Two Comets

Over at Astroblog, Ian Musgrave writes about Comet LONEOS which is currently brightening and is getting close to being visible with the naked eye. According to the finder charts it is currently between the constellations of Bootes and Virgo. Chris Lintott points out a second comet - Comet Holmes - which brightened almost over-night from magnitude 17 to 4. That means that it may also be visible by eye from a dark site. Comet Holmes (insert your own Sherlock Holmes jokes here) is currently sat near the constellation of Perseus.

If you see either of these by eye you can tick off one of my 10 astronomy things to do before you die.

Posted in astro blog by Stuart on Wednesday 24th Oct 2007 (20:10 BST) | Permalink


This is an urgent post for people in the UK and Europe. About an hour ago (56 minutes apparently) the Shuttle mission STS-120 launched without any apparent problems. The trajectory takes the Shuttle over the Atlantic and roughly over the southwest of England at about 18:30 BST. From Manchester it will only reach about 15 degrees elevation in the SSW but I'll be trying to spot it.

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Posted in astro blog by Stuart on Tuesday 23rd Oct 2007 (17:38 BST) | Permalink

Catch a Star 2008

Each year the European Southern Observatory have a competition - Catch a Star - open to school students from all around the world. As I've said before, the aim is to encourage children to work together, learn about astronomy and to research things for themselves. Catch a Star actually consists of three competitions. The first is for teams of up to three students to research a particular topic in astronomy. This has the best prizes in my opinion with the winning group visiting the Paranal Observatory in Chile - home of the fantastic Very Large Telescope (VLT). Last year's winners made a short video of their trip and put it on YouTube. The second competition is aimed at larger groups and prizes of DVD-ROMs, t-shirts and posters are awarded by lottery. The third competition is for the best astronomy-themed artwork in different age groups. Previous years have seen some great entries and the winners are chosen with the help of a public vote. This year there will also be a special prize awarded by an astronomical artist.

The deadline for entries is 29th February 2008 (leap year day!) so head over to the ESO site to find out how to enter and what you need to do before it is too late.

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Posted in astro blog by Stuart on Tuesday 23rd Oct 2007 (09:34 BST) | Permalink

Leo, there is no spoon

NASA have a tendency to make rather cheesy group shots of the Shuttle expedition crews that make me think of TV news crew publicity shots although with the suits replaced by astronaut gear. They usually have the team looking serious, or skywards, or both.

Via Avventure Planetarie, I've just seen a spoof movie poster (54 MB!) that was made for the crew of Expedition 16. The poster is in the style of... well nobody can be told what the style is, you have to experience it for yourself. You see, we know why you are there Leo, we know what you've been doing. I just hope you don't disappoint me Mr Clay Anderson.

Expedition 16
Exp 16 Themed Poster. Spaceflight Awareness have a huge version. CREDIT: SFA, NASA

Posted in astro blog by Stuart on Friday 19th Oct 2007 (12:28 BST) | Permalink

10 astronomy things to do before you die

I was over at Chris Lintott's blog and saw his link to the New Scientist blog's list of Top 10 spacey things to do before you die. There are some interesting things on there but I thought I would make myself my own list and include some obvious omissions. My list covers a whole range of phenomena or acheivements, some easy, some hard. If you disagree with my list, add your own suggestions in the comments.

10. Observe Saturn through a telescope

Saturn seen through a 14 inch telescope CREDIT: Stanimir Metchev at the University of California, Los Angeles
OK, I thought I would start with something relatively simple; observe Saturn through a good amateur telescope. Most amateur astronomers have probably already done this and for many this is what first got them hooked on astronomy in the first place. There is something magical about the very first time you see Saturn and its rings through an 8 or 10 inch diameter telescope. Perhaps the excitement is in the realisation that the photons of light have travelled a billion miles or so from Saturn to get to the back of your eye. Perhaps it is just to see those stunning rings for yourself even if the view may not be as detailed as an image from Hubble or Cassini. Either way, seeing Saturn for the first time is special. If, like me, you don't have a 10 inch telescope, go along to a star party or your local astronomical society and someone might let you have a look through one.

9. Visit Stonehenge

Stonehenge, Wiltshire, UK CREDIT: Frédéric Vincent
One of the most famous astronomical observatories of ancient times is sat in the middle of Salisbury plain in the south of England - Stonehenge. Stonehenge was built around 2200 BC. It has been argued that Stonehenge's purpose was to observe the setting midwinter Sun which would mark the return of longer days. So, I suggest a visit on the winter solstice.

8. Stand astride the Prime Meridian

Prime Meridian
The Prime Meridian at Greenwich. CREDIT: Dr Perry Tompkins, Physics 100 class
Although Greenwich Mean Time was established in the 1700s, it wasn't until 1847 that the first time zone was created. By international agreement, the Prime Meridian - the point taken as zero for longitude - was chosen to go through the Royal Observatory, Greenwich, England. The Observatory has a great visitor centre (and spangly new planetarium) and has the Airy Transit Circle which was originally the zero of longitude - the Prime Meridian. If this trip is too easy, try a harder version; stand astride the Prime Meridian and the Equator (0 longitude, 0 latitude). That's much harder as it is several hundred miles south of Ghana in the Atlantic Ocean. You will probably need a boat for that one!

7. Visit Meteor Crater

Meteor Crater
Meteor Crater CREDIT: David Roddy, United States Geological Survey
This one is on the New Scientist list and I include it because it is probably the most famous impact crater on Earth. The Barringer Meteor Crater was created about 49,000 years ago when a 30-50 metre wide asteroid hit northern Arizona. A visit to the site will show just how easily life on our planet is threatened unless we get our act together and seriously think up workable plans to deflect asteroids.

6. See a naked-eye comet

Comet McNaught
Comet McNaught CREDIT: Ian Musgrave, Astroblog
Comets are leftover parts of the solar system that reside out beyond the orbit of Pluto in the Oort cloud. They can be described as snowy dirtballs and some of them occasionally pass through the inner solar system. When they do, the warmth of the Sun causes them to heat up and the frozen water and other gases sublimates off into space leaving a dust tail behind them as they go. As they near the Sun they also interact with the solar wind and this causes an ion tail which points away from the Sun. Seeing a great comet is more down to luck than planning as new, spectacular comets can appear with relatively little notice. The most spectacular comet of the past couple of years was Comet McNaught which was visible in the Southern Hemisphere. I remember Hale-Bopp and Hyutake from a few years ago and just about remember seeing Comet Halley from the kitchen window back in 1986.

5. See a rocket launch

Space Shuttle
Space Shuttle launch
There is something inspiring about seeing something launched into space and these days you have a few choices of where to go to see it happen live. The most popular choice for most is Cape Canaveral in Florida but those in other parts of the world should check out the European Space Agency's Spaceport at Kourou, French Guiana, the Russian Baikonur Cosmodrome, India's Satish Dhawan Space Centre north of Chennai or Japan's Tanegashima Space Center.

4. See a green flash

Green flash
Green flash CREDIT: Pekka Parvianinen
A green flash is a phemonena caused by the refraction of light in the Earth's atmosphere which makes the top edge of the Sun momentarily turn green. This can last for a fraction of a second up to a few seconds as the Sun sets. There are several different types and they are very difficult to see because the conditions have to be right - a west facing coastline is a good place to try. If you've already seen a green flash try to spot a violet flash!

3. Be at one of the Earth's poles at night

South pole
View of stars and aurora at the South Pole Observatory. CREDIT: NOAA
I'm not fussy, either one will do but the South Pole may be easier as it is on dry (very) land and there is shelter for warmth. The poles are very special places because they mark the axis about which the Earth turns. The spinning causes the stars to appear to sweep out huge circles in the sky. At the pole, the pole star (Polaris in the northern hemisphere and Sigma Octantis in the south) would be directly overhead and all the other stars would be circling it every 23 hours 56 minutes. That also means that stars near the celestial equator would be near the horizon and would travel horizonally. From a geeky point-of-view, you would be at the only places where an equatorial mount behaved the same as an alt/az mount. For best views, I suggest being there at night although that does mean you'll probably have to winter over!

2. Have an asteroid or comet named after you

Asteroid Itokawa CREDIT: JAXA
How cool would it be to have a five mile wide lump of rock millions of miles away from the Earth named after you? To acheive this is going to require some work though. One way is to hunt for comets as they are usually given a name corresponding to the person or people that discovered it. Finding comets and asteroids isn't just limited to the professionals as many comets are found by amateurs. Alternatively, if you aren't the best observer, you can hope that you meet the Committee on Small Body Nomenclature's guidelines and sit back and hope they'll pick you.

1. See a total solar eclipse

Solar eclipse
Total solar eclipse CREDIT: Williams College Eclipse Expedition 2001
Every so often, the Moon passes directly between the Earth and Sun. The result is total solar eclipse. Total solar eclipses happen every year or so but they are only visible from a narrow strip of the planet each time so are not easy to see. It is the most thrilling type of eclipse and many become eclipse chasers to repeat the experience of seeing one. So, if you haven't already seen one (or have but want to see another) the next solar eclipses are August 1st 2008 (Canada, northern Greenland, the Arctic, central Russia, Mongolia, and China), July 22nd 2009 (India, Nepal, Bhutan, Bangladesh, China, Japan) and July 11th 2010 (Cook Islands, French Polynesia, Easter Island and South America). There is nothing like being in the shadow of the Moon and seeing stars during day time. The closest I got to this was Cornwall back in 1999. Even though I only saw a sky full of cloud it was still magical.

Other things that didn't quite make my list because I ran out of space were: seeing aurora, observing Pluto, using a large professional telescope (not remotely), completing a Messier Marathon, spotting a micro-meteorite impact on the Moon, seeing a meteor shower, watching the dance of Jupiter's moons, and observing a transit of Venus.

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Posted in astro blog by Stuart on Friday 19th Oct 2007 (00:20 BST) | Permalink

Telescopes in XML part 3

I think I may have caused some confusion over my idea for a simple telescope XML file. The plan is not to recreate the excellent efforts of the global Virtual Observatory community. They have been working for several years to developing XML exchange formats in order to control telescopes remotely, allow networks of telescopes to talk to each other, respond to events and mine astronomical databases. These, necessarily, require lots of thought, consideration and attention to the details. For instance, in a research setting it can be vital to know that the FK5 and ICRS give positions different by 0.01 arcseconds. However, my idea was simply to answer the popular question that visitors to an observatory ask - "what is it looking at?" - and do it in a common format for many telescopes.

The aim of this is to serve the interested member of the public rather than the professional astronomical community. It does not have to be perfect or try to provide all information that might possibly be wanted. However, it should be easy for those with some scripting ability, but little knowledge of the astronomical details (e.g. wavelengths, bandwidths, instruments, exposure times, and coordinate transforms), to make stuff by bringing together different feeds. That is my plan. Perhaps it is more trivial than people were giving me credit for!

Following the outline in my last post, I was left some suggestions by Mike Peel and links from real VO people. I've talked to Mike about his ideas and I like the inclusion of a field-of-view. I can imagine this being used to scale a cross-hair (or other symbol) in something like Google Sky or Stellarium and that would convey something about the instrument in a fairly unobtrusive way. In terms of the object type, Andy Lawrence pointed me towards some VO documents. I don't think the IVOA definition is appropriate, but there is a proposed list of unified content descriptors (UCD) which looks promising.

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Posted in astro blog by Stuart on Monday 15th Oct 2007 (18:59 BST) | Permalink

Telescopes in XML part 2

Several weeks ago I mentioned my motivation for a simple telescope XML file and then I came up with a suggested format. Other things got in the way so I haven't really done a lot on this since. However, now seems a suitable time to push this forwards.

I've altered things slightly, taking into account some of the previous suggestions. Below is a table of tags with allowable values. Dave P suggested changing the <coordinates> tag in order to split the latitude and longitude up and provide future proofing for telescope not on the Earth. However, I would prefer to stick with the simple format that Google Earth uses rather than something all-singing and all-dancing like they use for the Virtual Observatory.

