPallas, one of the brightest asteroids, and the second asteroid to be discovered, comes to opposition in September. Here’s how to find it for yourself.

An annotated, stacked image of Pallas, near the Circlet asterism in Pisces, taken on 6 September, 2021, from Walmer, UK, with a FujiFilm X-T10 and Samyang 85mm lens. Image credit: Paul Sutherland

While too faint to be seen with the eyes alone, the minor planet will be easy to spot if you have binoculars and know just where to look.

A telescope will bring it much more clearly into view, though you will never see more than a starlike point of light as it is only around 512 km (318 miles) in diameter and at a distance of more than 320 million km (200 million miles) from Earth at opposition.

During September and October, Pallas lies near some fairly easy to find asterisms, or patterns of stars within the constellations of Pisces and Aquarius.

A wide-angle view showing how Pallas tracks across the sky during September and October, 2021. Image credit: Skymania using Cartes du Ciel

As September opens, Pallas can be found shining at magnitude 8.7 in the constellation of Pisces. It reaches opposition on the 11th, when it will shine brighter at magnitude 8.5.

By coincidence, Pallas will lie almost exactly on the Celestial Equator on the night of opposition, making it just as easy target a from the northern or southern hemispheres.

After opposition, Pallas slowly fades again as it continues southwards, crossing into Aquarius on the night of the 24/25 September. At the end of September, it will have dimmed to magnitude 8.8, and by the end of October it is at magnitude 9.4.

Pallas’s track across the sky during September and October, 2021. Positions are marked for 0h UT every two nights, using the format Month-Day. Image credit: Skymania using Cartes du Ciel

Pallas was discovered on 28 March, 1802, by a German physician, Heinrich Olbers, who devoted his nights to observing the heavens. He went on to discover another asteroid, Vesta, in 1804.

It was the second asteroid to be found, following the discovery of Ceres, on New Year’s Day, 1801, and so is also known as (2) Pallas. It lies in the main belt of asteroids between Mars and Jupiter. Today, many thousands of asteroids are known. They are thought to be leftover debris from the formation of the Solar System.

Ceres is itself easy to find in the night sky in late 2021 as it crosses an easily recognisable star cluster, the Hyades, in Taurus. We have a guide to seeing Ceres for yourself.

Asteroid Pallas imaged with the SPHERE instrument on the VLT telescope in Chile. Image credit: ESO/M. Marsset et al./MISTRAL algorithm (ONERA/CNRS)

Pallas has never been visited by a spacecraft. However, a high-resolution imager called SPHERE, on Europe’s Very Large Telescope (VLT) at Paranal, Chile, was able to discern dimple-like craters on its surface, making the asteroid resemble a golf ball!

The asteroid is stony in nature with a composition thought to resemble that in carbonaceous chondrite meteorites.

How to photograph asteroid Pallas

If you have a camera with a shutter that you can leave open for more than a few seconds, you can try to take a photo of Pallas. You will need to keep the camera steady, preferably by mounting it on a tripod, and pointed towards the stars on the Pisces-Aquarius border.

Ideally, you should put the camera into manual mode, if you can. Choose a high ISO, or speed setting, such as 1600, and make sure the stars are in focus by zooming in on a bright star in the field. Brilliant Jupiter is not far away, so can be used to check the focus before you aim the camera to put Pallas in the field of view.

You can find more tips on photographing asteroids in our previous guide to spotting Vesta.

Related: Asteroids – leftover debris from the Solar System

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts