If you’re up early over the next few mornings you’ll be able to see a “close encounter of the planetary kind” before sunrise. Read more
Top stories
Did you see the fireball on 31 December?
News is coming in that a bright fireball was seen across much of the UK at about 5.35 pm on 31 December. Read more
Mira the Wonder Star approaches maximum
The star Omicron Ceti, Mira, has a special place in the hearts of variable star observers, as it was one of the first stars to be recognised as being variable. Read more
A very favourable year for the Geminids
Weather permitting, 2017 should be a great year for observing the Geminids, with peak activity due to occur durig the night of Dec 13-14 (Wed-Thurs). Geminid rates will also be quite high during the night of Dec 12-13 and also fairly good during the nights of Dec 11-12 and Dec 14-15, but do be aware that rates drop off quite steeply in the nights after maximum. Read more
Today’s ‘supermoon’ – what’s all the fuss?
You can’t have failed to notice that the papers and news websites are once again reporting that there is a “supermoon” happening today. Read more
Spectacular Leonid photos
The Leonid meteors over the weekend have produced some spectacular fireballs, though as expected rates were fairly low and there was no ‘meteor storm’. Read more
Will there be a Leonid meteor storm?
A Leonid storm in 2017? Simple answer: No. Longer answer: probably not. Read more
Keep an eye on 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.
Use the well known star cluster of the Pleiades, in the east, to locate Aries
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 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.
A ghostly apparition in Cepheus – the nebula IC 1396
Among the stars at centre of NGC 1977 in Orion is a figure covered with a sheet to scare us
A witches’ cauldron? No, the nebula IC 5070 in Cygnus.
All photos copyright Nick Hart
The real October meteors appear
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.