Discovery of pulsars

The June edition of the Jodcast is out (a few hours early). It features a long, but thoroughly interesting, interview with Jocelyn Bell-Burnell who discovered pulsars by accident during her PhD in 1967. You can listen to the interview with Prof Jocelyn Bell-Burnell (MP3: 11.9 MB) or you can download the full show complete with news, what you can see in the night sky, and a comedy intro and outro.

Posted in astro blog by Stuart on Thursday 31st May 2007 (22:54 BST) | Permalink

To the Moon and back

I've mentioned it before but this year is the 50th anniversary of the dawn of the space age; the launch of Sputnik and the completion of the 76m (250ft) diameter Lovell Telescope at Jodrell Bank Observatory in Cheshire both occurred in October 1957.

In the middle of June (15-17), Jodrell Bank will be hosting a literary festival to commemorate the first move of the Lovell Telescope under power (it was hand-cranked briefly, earlier in 1957). A literary festival isn't the normal sort of thing you would associate with an astronomical observatory, but it promises to be a good few days. During the weekend three authors will talk about their work: Alan Garner (author of Elidor) will be talking about his sense of time and place on the Friday; Saturday sees a talk by Jeanette Winterson (Oranges Are Not The Only Fruit, Tanglewreck etc); Jed Mercurio (Bodies) will be talking on the Sunday about a fictional account of a Soviet manned mission to the Moon that he is currently writing. Each day there will also be talks by astronomers describing the Universe, how the telescope moves and operates, and Jodrell Bank's involvement in the space race. On Saturday there will even be cream teas served on the lawn. Scones and tea, mmmmm.

The headline grabbing event of the weekend will be a Moon-bounce poem. The Times newspaper are now running a competition to find a poem that will be read out, transmitted by a radio amateur, reflected from the Moon and received by the Lovell Telescope. This is a really interesting idea and creates a new type of poetry. Poems will have to address the theme of Time and Place, be limited to 28 lines (28 coming from the lunar month) and will have to take into account the fact that there will be an echo with a two and a half second delay (the time for radio waves to get to the Moon and back). The judging panel is a varied bunch of poets, astronomers and others and the deadline is 10am, Friday 8th June. Get your thinking caps on.

Posted in astro blog by Stuart on Tuesday 29th May 2007 (20:20 BST) | Permalink

Caves on Mars: close-up

If you remember back to March you may remember that I mentioned the discovery, with THEMIS on Mars Odyssey, of possible open-top caves on the flanks of Arsia Mons. THEMIS had a resolution of about 18m in the images. Now (via Cumbrian Sky via Emily's Planetary Blog) a new image from the HiRISE instrument on Mars Reconnaissance Orbiter shows one of those proposed cave entrances with a full resolution of 25cm per pixel!

Possible Martian cave entrance
Possible cave entrance on the flank of Arsia Mons, Mars CREDIT: NASA / JPL / U. Arizona
The detail around the edge of the cave entrance looks like somebody has punched through a polystyrene sheet albeit over 100m across. As Emily points out, for the hole to look as black as it does, presumably the cave below is so gigantic that light that enters doesn't really come back out due to too many reflections.

I must admit that these big holes sent my mind back a few years to the time I read First Men in the Moon by H.G. Wells. In that story, the main characters find an alien race (Selenites) living below the surface of our Moon. The beings had huge shafts connecting them to the surface that were covered in lids during the lunar night but let creatures called mooncalves out during the lunar day. I'm not saying that this hole is inhabited now, but for future Martian settlers, building your base underground may be a handy way to protect against harmful cosmic rays.

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Posted in astro blog by Stuart on Friday 25th May 2007 (16:35 BST) | Permalink

The carnival is in town

I'm sure most people are aware of this by now (Phil, Ian, and Pamela all beat me to it) but the 4th weekly Carnival of Space is out over at Fraiser's Universe Today. A blog carnival is a way to bring the best writing on a particular subject together, and has been long overdue in the astronomy part of the blogosphere. Check it out.

Posted in astro blog by Stuart on Thursday 24th May 2007 (19:32 BST) | Permalink


OK, this post is only tangentially related to astronomy so feel free to stop reading now if you want to. For some time I have been worrying about ranking algorithms, mainly in the sphere of podcasting but in a wider context too. This is partly because I use some in the Astronomy Media Player and I'm worried that they aren't fair. However, as the AMP has relatively few people using it I'm aware that I may be suffering from problems with low-number statistics. So, I'll illustrate the problem with something that has more users.

