Practically a year since the kilt wearing: Thoughts on the subject.

Yes, I can’t believe that it’s practically a year since I started wearing the kilt for a month. (It’ll actually be a year on Monday.)

So, have I worn it at all since? Yes, once, to a fancy dress party. Strangely, it didn’t feel as unusual as I thought it might. Obviously my body has a memory of this being normal.

I still can’t see myself wearing a kilt casually without prompting, especially during the Summer. Having said that, it probably wouldn’t take much in the way of prompting to get me to do so. If I were to do so I’d probably get a lighter weight kilt and one in a more interesting colour than black.

As for wearing one more generally, such as to work, well I’d need a bit more convincing. I do, now and again, get a comment from one or two people saying that they’d like to see it again. However, I don’t want to make those who felt uncomfortable with it last year to feel uncomfortable again.

Actually, dear reader, I would be interested in your thoughts on the whole kilt wearing episode, now that time has gone on, if you have any.

Flash, bang, what a picture.

On Friday afternoon an old friend posted on my Facebook wall a link to an article about a new supernova discovered on Thursday in one of the arms of the Whirlpool galaxy (M51) and wondered if I’d seen it.

Fortuitously, Friday evening was practically the clearest sky I’ve seen in Oxford so after Saturn became eclipsed by the house roof (which now happens annoyingly early) I decided to have a go at imaging it.

After I having to re-aligned the telescope, as the LX90 mount doesn’t seem to take care of accumulated pointing errors very well and was hence pointing in the wrong part of the sky, I managed to get on target. I swapped the eye-piece for the camera, found a nearby bright star to get focus and then moved back onto the subject.

I tried a couple of exposures, all taken using an infra-red remote control so as not to cause the ‘scope to bounce around, but only one of these was usable. The trouble is that the LX90’s mount isn’t that good at tracking the sky either, even with an equatorial wedge. It seems to jerk forward randomly every minute or so making exposures longer than about a minute practically pointless. Still, with the level of light pollution, even a minute’s exposure creates a mostly orange image.

Anyway, I had one usable image…

DSC 0095
Original image.

As can be seen, the galaxy itself is quite a subtle feature, mostly obscured by the reflected glow of the Oxford light pollution. So, the next task was to try to filter this out and enhance the galaxy within the image. I did this by adjusting the colour curves for each of the three colours and then adjusting the overall curve.

M51 full scene 2
M51 full scene 2

As you can now see, the light pollution has been greatly subdued and the galaxy stands out far greater. You can still see an artefact caused by the optics of the telescope, the subtle ring of orange with a bright dot in the centre, but this can’t easily be removed.

All that needs to be done now so as to make it an instructive image is to crop, flip (so as to remove the inverting of the image caused by the optics) and annotate…

M51 annotated cropped
M51 annotated cropped

And there it is!

Not quite as good as you’d get from a professional set up but adequate to show the supernova.

The making of an observatory

Quite soon after the purchase of my telescope last August I determined that the time and effort it took to deploy the ‘scope and set it up meant that most clear evenings weren’t going to be able to be utilised. Almost as soon as I’d got it all ready it was time to pack things away again, or the clouds had rolled in. I needed a fixed observatory which would allow me to start observing quickly.

After doing research on the ‘net, in early October I finally plumped for a 6ft x 6ft rolling roof shed from Alexander’s Observatories and sent an e-mail asking for a quotation. At the same time I did the same for the patio base foundation from a local landscape gardening firm, N.V.Firmin. Little did I know how long both of these stages of the project would take. In fact, I imagined that there could be a possibility of having it functional by Christmas.

Well, at least the landscape gardening firm got back to me quickly. However, after getting the quote I was a little disappointed to learn that the start date for the works would be after Christmas sometime. Still, having not heard anything from the observatory company I wasn’t too worried about the delay.

Time ticked ever onward and October became November and November became December. Finally, over two months after my initial contact, I got a reply from the observatory company. To be honest I was expecting never to hear anything at all at this point and was starting to look at alternatives. Still, the quote was good so I gave the go-ahead and sent the deposit, which was cashed on Christmas Eve.

Everything went quiet for a few weeks and it wasn’t until the end of January that I heard from the landscape gardening company. Typically they wanted to install my patio and fencing the weekend I was away down in Cornwall for my and my Dad’s birthday. (Don’t you love the way life works that way?). Anyway, they started work the day before I left so I was able to survey their markings on the lawn after I got home (in the dark) and made amendments. For good measure I drew a sketch plan and taped it to the inside of my patio doors. I was very glad to discover after my return that everything was in order and a very nice job had been made.

Early February: The patio is almost complete. (The hole is for the pedestal foundation.)

At this point I had assumed that the observatory company’s quote of 8 to 12 weeks for delivery was still on track and that soon I’d get the template for the pedestal base foundation. However, I’d not heard anything since before Christmas, so I sent an e-mail informing the company that the base was ready and could I please have the template…

Another month passed and I was about to send another e-mail when out of the blue the template appeared. It was now 10 weeks after I’d paid my deposit and was getting a little concerned that I hadn’t heard anything more.

A couple of weeks later I sent off another e-mail and was surprised to get a reply back within three days informing me that work on my build would be starting in a couple of weeks and the delay was caused by a number of large observatories in the queue before mine. This, I assumed, meant that the timer for the delivery of my unit would then start, i.e. it would be 8-12 weeks from that point. I was not that happy.

You an imagine then the pleasant surprise I got when just a couple of weeks later I received a text message asking if it was OK to deliver the shed the following Thursday. Of course I said yes!

So, after months the day of the observatory arrived… 7th April, 2011.

Nick duly arrived at 8:30am, not long after his ETA and surprising seeing as he had driven directly from Norfolk, and he started right away… with the help of the first coffee of the day.

8:35am: The base goes down. (Note the first coffee of the day.)

Due the relatively small size of the observatory Nick was able to prefabricate most of the parts and carry them all complete in his van, so in came the base and quickly the chipboard floor panels went down, cutting a hole for the pedestal.

8:47am: Base complete, pedestal hole cut.

It didn’t then take very long until the walls came in one at a time, they were lined with single ply and the observatory started to take shape.

9:48am: The walls are up.

Nick at this point was on his third mug of coffee, along with biscuits. It’s thirsty work, especially when it’s the hottest day of the year so far and the area’s a bit of a Sun trap.

The next part of the build was to install the supports for the roof rails and the rails themselves. Basically, the supports are just 75mm fence posts. The horizontals slot into recesses in the walls and are supported by other posts at the most distal end from the shed.

11:18am: The roof rail supports are being fitted.

Once these were complete and the aluminium tracks installed it was time to install the roof. The main wood lattice structure was delivered as a single unit. Onto this was screwed the part of the southern side of the shed which slides with it before, finally, the wheels were installed. The whole thing was then lifted by the both of us onto the shed.

12:15pm: The roof structure is on.

The roof was now fitted with chipboard sheets which were then covered with roofing felt before more shuttering was installed at the gable ends. The project was starting to look almost complete. More coffee helped… And most importantly, the roof rolled.

2:05pm: The roof rolls for the first time.

From this point on things slowed down a little as it was all about installing the final details such as the door, the roof locks. Once these were done it was time to bolt down the pedestal.

3:10pm: The pedestal is installed. Build complete.

And so, by half-past three the installation job was complete and Nick was on his way back to Norfolk.

I spent the rest of the afternoon and evening setting up my telescope for the first time in its new home. I had to rotate the pedestal by one bolt hole so that it was closer to being aligned north-south and then level its top.

Although the basic structure was now complete there was still no power in there and most importantly the strut which joined the two rail supports together was rather inconveniently at nose height. This would be rather tricky to navigate in the dark so I needed to raise it above head height. Also, I wasn’t happy with having the chipboard floor exposed to the weather and so I decided to clad the base with some wood cladding. Another inconvenient problem was that the eastern folding panel was too close to the ‘scope and hence couldn’t be folded down.

All these problems were fixed the following weekend. I used a sledgehammer and a block of wood to ease the whole observatory 5cm away from the house, relieving the folding panel problem before re-engineering the strut and bolting the legs down.

The Weekend: The finished product, well almost.

And so it’s finished… well almost. I’ve still got to paint the inside and then there’s the proper final alignment of the ‘scope mount but it’s mostly there. I certainly didn’t expect last October that the whole project would take six months to complete.

But does it meet my requirements? It would be a bit sad if it didn’t. Well, let’s say that I can now go from deciding to go out to do observation to getting the first object in the eye piece in a little over four minutes and it takes a similar amount of time to close things down again. So, yes. A definite improvement on the 40 minutes it took previously.

Enthusing teen minds: Why today’s computers won’t create tomorrow’s programmers.

The recent 30th anniversary of the launch of the Sinclair ZX81 and the subsequent post on his blog by Jim Finnis brought back to me a recurring thought that today’s computer technology is the antithesis of that required to enthuse a teenager to want to discover and play.

The computers of the early 80s were a blank canvas. You plugged them in, switched them on and (hopefully) the input cursor blinked at you. There was no decoration, no clutter and it was something waiting for YOU to do something to it.

Not only this but with the manual which came with it a 13 year old could within 5 minutes print their name on the screen. Within 10 minutes, at least with the second generation, make a funny noise. And within half an hour he or she could have his or her name scrolling up the screen in different colours whilst making unmusical noises and annoying their parents… they were hooked!

Now, let’s look at today’s technology…

The desktop or laptop computer takes an age to start up (i.e. more than 5 seconds) and totally insulates the user from what it is.

Smartphones are usually on all the time so don’t have this problem. Similarly tablets.

They’re immediately brimming full of functionality all vying for your attention, but it’s also incredibly locked down. You can do absolutely anything… ANYTHING as long as it’s what the visionary who steered the programming teams thinks that you should want to do. Woe betide you if you want to do anything different. It’ll either ignore you or give you an unhelpful suggestion in a dialog box. You can be creative, but only in the ways you’re told you can be.

So, what about the art of programming?

Well, on tablets and smartphones forget any native fun. Apparently this is too subversive. On the desktop it’s only slightly better (and I’m not singling out any desktop OS here). What are your options?

Well, on MacOS and Linux you can open a shell window and all sorts of interpreters and compilers are available and all sorts of graphics libraries to use with them too. You would think that this would be the ideal playing ground. Sorry to burst that bubble. It’s a great playing ground if you’re already a programming expert. It’s like taking a 5 year old into an engineering workshop, sitting him down and then complaining when he doesn’t build a car as he had all the tools available to him to do it and hence it must be his fault.

No, these environments are hopeless to teach and enthuse. There’s so large an energy barrier that it’s too daunting to even try. Also, how many lines of code in one of these modern development environments would it take to do the equivalent of the following?: 

10 FOR x=1 TO 100
20 FOR y=0 TO 7
30 INK y : PAPER 7 - y
40 BEEP 1,y
50 PRINT "Noisey coloured text"
60 NEXT y
70 NEXT x

I bet you’ll find that it’s quite a large number of line of code using all sorts of weird and wonderful libraries, possibly some non-standard ones to do the sound and a whole lot of code to manage the framework to create a window with the correct attributes and define the font etc. Hopeless!

Oh, and when it comes to drawing lines and circles etc. Oh dear.

