Well it finally happened: SCUBA’s successor, SCUBA-2 has been installed on the JCMT in Hawaii. SCUBA stands for Submillimetre Common-User Bolometer Array and the original was a ground breaking instrument that finally allowed astronomers to probe the depths of star-forming regions and distant galaxies. SCUBA-2 will more of the same and then some.

SCUBA-2 can scan the sky much faster than SCUBA and will allow researchers to measure the properties of protoplanetary disks around young stars, amongst other things. Exciting stuff. It is however very big.

Whereas SCUBA was comparable to a hefty water-heater, SCUBA-2 is more like a minivan. Mostly this is because of the cryostat that is required to keep the technology inside SCUBA-2 at a very low temperature. This technology has been developed principally in Edinburgh but also in Cardiff as well a few other places.

I saw SCUBA-2 in Edinburgh in 2006 and noted its large size at the time. When I observed at the JCMT last November (2007) I asked how on Earth they intended to get the the very expensive SCUBA-2 inside the very expensive JCMT without damaging either. The answer gave was that it would be tricky, and now thanks to a series of photos from April 2nd and 3rd I know what they meant.

The full gallery of 600 photos can be found on the Joint Astronomy Centre’s JCMT pages. There is also a fairly large animated GIF file (22MB) if you would like to see the installation in action.

This is my first poster for a conference and it is going up at the UK National Astronomy meeting in a couple of weeks. Based on my SCUBA layer for Google Sky, it will found in the Education and Outreach section during the conference.

Over the summer I created a Google Sky layer that enabled anyone to access the entire SCUBA submm catalogue of maps and objects in a dynamic fashion. Google Sky was released in August and the open file format means anyone can create data for display. This layer is now publicly available thanks to help from the Canadian Astronomy Data Centre (CADC), the Joint Astronomy Centre (JAC) and my colleagues at Cardiff University.

All you have to do is install the latest version of Google Earth and then download this KML file.

Once initialized for the first time, the file will make a download of a 9MB catalogue. This takes a minute or two and once complete you can roam the sky, viewing any regions of it covered by SCUBA in submillimetre wavelengths.

As well as the data points (which appear in green) you can also view images taken by the SCUBA camera. These will only load when you are close enough on the sky to see them, to save on time and disk space.

The best thing about this Google Sky layer is that it will enable you to place side-by-side things which you can’t see with things that you can. The image below of the Horsehead Nebula is a perfect example.

In the top, in purple you can see the optical light. This is the outline of the classic Horsehead, which is located in Orion. In orange below it, you can see the dusty, SCUBA-mapped material. It slots almost perfectly into the dark region of the Horse’s head. That’s because the reason the Horse’s head exists is that the dust obscures he light and creates the shape.

If you look carefully you’ll see the ‘lozenge’ of dust in the horse’s throat. This is a clump of cold material, with a submillimetre source at the centre (the green hexagon). This is thought to be a pre-stellar core - an object which may go on to form a star.

This ‘dust’, as it is called by astronomers has the consistency of smoke and accounts for huge amount of the material in our galaxy. Many of the shapes of the nebula you will have seen arise from dark, dusty material in between the light and your point of view.

You will possibly be familiar with dust from images such as he Pillars of Creation from the Eagle Nebula. This shown below with the SCUBA map layered on top, semi-transparently.

Included with the SCUBA Google Sky layer is a set of interesting features, which will take you to certain objects or regions of the sky, to get you started. All the green hexagons come with a popup of scientific data from the CADC catalogue.

For more screenshots, see my Flickr photo set about this project.

SCUBA was a camera on the James Clark Maxwell Telescope (JCMT) in Hawaii. It was a submillimetre continuum array receiver, with a field of view 2.3 arcmin in diameter. It had two hexagonal arrays of detectors, which mapped a fair chunk of the sky in 850 microns and 450 microns.

The device was made to study regions of the universe normally dark in optical frequencies. The things you’ll see in the SCUBA data are dusty areas of our galaxy and of more distant galaxies. These are the areas where stars are born and they are being studied all the time by researchers like myself and my colleagues.

This layer adds to a growing collection of ways to look at Google Sky. there are already layers for

• XMM-Newton [Link]
• SDSS [Link]
• IRAS [Link]

Download the SCUBA Google Sky KML file here (approx 1.0kB) This will officially launch later in the week, so if you have trouble try forcing Google Earth to refresh the KML file by right-clicking and selecting ‘Revert’ or ‘Refresh’.

If you’ve ever wondered what it is that I do (this one’s for all you family and friend types), then worry no more. Today I’m giving a talk to the incoming PhD students as part of our Postgraduate Conference. All the 2nd years give talks to all the 1st years and simultaneously bore all the 3rd years.

Fun! So my talk, as a flash animation, is shown over at this link if you’re interested.

Any questions? Send them my way.

A recent BBC News article has prompted a couple of people to mention ‘this thing called SCUBA’ to me. The article is about the new SCUBA-2 submillimetre camera that has been built at the Royal Observatory in Edinburgh (with more than a little help from Cardiff University and a couple of other places).

SCUBA-2, as the name might suggest, is the successor to SCUBA which stands for Submillimetre, Common-User Bolometer Array. What does that mean? Well basically this is a device that you connect to a telescope and then record images of the sky.

Its submillimetre because it will record information in the 850 micron and 450 micron wavelegnth regimes (i.e. 0.85 and 0.45 mm). Its common-user because a) lots of people can use it and b) it makes a nicer acronym than SBA. Its a bolometer because… well its a bolometer; and finally its an array of detectors put together to make the pixels of an image.

SCUBA-2 is hopefuly the camera which will provide me with data for my PhD thesis. I have been working with SCUBA data sine I arrived at Cardiff back in September last year. I may even publish a paper based on my work so far. However the data from SCUBA will look tiny compared to that which will come from SCUBA-2.

Two of my own images from SCUBA data. Both of these show star forming regions inside dark nebulae.

The new device is incredibly powerful by comparison to the original. The BBC News article states that it will be a thousand times for powerful, but there are many ways to measure ‘power’ in this kind of instrument. SCUBA-2 will be able to map the sky 720x faster than SCUBA. So where it used to take hours to obtain maps, it will now take minutes. SCUBA-2 has a field of view at least 13x greater than SCUBA, which means you get more in each map. SCUBA-2 is also going to be twice as good at detecting point sources, which means it is going deeper into the sky.

Left: SCUBA, which is about a metre and a half tall. Middle: Me leaning on SCUBA-2. Right: The receiver end of SCUBA-2.

SCUBA-2 is going to moved to the JCMT telescope in Hawaii in October where it will be fitted to the receiver of this 15m scope. This process takes months and afterwards the deice will have to undergo what is called commissioning, where it is essentially calibrated and readied for proper use. all in all we can expect the camera to be in full use in around a year or so if we’re lucky.

SCUBA-2 will be acting as pathfinder for the upcoming ALMA. ALMA is an array of submillimetre scopes in Chile’s Atacama desert - one of the highest and driest places on Earth. This array will use the surveys done with SCUBA-2 to go deeper than ever into space using an array of 76 telescopes which will combine to give a clarity of image 10x that of the Hubble Space Telescope.