Keep an eye on Iris

Photo of asteroid Iris
Iris, photographed on 11 October using a telephoto lens
If you want to se an asteroid, and are fed up with non-existent meteor showers and impossibly faint comets, try looking for asteroid Iris. It’s easily found at the moment, and you can see it with binoculars.

You might not have heard of Iris, but it is actually the fourth brightest asteroid. It was the seventh ever to be discovered, after Vesta, Ceres and Pallas. Its discoverer was J R Hind, in 1847, from a private observatory in Regent’s Park, London.

This is a particularly good time to look for Iris, as at the end of October it reaches its maximum possible brightness of 6.9. That is below naked-eye visibility, but easily reachable with even small binoculars. But you have to know exactly where to look.

Fortunately it is passing through the constellation of Aries, which is currently well placed looking quite high in the sky in the south-east during the late evening as seen from the UK. While not a bright constellation, it’s easily found by anyone with a basic knowledge of the sky. Its three brightest stars make an easily recognisable group. Use the map below first to find Aries itself.  With binoculars, first identify the three main stars of Aries, then use our map to ‘star-hop’ through the patterns of fainter stars to Iris.

Although Iris is about 130 million miles away, it moves noticeably against the starry background from night to night, so if you want to pick it out you need to know its position when you are looking. Bear in mind that the tick marks on the map are for midnight at the start of each day, so if you are observing before midnight, the asteroid will be close to the next day’s mark. 

Finder chart for Aries
Use the well known star cluster of the Pleiades, in the east, to locate Aries
Positions for asteroid Iris during October 2017
Positions for Iris as it moves through Aries during October 2017
Photographing Iris
Just a few seconds’ exposure on a decent camera will show Iris, but you’ll need to support your camera on a firm tripod and make sure the lens is focused on infinity. Some cameras with auto-focus may not be able to focus as the stars are too faint, so you may need to focus first on a bright star using auto-focus and then switch off the auto-focus.

With exposures longer than a few seconds, and telephoto lens settings, the stars will start to trail after more than about four seconds’ exposure as the sky moves (or, more accurately, the Earth turns). So to keep the images as points of light, use a short exposure time and a high ISO setting.

The photograph at top was made using a 125 mm lens setting on a Canon 70D camera, with a 75-second exposure. The camera was driven to follow the stars. The image is cropped.

Spooky nebulae

 Nebula IC63. Photo by Nick Hart

Nebula IC 63 in Cassiopeia. The bright star is Gamma Cassiopeiae

The sky is full of mysteries, but we’ve picked out a few that look particularly spooky for Halloween. All the pictures were taken by Nick Hart from his observatory in light-polluted Newport, South Wales. 

IC1396 in Cepheus. Photo by Nick Hart

A ghostly apparition in Cepheus – the nebula IC 1396

Nebula NGC1977. Photo by Nick Hart

Among the stars at centre of NGC 1977 in Orion is a figure covered with a sheet to scare us

IC5070. Photo by Nick Hart

A witches’ cauldron? No, the nebula IC 5070 in Cygnus.

All photos copyright Nick Hart

The real October meteors appear

Orionid meteor

An Orionid meteor in Gemini photographed on the early morning of 22 October by Paul Sutherland from Walmer, Kent

After the scare the other week in the media about a non-existent meteor shower, now for the real October meteors – the Orionids.

These appear in good numbers between 20 and 23 October, and official rates are given as 20–25 an hour. But that’s the number that could be seen under ideal conditions, which never apply in the UK, so actual rates are likely to be somewhat lower. In practice you might see one every ten minutes or so on average, if you are a good, dark location and can see all the sky with clear conditions. And that applies in the early morning hours, so be patient!

These meteors appear to come from the direction of Orion, which rises in the east at about 10 pm BST, so any meteors you see before that time won’t be Orionids. Once the radiant (the source point) rises, numbers will increase throughout the early hours. This year, the Moon is just after new, so won’t interfere with observations, and even better, the peak occurs at a weekend. The weather is a bit unsettled in the UK, but there’s still the chance of good clear skies.

Orionid meteors are typically swift-moving, with long and persistent trains. While there is no particular direction where they will appear, it’s best to avoid looking directly at or near Orion itself, as the meteors will appear foreshortened in that direction and won’t be as easy to spot. The diagram on the right shows the position of the radiant and how it moves against the starry background during the shower appearance.

Get more information on the Orionids and how to observe them at the SPA Meteor Section site. If you want to contribute, please count the numbers of Orionid and other meteors that you see in an exact period, and send them to the Meteor Section director.

Meteors and comets

The Orionid meteors arive from dust left by Halley’s Comet. Does the appearance of these meteors mean that we might see Halley’s Comet as well? Sadly, no. What happens is that the dust from the comet has spread all along the comet’s orbit around the Solar System. Halley’s Comet is now almost as far away from Earth as it can get, beyond the orbit of Neptune. It has also spread over a wider area than the comet’s orbit itself, which is why we see these particles coming through our atmosphere even though Halley’s Comet itself can’t come very close to the Earth.

Imagine the comet to be an aerobatic plane doing loops and giving out a smoke trail. You could see the whole loop as a large trail in the sky, wherever the plane happens to be, and spreading out all the time.

Every October, Earth passes through the edge of this trail, and ploughs through the particles, which dash into our atmosphere and burn up, creating the brief flash of light we call a meteor or shooting star.

Hurricane Ophelia Turns Sun Orange-red

Hurricane Ophelia has stirred up a lot of dust from the Sahara Desert, and ash-particles from wild fires in Spain and Portugal, and lifted them high into the atmosphere. Yesterday, there were wide-spread reports of the sky turning orange from many parts of the UK. By mid-afternoon the Sun showed up distinctly orange-red even though it was not near the horizon. SPA member, Michael Fullerton captured the image below from Norfolk.

Orange Sun seen in sky

 Orange sun

Orange Sun seen from Buckinghamshire this lunchtime. Photo: Robin Scagell

People across Britain have seen the Sun turn bright orange or even red. The daylight is also a strongly orange colour. We have even heard of one person fearing that the Apocalypse was upon us!

Black Cloud coverIt is also reminiscent of the cover of astronomer Fred Hoyle’s 1957 novel The Black Cloud. In that case, the darkening of the Sun was due to an alien life-form resident within an interstellar cloud that took up residence around the Sun, causing widespread panic and destruction. 

But it’s actually due to the strong southerly winds caused by storm Ophelia. These are bringing air laden with dust from Portuguese forest fires over the whole UK. 

As soon as the wind changes direction, the Sun will return to its normal colour.

Photographing the colour

Some people have said that their photos of the strange lighting effects don’t show the colours they can see. This is because most cameras and phones now use ‘auto white balance’ which takes into account any changes in the overall colour of the light. So they take equally good pictures indoors as outdoors, even though the lighting is completely different. However, this isn’t what you want when the scene contains a predominant lighting colour, such as today.

The solution is to use a Daylight colour setting if your camera has manual settings. It’s also possible that using the flash will set the camera to its daylight colour setting even when it’s on Auto.