e.g. <name>42ft</name>
descStringA short description of the telescope. Limited number of characters?
e.g. <desc>The 42ft telescope at Jodrell Bank Observatory</desc>
linkURLLink to a web page with more information about the telescope.
e.g. <link>http://www.blah/42ft.html</link>
imageURLAn image showing the telescope. In jpg, gif or png formats.
e.g. <image>http://www.blah/42.png</image>
PointThe latitude/longitude of the telescope. Should be provided where possible, although for some it makes little sense e.g. Hubble.
Point -> coordinatesCoordinatesSame format as used by Google Earth i.e. latitude,longitude. Longitude ranges from 0 to 360 degrees. Latitude ranges from -90 to +90 degrees. A sign should be provided for latitude to avoid confusion. Optional but strongly recommended.
e.g. <coordinates>53.235864,-2.306592</coordinates>
heightReal numberThis is the height above mean sea level in metres. For space-based telescopes this may be omitted. Optional but strongly recommended.
e.g. <height>213.1</height>
statusStringThis is an open format field to provide any status information.
e.g. <status>Cryogenic failure, motors stopped.</status>
time*ISO 8601 Date StringTime when the information is this file was valid.
e.g. <time>2007-10-14T12:00:00Z</time>
objectStringThis contains the name of the object. An optional type attribute should be taken from the astronomy journal keyword list. Multiple types can be included using";" or "--" as a separator so that it is consistent with journal papers.
e.g. <object type="pulsars: individual: PSR J0534+2200">The Crab Pulsar</object>
position A tag to hold the current coordinates of the observation. The amount of precision in the coordinates is left to the author of the file. This allows for 'fuzzy' positions to be given when required.
position -> raReal numberThis is the Right Ascension as a single number in decimal degrees. RA in hours, minutes and seconds can be easily calculated.
e.g. <ra>123.456</ra>
position -> decReal numberThis is the Declination as a single number. Dec in degrees, arcminutes and arcseconds can be easily calculated.
e.g. <dec>+45.678</dec>
position -> epochStringA standard epoch for the Ra/Dec coordinates such as: B1950, J2000 etc
e.g. <epoch>J2000</epoch>
position -> azReal numbersThis is the azimuthal position in decimal degrees (north = 0, east = 90). An optional attribute dem can give the demanded azimuth if it is different to the actual azimuth of the telescope e.g. <az dem="172.34">170.06</az>
position -> elReal numbersThis is the elevation of the telescope in decimal degrees (horizon = 0.0, zenith = 90.0). An optional attribute dem can give the demanded elevation if it is different to the actual elevation of the telescope.
e.g. <el dem="34.6">34.567</el>

* these are required tags

Finally, does anyone have any experience writing DTDs or XML Schema?

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Posted in astro blog by Stuart on Sunday 14th Oct 2007 (13:06 BST) | Permalink

A tilted perspective

The Bad Astronomer (and Dave P) both mention a website that claims that the Earth has changed its tilt. This claim is wrong and anybody can easily prove this for themselves.

Most nine year olds in the UK could probably tell you that the Earth spins and the axis of that spin is tilted by about 23.5 degrees. They should also know that that tilt causes the seasons. This is correct and you can check it for yourself by playing around with a torch (the Sun) and something round like an apple or orange (the Earth) or go look it up in pretty much any basic astronomy book. The rotation of the Earth causes the Sun, planets and stars to appear to rise in the east and set in the west. Check this yourself by going outside on a clear evening at sunset.

The website claims that the tilt has increased by another 26 degrees. Let's assume that this had happened (let's not worry about the sheer impracticality of this happening for now) and try to work out how we could test this hypothesis. Well, there are two ways a tilt could be applied and the website is unclear on which they mean. Firstly, the whole Earth could tilt by 26 degrees. If that was the case, the north star - the star that is over the north pole - would no longer be above the north pole. It would now be 26 degrees away from it. That is quite a long way and would be very noticeable in star trail photographs. Try this for yourself; go outside on the next clear night, locate the north star and then just watch it for a couple of hours. I checked it on Friday and Saturday night at it was in the same place as normal for where I live.

OK, perhaps the website isn't referring to the whole Earth tilting. Perhaps the surface of the Earth has just "slipped" relative to the rotation axis of the planet. If that was the case, what would the effect be? Well, that would mean that pretty much every point on Earth was at quite a different latitude to what we would expect. That would then mean huge changes in daylight, sunset and sunrise times for all of us. As the Bad Astronomer rightly points out, parts of Europe would be above the arctic circle and so should be experiencing very little daylight at all as it is winter. However, the sun seems to be rising and setting at times I would expect for this time of year so that rules out that kind of tilt.

Both these possibilities have observable predictions. These predictions do not require multi-million dollar equipment to test though; you can go outside with a bit of paper, a pen and a watch and disprove them within a few hours. Given how easy it is to show these predictions do not match with the real world, I can only assume that the website is some kind of spoof. Unfortunately, not everyone is as clever as a nine year old (nine year olds are pretty smart I'll have you know) so I suspect that this will be spread as "true" amongst adults who are not smart enough to think for themselves.

