NGC 1032. A perfectly edge on view of a giant spiral galaxy in the constellation Cetus, around 100 million light years away.
A lovely edge on view of galaxy NGC 1032.
This beautiful image, ablaze with the light from over 100 billions suns, perfectly captures the thin aspect of large galactic discs. Most spiral galaxies are incredibly slender relative to their diameter. The thickness of our own Milky Way is only 1% of its total 100 thousand light year diameter. So next time you see the band of the Milky Way overhead you can roughly approximate its width to be 1000 light years.
The dynamics of gravity and centrifugal force can explain much about the formation of spiral galaxies but the fine detail and the rotational speed of the various bands of stellar material are still shrouded in some mystery. Without concepts like ‘dark matter’, for instance, the outer portions of many galaxies are rotating so fast they would simply rip themselves apart.
Many people are uncomfortable with terms like ‘dark matter’ and ‘dark energy’ because they’re ‘inferred’ phenomena rather than being directly detected. This might be so but science is riddle with such pre-emptive constructions.
Take air for example. For untold millennia people knew about the existence of this invisible substance which would fill people’s lungs and impede the flow of water ‘an air lock’. However, it would have to wait until the discovery of modern chemistry for air to be properly defined as a mixture of several atomic elements (mainly oxygen and nitrogen).
I had a fun two days of astronomy guiding at the newly launched Scapa yoga festival near Loch Fyne. A perk for the job was obtaining a family ticket for the festival so I decided to take the camper van and family along too.
The drive from Inverness was pretty arduous, but when we arrived it was a lovely setting and ended up being one of the most peaceful and chilled out festivals we’ve been to. Numbers were kept at reasonable levels so that toilets and open spaces were jostle free and relaxing.
The astronomy work ran for two days late in the evening and was in partnership with the Wild Things! group. The original plan was for a late night constellation walk to the beach but as the clouds rolled in we instead elected for an atmospheric campfire, with a general discussion about the stars.
This format worked out very well with lots of interested folk dropping in to participate in what became a very vibrant Q & A, covering topics as far reaching as star navigation, astrology, shooting stars, black holes and stellar evolution. On the Saturday evening some people stayed for the whole two hours, transfixed by the discussions. Astronomy is a subject with the power to transport people back into a state of childhood wonder! It’s undoubtably the most accessible and mind-blowing of all the sciences.
By all accounts the festival was a great success and I wish the organisers lots of luck with Scapa 2019.
We were blessed with a lovely sunny day on Saturday for our day of Solar learning up at Abriachan. We were fully prepared for indoor activities as forecasts were looking pretty grey. But as the weekend swung around skies cleared and we ended up seeing plenty of Sun all day.
A day of fun solar learning
Since conditions were so good we moved everything outside, including the talk I’d prepared which was originally put together on powerpoint. I demonstrated basic shadow time keeping and direction finding, and how solar eclipses take place using a scale model of the Moon and Earth (with the moon’s orbit inclined at 5 degrees).
Based on our model the Earth and Moon were around 3 meters apart with the former about the size of a large orange. At this scale the Sun would be 10 meters in diameter and over a mile away! At this scale the relative rarity of total solar eclipses becomes clear (on average one every 18 months).
During the talk we also touched upon:
- Sun gods and how our ancestors perceived the Sun as a perfect orb with no imperfections
- The human fear of eclipses
- The discovery of Sun spots and how they revealed that the Sun is spinning
- How spectroscopy showed that our Sun was in fact a star (in very close proximity)
- Why the Sun is loosing mass – over 4 billion tons of hydrogen per second
- The ultimate fate of our Sun – how it will eventually and briefly flare up as a red giant star before cooling and shrinking down to a white dwarf
After the talk Clelland took over for some fun outdoor activities including a scale walk of the solar system, DIY spectroscopes and solar lasers using big magnifiers. We also did a fun experiment simulating the colour of the sky and sunsets using milk in water bottles.
In terms of solar viewing, I setup the 200mm with a full objective white light filter, and we also had a Sunspotter, kindly on load from Glasgow Science centre. Both setups produced clear views of the Sun’s photosphere, but unfortunately there were no sunspots to see. This isn’t entirely surprising given we’re currently bang in the middle of the 11 year solar cycle minimum, although large ones can appear suddenly at any time. We hope to one day invest in a good quality hydrogen alpha filter for these events, as these reveal many more interesting features, like edge prominences and coronal loops.