For the last few months I've been monitoring the "Top Podcasts" under the Science & Nature and Natural Sciences sections in the iTunes UK store and wondering how it gets calculated. I haven't been doing this systematically (because it seems impossible to get data from iTunes without typing by hand), but I have noticed a distinct trend. Whatever gets "featured", does well in the rankings. If you've never used iTunes, you probably don't know what I'm talking about (it doesn't seem to be web-accessible), so here is a screenshot to illustrate the point.

iTunes rankings
Screenshot of iTunes UK Natural Sciences section on 19/5/2007 CREDIT: iTunes is created by Apple Computers.
The screen consists of several sections. The top section is titled "New & Notable" and this provides links to new podcasts chosen by iTunes staff (the "new" is questionable considering that the Cambridge Science Festival finished in March). The "Featured" section is presumably also chosen by Apple staff and this provides larger images and links to individual podcasts that have been around for a while. On the right are the top 25 podcasts for today. I have overlaid a red, dotted box to indicate the amount of this page displayed on a 1024x768 pixel computer screen.

It would appear that to be featured (with an image) above the fold has a very strong affect on your ranking in iTunes. Of the top 10 podcasts, only one (Brain Food) is not currently 'featured' above the fold. In fact, of the top 25 podcasts, only seven are not featured on the page at all (highlighted by red boxes). Also, one one featured podcast (Science Update) does not appear in the top 25. Of course, it could be that being in the top 25 helps to get you featured but that does not appear to be the case. Over the past week I've been watching the Jodcast's rankings and they definitely lag behind being featured (the Jodcast lept up from around 26th place two days ago to 12th after being featured). It would appear that people, understandably, generally just click on the pictures put in front of them.

So having a prominent placement on something like iTunes boosts the number of people listening to a podcast. What worries me is that because people tend to choose the 'featured' podcasts it means that the folks at Apple, who decide what gets featured, have a lot of influence over the success of podcasts. With little turnover on the featured list, it can be difficult for new podcasts to build up listeners. Obviously, Astronomy Cast managed it but many others have not. This problem isn't just limited to iTunes though, with features such as Amazon's "people who bought this also bought..." tending to become boring if there are few eclectic people in the mix.

Now back to my problem. When I first put small podcast pictures on the front-page of the Astronomy Media Player, I noticed that those near the start of the alphabet started doing much better than they had done before. I then changed the listing to be sorted by popularity, and this appears to have had a positive feedback effect; those at the top reinforce their popularity and therefore remain at the top. I don't feel too happy about this and am trying to think of a solution. Obviously, popular podcasts should generally be near the top of the list but some randomness should probably be thrown in. The randomness would add a bit of churn to keep it interesting. The only problem is finding the right level between the positive feedback and the randomness. Any comments or suggestions?

Posted in astro blog by Stuart on Saturday 19th May 2007 (15:18 BST) | Permalink

Venusian Clanger

Venus can be a very bright object in the night sky and you can even see it during daytime. It has long been suggested that it is so bright that you can see the shadow cast by it. A couple of years ago Pete Lawrence took some images on a dark night by the sea showing reflections of Venus from the water and shadows cast by various objects and even his kids! Those pictures are pretty impressive but some people thought the shadows may simply be due to the brightness of the sky. Now, via Chris Lintott, I see that Pete Lawrence has done another fantastic experiment to show that it is possible to capture a shadow cast by the planet Venus.

Pete had the great idea to document the change of the shadow over time as Venus set in the west. This is brilliant because any shadows cast by fixed objects, such as lamp-posts or neighbours lights, will always be in the same direction. However, shadows due to objects in space would move due to the rotation of the Earth. This principle is exactly how you tell the time with a sundial. Pete has taken that idea and made what you might call a Venus-dial using a Clanger as a gnomon (the gnomon is the bit that casts the shadow and can be any object you like - even a person from Lincolnshire).

He took the resulting images, each spaced by seven minutes, and has made a fantastic animation (680kB). The advantage to an animation is that the eye can easily pick out the movement of the shadow even though the shadow may be difficult to see in any one frame. Also, in this case, the rate of the movement tells us if it is astronomical in origin and with no other bright objects in that part of the sky, it must be due to Venus (you can compare the direction of the shadow too). In the animation you can also see that the shadow of the windowsill gets higher on the image as Venus sets in the west.

This was a really simple experiment but with a great result. Great job Pete.

Posted in astro blog by Stuart on Friday 18th May 2007 (21:15 BST) | Permalink

International Sidewalk Astronomy Night

Since 1976, the Sidewalk Astronomers have been helping people to look through telescopes at the wonders of the Universe for free. The group was originally started by John Dobson, of Dobsonian telescope fame, in 1968. Over the years, their events have mainly been in the US. That is until now. This Saturday, 19th May, sees the first International Sidewalk Astronomy Night.

