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For the first time since we started this blog, all four of us were in the same room together over the weekend. Well, when I say weekend, I mean New Year. And when I say room, I mean castle (we’ve had to give the castle back now sadly!)
We thought this would be an ideal opportunity to take our first ever group photo. However, this is what we ended up with:
taken during the middle portion of Total Eclipse of the Heart, which is an astronomical reference at least.
Anyway, what we really wanted to say was Happy New Year to all our readers! Thanks for visiting during 2010; please come back during 2011. If you’re very good, Stuart might even post something!
Stuart here with my first post in an embarrassingly long time. Promise to get back to blogging more regularly but until then I just wanted to share this mysterious website:
its counting down to midday today … wonder what it could be ?
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Hello everyone and welcome to this week’s Carnival of Space. If you’ve not been to one of these before it aims to be a handy round up of all the astronomy blogging that’s been buzzing round the internet in the past week. And if this week’s news isn’t enough for you head over to the Carnival Homepage for the full archive.
First up, zombie microbes at Discovery News! The idea that life on Earth was spawned by cometary hitchhikers isn’t new, but were they dead when they arrived? On a similar theme, Weird Sciences discusses a new project which aims to find out whether life on Mars (if it exists) is related to life a lot closer to home.
Sticking with Mars, 21st Century Waves talks about astronaut Buzz Aldrin’s recent book and his ideas about martian colonization. Universe Today assesses the chances the hibernating Spirit rover might wake up (fingers crossed) or whether it truly is lost for good. On a more positive note Spirit’s twin Opportunity is still going strong even if it has no time to stop and enjoy the scenery, much to The Road To Endeavour‘s disappointment. Next Big Future has a solution that would allow future rovers to harvest gas from the Martian atmosphere to give them a rocket-propelled boost.
Moving further out, the Urban Astronomer continues an interesting series on the planets with the seventh, Uranus, whilst The Martian Chronicles recounts the troubles the Hayabusa probe encountered in successfully returning asteroid dust to Earth. Still on the space travel theme, Cheap Astronomy‘s podcast this week is on the best way to power deep space missions.
Time for some much more distant planets now. The big news this week has been HIP 13044b, though you may know it better as ‘The Planet From Another Galaxy’. Dynamics of Cats, Astronotes and Centauri Dreams all cover the story. On a similar theme, Weird Warp discusses a new way of finding other exoplanets using their dust tails.
Stars are the topic for the next couple of posts. First, Science Backstage discusses how pulsars could be used to detect Earth’s motion. Next, definitely head over to Starry Critters to see the death throes of a star as a beautiful space jellyfish. A more explosive type of stellar death is concerning Simoastronomy – do puny white dwarfs make wimpy supernovae? These explosions make heavy elements; you can find out more about this over at the interestingly-named Lounge of the Lab Lemming.
I think we’ve established there are lots of fascinating things out there but can we ever go and visit them? Weird Sciences is trying to find out, whilst Next Big Future is trying to make the journey safer.
Finally, AstroWoW has started a new project to explore the Universe, one word at a time. This week’s word (thanks to some cheeky hyphenation) is Light-year. Head over there to find out more.
A proper carnival needs a firework at the end, so here’s a massive one – the Firework Galaxy (NGC 6946) as seen by the Gemini Telescope:
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It’s time for our second guest post here at the Gutter. Today Miller Crawford from The Fourth Circle is sharing his tips for easily capturing lovely images of the night sky.
Spend a few minutes surfing NASA’s Astronomy Picture of the Day archive and the overwhelming beauty of our universe might just bowl you over. The floral fronds of the Orion Nebula; the delicate wisps of a supernova remnant; the icy blue hue of the gas-strewn Pleiades; the perfect mathematical trace of a spiral galaxy: space is dead pretty, frankly.
Sadly, our eyes aren’t sensitive enough to capture all that beauty. This is where astrophotography comes in. Long exposures let the light from faint astronomical objects build up on a sensor or photographic film, allowing a camera to capture details completely invisible to the naked eye. Cutting-edge astrophotography is more than a hobby – it is a serious, demanding science that requires a bucketload of skill, concentration and patience, not to mention a telescope with a solid and accurate motorised mount and a beefed-up computer with complicated image processing software. Looking at some of the photographs in the Astronomy Picture of the Year galleries (like the ones here, here and here) can be simultaneously awe-inspiring and daunting. Sure, you’d love to take such incredible photos yourself, but how on earth do you get started in such a daunting field?
Thankfully, astrophotography isn’t just for the gadget-heavy expert; you can take satisfying astrophotos with a more modest camera setup. All you need is some knowledge of the sky, a little patience and realistic expectations. A stunningly detailed image of the Orion Nebula will be beyond you at first, but soon you’ll be able to capture stunning vistas of our galaxy with surprising ease. So here it is, a guide to astrophotography for beginners, by a beginner.