Of course a great many people think that a computer with similar functionality to the old BBC Micro or ZX Spectrum would never be able to compete in the mind of a teen when they have all that touch-screen goodness and Angry Birds to play with. I beg to differ. It was most delightfully illustrated that this is profoundly not the case in the second episode of the BBC’s “Electric Dreams” series (unfortunately not available to watch on-line) where the family was given a BBC Micro to play with. The teenage son brought his best friend home from school to play with it and they thought it was awesome. They liked that it was a blank sheet that they could make do what they wanted and not be told what they should want to do by the device. And, of course, what they wanted it to do was make silly noises and write their names on the screen in different colours. It sparked enthusiasm!

So, what can be done?

First of all we need to ignore the idealists who think everyone should start their programming life learning something worthy and object orientated. Once the kids are hooked they can learn that later. Also, that’s not how peoples’ minds work. You don’t see object orientated recipe books for a reason. Also, however annoying to the seasoned programmer, line numbers help understand the sequential way that programs work. In other words, the early 80s micro BASICs got it mostly right. BASIC does stand for “Beginner’s All-purpose Symbolic Instruction Code” after all.

Firstly, any system which is going to enthuse also HAS to have as its core functionality the “5, 10, 30 minute” teen grabbing fun element outlined near the beginning of this post. Without it the whole thing’s lost. Any system would also have to allow growth. Just as BBC BASIC allowed the nascent programmer to grow into using procedures so should any new project, and possibly more, such as variable typing, scoping etc. Line number could be made optional in an advanced mode.

Secondly, the freedom of the code itself is far less important than the freedom to discover, so any project should not use a viral license such as the GNU Public License (GPL) but instead use something such as the BSD license.

Thirdly, and helped by the above, the core should be written in a platform neutral way with the platform specific interface on top. In this case, probably the best platform to use would be the GNU compilers and specifically that implementation of Objective C with the QT libraries to interface with most operating systems (except, notably, Apple systems, especially the iPhone/iPod/iPad).

The biggest fly in the ointment with this whole pipe dream is that I just don’t have the skills to develop such a system. (Another would be getting people such as Apple to allow the system to be made available via their App Store type portals.)

So, anyone interested in starting a project? 😉

The horror! Scientific code and how not to read your arguments…

Over the years I have seen many, many examples of poor programming practise, usually kludges and quick fixes but today I saw the most horrible code for reading in command-line arguments in a C program ever. I just had to share the horror…

   if ( (argc-1) < 5 ) {
	[ Usage error response code removed]

   /* read in command-line arguments */
   numFiles = (argc-1) - 6;
   sscanf( argv[ numFiles+1 ], "%s", insFileName );
   sscanf( argv[ numFiles+2 ], "%s", outFileName );
   sscanf( argv[ numFiles+3 ], "%d", &outType );
   sscanf( argv[ numFiles+4 ], "%hd", &windowStartTimeCodeword0 );
   sscanf( argv[ numFiles+5 ], "%d", &newStartLine );
   sscanf( argv[ numFiles+6 ], "%d", &newEndLine);

Now, where can I start with this? Erm, I’m a bit dumbfounded actually.

Not only does the test for the incorrect number of arguments test for the wrong number but then it uses an index from the last value to reference the other values! Of course, this means that if the wrong numbers of arguments are given then the values are put into the wrong variables. Worse, that could be read from memory the process doesn’t own.

And there’s more.. it blindly sscanf()s them into variables.

Now, you may have seen that if one argument is left off the command line the input file now becomes the executable itself and the output file is actually the input data file. This is how this came to my attention. Trying to debug the program for a student it was found that it wasn’t reading the data correctly… and the data file was mysteriously emptied of its hundreds of megabytes of data each time the program was run. Oops!

So, dear readers, have any of you ever seen a worse command line parsing code segment?

IPv4 addresses almost gone, IPv6 not finished yet. Oops!

As has been noted very widely the last couple of large blocks of Internet Protocol version 4 addresses have been assigned to the local distributors and rightly there have been a large number of people stating that we need to get ready for the transition for IP version 6.