The plan is for owners of telescopes all over the world to take them out onto the street, to parks, to cinemas, to shops etc. and share the night sky with others. Check out the events already planned (in the UK there are events in Birmingham, Colchester, Essex, Huddersfield, Liverpool and the Isle of Wight so far) and if there are none near you, consider organising your own. I know Peter is planning to be in Central Park, NYC. Is anyone doing anything in Leeds or Manchester?

The only trouble for those of us in the UK, apart from the weather, is that we don't call the path by the side of a road a sidewalk. A direct translation would be Pavement Astronomers but that doesn't have quite the same ring to it. Anyway, whatever you want to call it, it is good to share the skies with more people.

Posted in astro blog by Stuart on Friday 18th May 2007 (03:09 BST) | Permalink

Pretty podcasts

Aaron says that the future of podcasting is video (update: he isn't really saying that - see below) so I thought I would point out a rather beautiful French video podcast. It is being made every two weeks or so by the folks at and shows you what you can see in the night sky. The graphics are very slick and Stellarium is used to display the simulated sky. I think it is prettier than the English equivalent from the Jet Propulsion Laboratory although that one does provide some nice images from NASA missions and amateur astronomers. Both can be found on the Astronomy Media Player which now features over 50 different astronomy podcasts in a variety of languages.

Posted in astro blog by Stuart on Tuesday 15th May 2007 (22:25 BST) | Permalink

What about the radio?!

I've just been watching one of the recent episodes of NASAcast - Beyond the Light (MP3: 1.2 MB) - about the Chandra X-ray Oservatory (sic). Just under half way through, the presenter said "Astronomers examine the Universe through mainly four forms of light; gamma, visible, infra-red and X-ray light". What?! Does NASA think there is no radio or sub-mm astronomy? Do Arecibo, Greenbank, Effelsberg, Jodrell Bank, Parkes, WMAP and the rest not exist? Even though the video does then show (although doesn't describe) a radio image, this shows the wavelength bias of the people that made the video. I would have expected better of X-ray astronomers and I would have preferred slightly quieter, and less anxious sounding, background music too.

Posted in astro blog by Stuart on Sunday 13th May 2007 (22:45 BST) | Permalink

New Media and Astronomy

I notice that Aaron Price (Slacker Astronomy) has just published another paper in Astronomy Education Review where he reviews (appropriately enough given the journal) the use of new media in communicating astronomy.

The main section starts with a list of astronomy blogs which I think is severely lacking in those by amateur astronomers (of which there are many excellent examples). I know that Aaron has experience of amateur astronomy so I was a bit surprised by that omission. He does remark that there is a striking absence of blogs by institutions (observatories/astrophysics institutes) but I'm not totally surprised by this. After all, very few non-astronomy institutions have blogs either. It somehow doesn't seem natural for an institution to be informal and blog. Plus, they can't say what they had for breakfast or what their cat is up to.

The next section in the paper is about podcasting. Aaron states that "most astronomical podcasts lack personality and are basically Web pages and blogs read into microphones". A bit harsh perhaps, but may explain the decrease in the number of Slackerpedia Galactica episodes (a new one just out). His advice is that video is the future. This may very well be true although I still think there is a place for radio (such as while driving!).

The rest of the article covers the advantages of social networking sites such as MySpace and LiveJournal, and the use of Second Life. I must admit that although the International Spaceflight Museum is great, I have lost interest in Second Life. That may be because I don't get enough of my real one though! Anyway, an interesting read and I wonder what he would make of pointless twittering.

Posted in astro blog by Stuart on Thursday 10th May 2007 (23:14 BST) | Permalink

Where is it looking?

Have you ever wondered where professional telescopes are looking? I do, but perhaps that is just because I can see one from my window. Anyway, in an attempt to find something useful - or at least not utterly pointless - to do with twitter, I have created a small script which updates twitter with the observing targets of several of the telescopes connected with Jodrell Bank. My script isn't perfect and, for now at least, mostly tells you the rough Right Ascension and Declination of the object being observed. However, if the position matches something in a basic lookup table, it will display the object name. Currently, if my script can't work out the object, it just displays "space". I'm not happy with that solution. Suggestions are welcome.

What is quite cool (for sad people like me) is to use Twittermap to see the updates displayed on a Google Map (e.g. search for "Cambridge, UK" on Twittermap to see the current target for the Cambridge 32m telescope). Today the MERLIN telescopes, tomorrow the world! Mwahahaha. What would be even cooler is if there was a Google Universe that could be overlaid with labels for where professional telescopes are looking in 'real time'.