First of all, you’ll need a digital single-lens reflex (DSLR) camera. There are many brands out there to choose from, but the most popular are Canon and Nikon. Entry-level models are fine; the more expensive models are more complicated to use, and their weight can cause stability problems. A compact digital camera is less useful; you need the ability to take arbitrarily long exposures, for example. Apparently they are excellent for lunar and planetary photography, but that’s another story. An old film SLR is another option you might choose; the growing scarcity of film is a problem, and there are other technical issues that must be addressed. I’ve tried both film and digital astrophotography, and the latter is much easier.
What about lenses? The lens that comes with the camera should do you at first – you’ll be able to take some nice wide-angle shots with the 18-55mm zoom lens that comes with a Canon DSLR, for example. A telephoto lens can be useful to play with as well – I have a 55-250mm zoom lens I use to capture the Moon and various deep sky objects.
Last of all, you’ll need a tripod – as tall and stable a model as you can afford. Astronomical objects are faint, and long exposures are needed to capture them properly. Shaky hands and astrophotography don’t mix! A good solid spot to rest your camera will do at a pinch, but you’ll be very limited as to where you can point it.
Start by taking a simple photograph of the night sky. Wait for a clear, moonless night; get away from city lights if you can. Put your camera on a tripod and aim it at your favourite constellation (Orion is a great place to start) using a wide-angle lens. Scenery or trees can add interest to composition. Set your camera’s ISO number to 400 or above and the f-number to the lowest your camera will allow. Then set your exposure to “bulb” so you can control exactly how long the camera shutter stays open for. Manual focus on infinity, then take a 30-60 second exposure. Your photo should show the colours of the stars; it will also show stars too faint to see with the naked eye and maybe even a few deep sky objects. The photo below is a 60-second exposure of Perseus using an ISO of 1600. Many faint stars are visible and the famous “Double Cluster” is lurking behind the tree to the centre-right of the image.
Alternatively, your photo might be a fuzzy mess. Don’t worry: focussing can be a tricky business in astrophotography, and that simple statement “manual focus on infinity” gets entire chapters devoted to it in astrophotography books. Using your camera’s autofocus won’t work on the sky, hence the need to use manual focus. Trouble is, stars are faint and difficult to see through the viewfinder, making precise focussing tricky. If you’ve got a DSLR that offers a “Live View” LCD screen function life gets much easier. Aim at a bright star, planet or distant light, view it onscreen using Live View’s highest magnification setting and focus until the image is sharp. If your camera doesn’t have this function, you’ll have to focus as best you can through the viewfinder. Take a short test exposure and zoom in on stars in the resulting photo. Adjust the focus if they look blurry and repeat until you’re satisfied.
Camera shake is another problem that can spoil your astrophotos. Touching the shutter button vibrates the camera, meaning light from a star briefly gets spread out across the camera sensor. The longer focal length of lens you use, the more obvious camera shake becomes. You can avoid it by using the timer mode on the camera or a remote control that triggers the shutter from a distance. I use the latter method – the £20 spent on the infrared remote was money well spent!
That’s not enough, though. A mirror inside a DSLR diverts the light coming through the lens to the viewfinder. When the shutter is released, this mirror flips up and lets the light land directly on the camera sensor. This flipping action causes internal vibrations, again smearing starlight across the sensor. Many DSLRs have a function called “mirror-lock” to help alleviate this. Switch this function on and the shutter opens a few seconds after the mirror flips up. By then the vibrations have died down, giving you a shake-free photo!
Once you’ve taken a few constellation shots and become used to manual focussing, you could try to capture some “star trails”. The Earth’s rotation causes the stars to move across the sky in circles around the celestial poles. In long exposures, stars become streaks of light instead of point sources. Set your camera’s ISO number to a slightly smaller number (200 or 400 perhaps) and set the exposure time to “bulb”. Press the shutter button once, wait 10 minutes or so and then press the shutter button again. The resulting photo will show colourful trails instead of point like stars. Nearby sources of light pollution should be obvious too! Longer exposures will give you longer trails, and if you shoot near the North celestial pole you’ll see the stars forming concentric circular arcs around an unmoving Polaris. Below you’ll see a 5-minute exposure of the Winter Triangle at ISO 100. This photo was taken near the centre of Edinburgh, and the light pollution is all too apparent!
If you want to photograph the sky without star trails you’ll have to limit your exposure time. The bigger the focal length of your lens, the less time you have before the stars start trailing. With my 18mm lens, a 60 second exposure yields stars that look pretty much like points; at 250mm even a 5 second exposure gives noticeable star trails.