However, there are a few niggly little problems due partly to do with IPv6’s design and partly by tardy implementation, neither of which impact upon the general public and their edge networks but will impact upon the security and management of more corporate networks.

So, what are these two problems? Well, they’re both to do with network address assignment, one of which is a foolish design decision in the protocol itself which has a whole host of unintended consequences related to it.

The feature I’m talking about here is the stateless address assignment where a client machine will self-assign its address and self-discover the route out to the wider Internet. On the face of it it seems like a brilliant idea which will liberate the normal user from worrying about setting up IP addresses and all that tedious and confusing networking stuff, it all “just works”. Brilliant! And, in a perfect world, where everyone is smiley, helpful and trustworthy it would be. It’s a pity that the real world isn’t like that. Having said that, this doesn’t really affect personal networking within peoples’ homes but it does greatly affect the security and policing of corporate networks.

At this point it’s probably best to describe how security and policy are implemented, with regards to network addresses and packet routing in IPv4 networks so as to allow you to contrast the differences and the problems inherent in the self-assigned address world of IPv6. Currently a computer can either be manually assigned an address and network route which then has to be configured directly on the computer in question or it can be assigned automatically from a centrally managed Dynamic Host Configuration Protocol (DHCP) server. In the latter case it’s not only the network address and route information which can be given to the computer but other information such as its host name and various other items which it can use to interact correctly with the rest of the network. The centrally managed DHCP server can also tell any computer it doesn’t know (or the administrators don’t want to have network access) to bog off and hence not get network access. Using this very useful system administrators can assign different outgoing network routes for different sets of client machines which can help with load balancing and various other advantageous policies that only humans with an overview of the whole network can see.

As you can see, IPv6’s self-assignment of addresses and self-discovery of network routes by-passes all this control. If you add to this certain client operating systems being “helpful” and offering network tunnels out of the current network for IPv6 clients to the outside world and offering their services as routers it becomes a security nightmare as local outgoing firewall policies and protections are subverted.

Now, this problem has been foreseen, if belatedly, by a group who have, against the uproar of the IPv6 purists, defined an IPv6 version of DHCP. (Note: the purists hate it because it breaks their ideological tenet that all network peers should be equal and free to do as they wish.)

So, surely this means that IPv6 is ready? Erm, no. You see DHCPv6 is only currently a paper exercise. The technical details have been hammered out and the specification documents (RFCs) have been posted but there are no implementations out there. Ooops!

So, what does this mean for the whole IPv4 to IPv6 transition? Well, it means that internal corporate networks will not be able to change to the new protocol and will be forced to live behind an IPv4 to IPv6 network address translation (NAT) gateway. (Note 2: IPv6 purists cringe even more about this technology, they see NAT as the spawn of the devil as it stops all peers being equal and being able to talk directly with every other.)

I can foresee the transition from IPv4 to IPv6 being a long one with to start with only those machines which live in the no-mans-land where external services live and the core Internet changing over to IPv6 and everything else being behind huge NAT gateways. Internet Service Providers (ISPs), whose customers don’t generally have fixed network addresses anyway, will sit all their customers in IPv4 bubbles and this state of affairs will ossify. All web sites will be forced to use IPv4 compatible addresses.

Eventually, after many years, all the tools and security issues with IPv6 will be sorted out and slowly, very slowly, the corporate world will change their networks one by one, but there will always be “legacy” IPv4 networks in there, well at least for 20 years or so. For ISPs the transition will be quicker. They’ll probably have to begin with a separate product for IPv6 users or merely provide IPv6 gateway routers to new customers (quite probably to begin with using an IPv4 NAT bubble for the home network as quite a bit of embedded A/V equipment will not be IPv6 capable). I can foresee that even this transition will take a good decade. During this time all web servers will have to be on IPv4 mappable addresses.

It’s going to be a very long haul and expect things to break horribly.

Why, if time travel were invented today, it would be pointless and deadly.