Posted in astro blog by Stuart on Thursday 11th Oct 2007 (14:52 BST) | Permalink

New Horizons and Jupiter

On January 19th 2006, the spacecraft New Horizons was launched on its long journey to dwarf planet Pluto. New Horizons will be the first spacecraft to visit a dwarf planet although it won't be hanging around when it finally gets there in July 2015; it will be passing by at a zippy 14 kilometres per second (Mission Guide, page 4). Back at the end of February, New Horizons zoomed past Jupiter. In doing so it received a gravity assist which boosted the speed of New Horizons by about 9000 mph. That helps it get to Pluto more quickly but also gave an opportunity to test the instruments by making some observations of Jupiter.

Those results have been discussed at the Division for Planetary Sciences (DPS) meeting in Orlando this week. It was brought to my attention via Pierre Nel on Twitter and I subsequently visited Emily Lakdawalla's blog for more details. Emily gives an excellent overview of all the results announced so far which include super-fast wave features in Jupiter's atmosphere, lightning stikes near the poles, a lack of small moons and changes on Io since Galileo (and even during the encounter). Interesting stuff and well worth a read. I can hardly wait for the Pluto encounter.

Posted in astro blog by Stuart on Wednesday 10th Oct 2007 (22:39 BST) | Permalink

Twitter Account Hacked

I have been using the social networking site Twitter for some time and have slowly been building up a presence there. I don't 'tweet' very much but yesterday I mentioned about the 50th anniversary of the launch of Sputnik and that I had been listening to BBC Radio 4's Dirk Gently. After that, I was unable to connect to the Twitter website. At the time I assumed it was one of the increasingly frequent outages and went off home to bed. However, it seems that somebody else had taken control of my account and was posting very dodgy comments under my name. I didn't even understand what one of the comments meant, but I assume that it was supposed to be rude.

The result of this is that some nasty person has had their fun pretending to be me and trying to destroy my reputation. Luckily, a couple of people who have been following my blog or twitter feed for some time spotted the change of personality. So, many thanks to Dave P and Andrew

who both contacted my via email or this blog to inform me that they thought my twitter

account had been hacked.

This is my first experience of personal identity theft online and it isn't nice. To have someone pretend to be me is unsettling and unpleasant especially when they start posting highly inappropriate comments. Apologies to everyone who thought those comments were from me. They most certainly weren't.

At the moment I am unclear as to how this person hacked into my account. Did they guess my password? Have I got a key logger on my computer? Did they intercept my network traffic? Did somebody hack into my computer in another way? What I do know is that my computer was off and in my laptop bag from about half eight (BST) last night. I have considered deleting my Twitter account but I worry that the perpetrator of last night's activity may then make a new account in my name. Does anyone have any suggestions of what to do?

Posted in astro blog by Stuart on Friday 05th Oct 2007 (09:10 BST) | Permalink

Sputnik at 50

It has been widely mentioned in the blogosphere already (Ian, Tom, Phil, and Andrew) but today is the 50th anniversary of the launch of Sputnik. Sputnik was launched by the Soviet Union and was the very first artificial Earth satellite. The satellite itself broadcast for all with a radio set to hear. However, the UK also got itself involved in the event back in 1957. The Lovell Telescope at Jodrell Bank was still being completed when Sputnik was launched but it was quickly rushed into action as it was the only radio telescope in the world at that time that was capable of detecting the booster rocket with radar. We talked to Sir Bernard Lovell about those early years on the September and October Jodcasts (part 1, part 2 and part 3 audio) so have a listen.

We've had a fantastic day at Jodrell Bank with the Russian Ambassador, the UK Science and Innovation Minister and the Astronomer Royal (Martin Rees) all here to celebrate Sputnik, the Lovell Telescope and the announcement that the headquarters of the Square Kilometre Array (big future international radio telescope) will be based in Manchester. A busy day with lots of important people from the world of radio astronomy to talk to. Look out for some interviews from today on the next Jodcast.

Nice to see that Google made a special logo for today too.

Posted in astro blog by Stuart on Thursday 04th Oct 2007 (18:32 BST) | Permalink

Great Scott!

The October issue of the Jodcast is now out (it's October already!) and features an interview with Professor Albert Zijlstra about his area of research - planetary nebulae. Appropriately, given the upcoming anniversary of the launch of Sputnik, there is also the third and final part of the Audience with Sir Bernard Lovell covering the period from October 1957. Oh and given the excuse of travelling back to the 1950s, there is a time travelling intro/outro. Now, I must go sort out my flux capacitor.

Posted in astro blog by Stuart on Monday 01st Oct 2007 (11:09 BST) | Permalink
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