Astrophotos often look a little dark and muted; how can you make them look better? Entire books are devoted to the intricacies of image processing, but adjusting the exposure levels, contrast and histograms of your photos using simple software can produce great results. There are lots of programs out there that let you do this; even the basic features offered by the likes of iPhoto really improves contrast and brings out hidden details. Most of the photos in this post have been adjusted slightly in this manner.
Capturing the Milky Way is a simple route to excellent astrophotos. Consult a star atlas and pick a constellation the Milky Way passes through. Good summer bets are Cygnus and Aquila for those in British latitudes; if you’re far enough south, Sagittarius and Scorpius house the spectacular central region of the Milky Way. In autumn aim for Perseus and Cassiopeia, and Orion and Gemini make great winter targets. Use the highest ISO setting and the shortest focal length you can and expose for 60 seconds (or even 90, 120 or 180 seconds if you don’t mind small star trails). The richness of the Milky Way should be obvious in the resulting photo; you’ll notice brighter patches and dark dust lanes cutting across the band of light. Depending on where you aimed, you might even capture star clusters, globular clusters or nebulae.
Below are a few Milky Way photos I took on holiday in Greece this year. Despite the hideous light pollution to the south, I still managed to capture the Milky Way, some open clusters, a globular cluster and some famous nebulae.
If you have a telephoto lens with a focal length of 200mm or above you might want to try photographing the moon. You can let the camera adjust the exposure automatically if you make sure it takes the reading from a spot centred on the moon rather than an average reading over the whole frame. Alternatively, exposure times for a variety of moon phases, f-numbers and ISO settings are available in Michael Covington’s book Astrophotography for the Amateur or at http://home.hiwaay.net/~krcool/Astro/moon/howtophoto/ . Here’s an example I took earlier this year – a zoomed-in portion of a shot taken with a lens set at 250mm. The exposure time was 1/250th of a second. It’s a little blurry, but craters and seas are plainly visible.
If you’re photographing the crescent moon, a longer exposure (1 – 2 seconds or so, depending on the camera settings) will capture Earthshine, the faint glow on the unlit portion of the Moon caused by light reflected from Earth. The lit crescent will be horribly overexposed, but seas and craters on the unlit side will be dimly visible, as shown in the 2-second exposure below.
You could also aim for objects like the Pleiades, the Orion Nebula or the Andromeda Galaxy. Just experiment with different ISO settings and exposure times! A 20-second exposure of the Orion Nebula at ISO 1600 shows trailed stars but captures the glowing gas very well.
So what comes next? Piggyback astrophotography is the next big step; here you put your camera on a motorised mount (often the side of a telescope!) that follows the sky’s motion, allowing you to capture long exposures with pinpoint star images. This really helps you capture faint deep-sky objects; virtually all of the stunning astrophotos out there will have used guiding. The ultimate thing to aim for is prime focus astrophotography, where you attach your camera to a telescope on a motorised mount and image at magnifications a telephoto lens can only dream of. You can immerse yourself in sophisticated image processing techniques such as unsharp masking, deconvolution and other arcanely named things. Then you can start image stacking, where you combine multiple images of the same object to increase detail, dynamic range and contrast.
All of this is another story though, and it’s one I can’t tell. I’m still a beginner, but with any luck I’ll keep getting better. If you’re eager for more information, there are loads of useful websites out there devoted to astrophotography, and Michael Covington has written two excellent books on the subject – Astrophotography for the Amateur and the more recent Digital SLR Astrophotography. Hopefully I’ve convinced you that even a rank amateur can take satisfying astrophotos and have a lot of fun doing it. Go on, have a try – the results may surprise you!
By a strange quirk of fate, two of this blog’s authors are observing different mountains. Niall is currently observing on Mauna Kea on the Big Island of Hawai`i, while Stuart is at Kitt Peak in Arizona. In between preparing, integrating and using large amounts of lipsalve they have written a bit about their experiences and have taken some pretty pictures (not data). Which one do you prefer, Stuart is a better photographer, but Niall is at a better site. It’s talent vs. beauty in a blog-off.
Stuart would also like to point out that due to a staggering oversight, he has left his DSLR at home and so has had to rely on his trusty iphone and the kindness of strangers to lend him their photos.
Niall: I’m on Mauna Kea doing a bunch of observations on the UK Infrared Telescope. Conditions are currently horrible so I’m not actually taking useful data. I’ve never observed this high up before, the low air pressure was neatly demonstrated when I dropped a can of Coke as I got out of the car and it exploded showering both me and the UKIRT car.
As I’ve not take much data as the weather is so bad, but I did manage to wander out and take a few photos of the sunset from the mountain. It’s a popular site with tourists (left) as well as astronomers and as you can see from some of the photos. They seem to gather on the ridge between UKIRT and Gemini with its odd wall-less dome. While the sunsetting behind the Subaru (named, like the car company, after the Japanese word for the Pleiades) dome looks pretty, much of the prettiness is caused by high clouds which make observing very difficult.