I know it’s a random subject but bear with me. This is a little thought experiment on the subject of time travel and, if it were miraculously invented today, would be totally pointless and deadly, at least for humans.

First of all, let’s look at what I mean by “time travel”. Basically, my definition is that it is travel forwards of backwards in the fourth dimension of time by popping out of space-time in one temporal location and popping back in another. i.e. there is no spacial movement. This assumes that there is actually a fundamental space reference frame within the Universe which would probably change size and shape caused inflation and local gravitational field effects.

So, why do I postulate that it would be pointless today?

Well, let’s think about this. We are not stationary. We have velocity relative to everything except the few things around us which happen to be enjoying the same small area as we are. Even objects you can see a few feet away from you have a very slightly different trajectory to you because of the curvature of the Earth and its spin and the orbit of the planet around the Sun and also the orbit of the Solar System around the galaxy. So, if you were to just pop out of space-time just for a few minutes you’d find yourself either high in the sky, possibly even in space, travelling in an awkward direction or, even worse, suddenly underground squished by the planet you’ve hit at a couple of thousand miles per hour. Ooops! Paraphrasing Douglas Adams, not a naturally tenable position for a human.

This means, of course, that before you can use your new time-travel machine first you need to build yourself a nice inter-planetary capable space craft. At least you’d not have to worry about getting off the planet but you would have to make sure that your time jump was long enough to make sure nothing was in the way when you popped back into reality.

Well, this would be fine as long as you had a decent inter-planetary drive and enough time to travel back to Earth. The problem comes when you want to travel for more than just a few hours, or maybe days. You see, the further you travel backwards or forwards in time the further you will be from Earth when you arrive. After a few days you’ll be finding yourself popping back into existence outside the Solar System so you’ll need not just a fast inter-planetary ship but an inter-stellar one. If a fast inter-planetary craft is hard to come by at the moment then a nice inter-stellar one is even rarer.

Of course, there are other problems when you start moving very far from where you began, the most notable of which would be the change in the distortion of space-time due to gravitational field differences. Goodness knows what the effect would be when popping out of the high gravitational field distortion close to the Sun, Moon and Earth and then popping into a far “flatter” field in inter-stellar space. Would the instant change in your own space-time bubble be detrimental to your survival or physical integrity? I don’t know. Of course, this effect would be amplified greatly if you made large time jumps as space-time itself would have changed size due to the expansion of the Universe.

Overall then, time travel, other than the usual one second per second forward, is probably not a good idea, and likely to be a tad unhealthy at that. It’s probably why you’ve not met any time travellers yet.

White (or rather blue) van man damage.

It’s not been a good week for my car. Sometime on Wednesday, whilst it was sitting on my drive, a good 10ft (3m) from the entrance it was hit by another vehicle. It was little more than a rub but it has caused some paint damage and also subtle denting to the rear, driver’s side wheel arch and passenger door. This is a right pain.

From the paint left behind from the other vehicle and the other evidence it looks like it was a dark blue (the same sort of colour as “Home Delivery Network” use on their vans) and the height of the bumper was that of a van. From the angle of the impact it seems that the vehicle was using the wide driveway as a turning place.

The worst thing about it all is that he/she didn’t stop and leave their details. Still, it’s definitely not worth claiming on the insurance as for the next five years I’d be paying far more than any potential repair cost, even though there is no way that it could have been my fault. Such is the way that insurance companies gauge risk.

As I said, what a pain.

BBC News: Sensational and missing the real point.

Having watched a news item on the BBC Ten O’Clock News about the chemical sludge leak in Hungary ( I became quite annoyed by the sensationalist and wholly inaccurate reporting of the toxic dangers inherent from the torrent of contaminants.

The first part of the description of the ingredients was fine, it said that the main component was iron oxide, which was clarified as being rust. After that it became a scare story. You can see by the descriptions in the graphic describing the chemical breakdown of the sludge in the article referenced above how bad it was.