Overall a fun day of learning with great interaction and questions from the adults and little ones alike.
As the constellation Virgo rises earlier and earlier after darkness we’re entering a time of great opportunity for observing distant galaxies.
Within the upper right hand stretches of Virgo are giant clusters of galaxies strung out in loose bundles. Some of these very distant galaxies can even be see in bioculars if you’re under excellent dark skies. Telescopes will pick them out better and it’s here that aperture rules. Faint galaxies need big objective lenses to see clearly.
More galaxies are scattered to the lower right of the constellation too, including the famous Sombrero galaxy (pictured).
The Sombrero Galaxy
Your fleeting glances will look nothing like Hubble’s post processed images but you will be witnessing the hazy light from billions of ancient stars for yourself. These galaxies are island universes just like our Milky Way, and contain many billions of stars.
I’ll be giving a public lecture at the Inverness Science Festival on May 11th 2018. I’d love to use some images from local astro photographers, particularly night sky photos taken in the Highlands or north of Scotland. If you’d like your images used I’ll fully credit you in the talk. Please PM me for details.
Talk Title: Wild Astronomy
Description: The Highlands of Scotland have some of the darkest skies in Europe but how often do we escape our back gardens and ‘get out there’ to appreciate the night sky?
In this talk astronomer Stephen Mackintosh discusses what makes our Highland skies so special, the sights and objects we should look for, and how a backpack and a pair of binoculars is all you really need to open up the wonders of the night sky.
Time and Location: May 11th, 7-8pm at University of the Highlands and Islands STEM Hub, An Lòchran, Inverness Campus, Inverness
In 1054AD Chinese astronomers recorded a bright new star suddenly appear in the constellation Taurus the bull. It brilliantly out shone all other stars and was visible in broad daylight. After a year or so its light faded and it vanished.
The event was a supernova explosion – the dramatic explosion of a massive star. Today we can see the remnants left behind from this violent event – the Crab Nebula. An expanding shockwave of recycled stellar material. The above amazing image is from the Hubble space telescope.
You can see the Crab Nebula in a modestly sized amateur telescope, and as always the darker the skies the more detail you’ll see. With a 150mm scope or larger you should be able to trace out the overall mottled shape of the nebula. Use averted vision and see if you can pick out extra detail and structure.
Finding the Crab is relatively straightforward as it sits just beside the lowest horn of the constellation Taurus the bull, which sits above and right of Orion during evening skies at the moment.
Starry Skies over Loch Ness by Claire Rehr
Here’s a small piece I wrote for the South Loch Ness tourist website on stargazing in the Highlands.
South Loch Ness Tourist Site – Night Sky
“For me stargazing is about reconnecting people with the night sky, not just the raw science which is fascinating enough, but also the star lore, mythology and human connections with it. That’s something we’ve undoubtedly lost in recent times not only in terms of light pollution but also our tendency to inhabit virtual spaces within our phones and gadgets. As a people we seem to be increasingly looking down rather than up!
‘In the Highlands we’re still fortunate to have access to some of the darkest skies in Europe, and it’s something I hope we’ll do our best to preserve for future generations. Visitors from populated areas of England and the central belt of Scotland are always blown away by what they can when they get into the wilds under a moonless sky. Under the right conditions you can see over 5000 stars out here, compared to just a few hundred from urban areas. ”
“For visitors to the South Loch Ness area I recommend just heading out to some high vantage points, killing your lights and letting your eyes dark adapt. You’ll be amazed when you look up. You can also head up to Abriachan where there’s good access and parking for larger groups of stargazers”. “When the moon is new you can see breathtaking views of the Milky Way galaxy soaring overhead – a humbling reminder that we’re just a tiny part of a giant spiral galaxy surrounded by billions of other stellar companions.”
“Because of our northerly latitude (57 degrees north) we also have the privilege of witnessing many circumpolar constellations – stars that are always above the horizon. This lets us become more familiar with specific groupings like the two bears Ursa Major and Ursa Minor and rich constellations like Perseus, Draco, Auriga and Cassiopeia. During the winter months the shorter days up here also lend themselves to extended opportunities for observing. It’s a rewarding pastime that makes the cold and long winter nights much more inviting.’