Stuart: I can haz spectra! is what I would say if I was a cute little lol cat but as I am a gruff hirsute scotsman I wont. I am over on Kitt peak in Tucson Arizona on my first ever observing trip! “First observing trip?” I hear you say, “but I thought you where an astronomer?” well you can check out my confessions over at the zooniverse blog. We are here taking specta, measurements of the intensity of different colours that some special galaxies are giving out. We are trying to find more examples of objects like Hanny’s voorwerp using the 2.1 meter telescope here. As I said above I left my DSL at home so I am borrowing some photos from Bill Keel and Drew Chojnowski. One of the coolest things about our scope is just how many others are around it. Kitt Peak has a staggering number of telescopes, most of which can be seen in this panorama:
Our telescope is the one smack bang in the middle of the picture. Drew managed to get a couple of really cool panoramas inside the dome as well. See if you can spot what is strange about the second one. :
The hill here seems to be infested with ladybugs who cower from the sun around the bases of most of the telescopes. I had always thought of them as quite cute but this many makes my skin crawl!
So to get that horrible image out of your head here is a stunning sunset panorama taken from the catwalk of our scope (my new favorite place in the Universe) :
So just to round things up I wanted to share a quick video tour of our control room, until next time enjoy:
Wow how time flies! It’s been almost a year since this plucky band of degenerate astrophysicists decided that the internet had gone too far without their particular flavour of drivel and decided to start a blog.
Happy birthday weareallinthegutter! And congratulations on making it one entire circuit around the sun. This has been a particularly mobile year for us authors with Niall moving from Nijmegen to sunny Hawaii and Stuart moving from rainy Edinburgh to rainy Oxford. It’s been a fun year for us and an education in the way of the blogsphere. What have we learned? Well, firstly that people are really interested in things both hot and cold, with a puzzling amount of our traffic coming from posts about volcanoes and comets! All we need is nature to provide us with a comet/volcano collision and we may become more popular than lolcats!
It’s interesting to see what drives people to our site. WordPress helpfully tells us what people google to find us… and it can make for interesting reading. We’re still unsure how we could be one of the results for “Aircraft in the trojan war” but hopefully we weren’t too much of a disappointment. “Volcano from space with evil face” was intriguing enough for us to google it ourselves; try an image search for it yourselves – it’s actually pretty scary!
One thing we don’t feel like we have been very good at is getting to know you guys. So if you have enjoyed the blog, are an occasional visitor, or even if you have hated it so much that you have declared yourself our offical arch nemesis (we don’t mind – everybody needs one), why not leave us a comment to let us know (roughly) who you are?
Well, here’s to a fun year which will hopefully be the first of many. Happy birthday weareallinthegutter
The Lunar Reconnaissance Orbiter (LRO) is NASA’s attempt to create a high resolution version of Google Moon, taking high resolution maps of the lunar surface. We’ve blogged before about some of the amazing images that it’s been sending back. Its snaps to date have included the Apollo landers, lost moon buggies and it has even started legal debates about ownership of the lunar surface.
However, while the images sent back so far have been spectacular, one of the non-imaging instruments on the LRO, the Lunar Interior Seismometer (LIS), may end up stealing the show. The LRO-LIS is a prototype moonquake monitoring device which is getting its test run on this project. It uses radio waves to measure the distance to the lunar surface so accurately that extremely tiny vibrations can be detected. This means that unlike in space, where we all know that no-one can hear you scream, the LIS can essentially “hear” sounds on the lunar surface.
Seismographs were amongst the science equipment left on the moon by the Apollo missions, but these were only sensitive to strong quakes (caused by large meteor impacts), due to the technology limitations of the time. Carrying out these measurements from space is a lot more accurate anyway as the instruments don’t become contaminated by the lunar dust, and a much wider area of the moon can be studied.
Now, we don’t generally deal with speculation on this blog (except when we launched a whole Dark Matter Week on the back of a rumour of direct dark matter detection), but it looks like the LIS may be performing way beyond its specifications: rumours being whispered over coffee in academic departments up and down the country say that it’s returning some very strange results indeed. Apparently there is a very clear, intermittent, whistling noise being picked up by the device. These “sounds” seem to be emanating from craters in the Faril Loop region of the moon and are baffling the scientists on the project.
One of the researchers said that he was completely taken aback by the data and thinks it might be the most significant discovery on the moon since we have started looking at it. However the actual interpretation of the results is still ongoing. “We don’t want to drop a clanger here as some of the hypotheses about these observations are a bit woolly,” said Professor Yaffle of Postgate University, “however with a bit of luck they should knit together to form a consistent theory about what we’re hearing from the moon.”
*Note this is raw data and it has not yet been flat fielded or bias subtracted. Due to wordpress’ policy of not allowing free users to host sound files we’ve had to host this on our own Google site.