Posted in astro blog by Stuart on Wednesday 09th May 2007 (21:25 BST) | Permalink

Stellar outbursts

There are many stars which are known to be variable and sometimes to eject matter in outbursts. This isn't just limited to astrophysical stars. The interwebs seem awash (OK, I should really get out more) with talk about the latest comments from Sir Patrick Moore (late-time giant?).

The comments are a rant about the state of TV today which Sir Patrick puts down to the number of women producers. I certainly don't agree with this conclusion which seems to link two independent trends. You may as well associate the state of TV to the decline in numbers of pirates. Orbiting Frog (YSO?) helpfully points out that three of Sir Patrick's fivesix previous producers have been women. That does rather argue against Sir Patrick's hypothesis.

Chris Lintott (YSO?) also disagrees with almost everything Patrick said too (presumably the bit he agrees with is the decline in quality of TV). Now the Bad Astronomer (a cataclysmic variable?) has decided that, in protest, he will never go on the Sky At Night (does that mean he won't even talk to Chris?). It is widely known (perhaps only amongst British people) that Sir Patrick has views like this - I have heard Sir Patrick referred to as "more right-wing than Genghis Khan". Back in 1978 Sir Patrick even described himself as "the most right-wing Englishman alive" (ref: the Science Show the other week). As long as he keeps away from talking about politics (which he has done for the overwhelming portion of the last 50 years) people generally leave him be and just listen to his comments on astronomy and the possibility of people going to Mars. It is a shame that Phil Plait has decided that the British public will not be able to see him (Phil Plait that is) because of this.

Sir Patrick's comments have now put a downer on the 50th anniversary celebrations for the Sky At Night despite the many years featuring both men and women astronomers (to me they have always just been astronomers with no need for prefixes). Orbiting Frog puts it well when he says "he’s being pig-headed and an old fogey".

Posted in astro blog by Stuart on Wednesday 09th May 2007 (10:51 BST) | Permalink

...and there's more.

I seem to have caught Sky At Night fever. The ABC's (Australian Broadcasting Company) Science Show from last week helps to celebrate the 50th anniversary and the keep in the reference to the completion of the 76m Lovell Telescope too! This week's Science Show also features a special on the 20th anniversary of supernova SN1987a.

For more Sky At Night, check out BBC1 at 23:10 tonight.

Posted in astro blog by Stuart on Sunday 06th May 2007 (19:29 BST) | Permalink

More Sky At Night Celebrations

Another post and another mention of the Sky At Night. This time it is just a reminder that the second of the 50th anniversary programmes will be airing this Sunday night at 23:10 on BBC 1. The first of these special episodes went out on 1st April and can be watched via the BBC website thanks to the very nice tech folks at the BBC. The second programme will feature the party that was held at Patrick Moore's house a week or so ago. The great and the good of UK and Irish astronomy were in attendance as you can see in the photos courtesy of and Chris Lintott.

There is also a thirty minute long anniversary programme on at the much more reasonable time of 16:45. However, I've been told that this is in the style of a 'I Love The...' programmes and doesn't actually feature Patrick, or any of the usual Sky At Night folks. If true, that is a great shame.

In other news, Ian beat me to reporting that the French satellite - COROT - has spotted its first extra-solar planet. Well done COROT. The exoplanet encyclopedia now lists 232 candidate planets. That is up by 14 since 7th April. I make that about one new candidate every two days!

Posted in astro blog by Stuart on Friday 04th May 2007 (17:00 BST) | Permalink

Of telescopes and continents

The May episode of the Jodcast is now out in the wild. Getting everyone in the same place to record it is proving harder and harder and this month we were spread over three continents. The main interview is with Dr Carole Mundell and is about gamma-ray burst (GRB) observations with the Liverpool Telescope. The Liverpool Telescope is fully robotic and has lots of programs and scripts running to automate the rapid observations needed once a GRB alert happens. Apparently she even gets automatic emails and text messages from the telescope in the middle of the night!

We also get Tim joining us over Skype from the European Southern Observatory at La Silla, Chile. It was pretty cool to be able to talk to him whilst he was on the mountain and find out what he was up to. He has let us use some of his photos from the past few days in the May shownotes. I'm very jealous.

Finally, I chose the cover art because it related to the GRB topic and I thought it was pretty interesting. It certainly isn't your traditional pretty picture.

Posted in astro blog by Stuart on Tuesday 01st May 2007 (02:35 BST) | Permalink
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