But wait a minute! Let’s look at this information more carefully and remind ourselves that this is a fully hydrated environment as well. I’ll take the ingredients one at a time:

  1. Iron Oxide: Annoying but harmless.
  2. Aluminium Oxide (Al2O3): Well, reasonably inert. There is actually a possible link with dementia with long-term ingestion. Nothing like Aluminium Sulphate, which was what caused the Camelford incident.
  3. Silicon Dioxide: Wait a minute.. note the asterisk. The footnote says that actually it’s NOT silica (i.e. quartz), it’s as part of sodium and aluminium silicates. That’ll be clay minerals then.
  4. Calcium Oxide: Hmm.. Quicklime, in a hydrated environment?! Doh! No, plain old lime, Calcium Hydroxide. Not good for plants but not exactly the worst contaminant in the world. In the environment it’ll probably react with CO2 in the atmosphere and become that well known toxin, calcite… limestone.
  5. Titanium Oxide: That well known toxin used to cover mints and other sweets.
  6. Oxygen-bonded sodium oxide: Hmm.. so, it’s not just an oxide, it’s extra oxygen bonded!!! Oh dear.. epic fail number two. In water this would quickly become NaOH. A bit horrid… will turn fat into soap. A slippery customer. Not a long-term problem though.

Now, what was not mentioned in the TV item and is relatively marginalised in the written piece is the problem of heavy metal contamination. This IS the news worthy part of the contamination problem and it’s been almost totally missed by the reporter. The problem, I think, is that because the concentrations in the sludge are low relative to those headline grabbing amounts handed to the reporter in a press release from the chemical company they don’t sound important to a layman. However, they are the long-term health legacy items.

Mentioned in the written article are mercury and arsenic. I’m very much surprised that cadmium isn’t mentioned seeing as these are essentially mine tailings by proxy.

So, all in all a rather big failure on the part of the reporter who, because of a lack of scientific knowledge, not only made an arse of himself and the BBC but also missed the whole real news story.

Astrophotography, the beginning.

As mentioned in a previous post, I’m recently bought a new telescope with the thought of using it for astrophotography.

Now, seeing as the last part of the order turned up a little over a week ago, the equatorial wedge, I’m finally in a position to start on the project in earnest. To this end I went out shopping on Saturday for a camera and a machine to drive the camera and the ‘scope.

Having read quite a great deal and seen images which other people have managed to take, I opted for the Nikon D90 as the camera body to obtain. Currently, it’s probably the best time to get one of these cameras as it is about to be replaced by the D7000 and hence the street price is at its lowest. Waiting for the D7000 to appear would be counter productive as it will not only be at a premium price which is almost double that of the D90 but also doesn’t have anything really to help with the task at hand. (The main improvements over the D90 are in the realms of auto-focus and a more robust, and heavier, body.)

Unfortunately, because it is about to be replaced it is becoming scarcer, which meant that I could only find it as part of a kit with a lens I don’t actually need. Oh well.

On the control machine front, I picked up a netbook. The twin-core, 1.6GHz Atom processor powered Acer Aspire-One 533 should be ample for the task. There’s not a great deal of processing power required to control the camera, acquire the images or run Stellarium or similar to drive the ‘scope. I just need to get a serial cable now.

Anyway, Saturday evening was a beautiful evening with crystal clear skies, which gave me a good opportunity to have a first experiment.

The results? Well, OK for a first attempt. It’s very difficult to get a good focus when looking though the viewfinder. My first target was the Moon:


Not too bad for a first attempt…. Then over to the Dumbell Nebula:


As you can see, this 60 second exposure really shows up the problem with light pollution in the area I live. I’m going to have to look into getting a light pollution filter.

Finally, I spent a little while trying to image Jupiter. The best I managed was this:


I’m definitely going to have to look into ways of getting a sharper focus. Not all of the fuzziness is caused by atmospheric disturbance.

Anyway, following on from my photographic exploits I noticed one of the Jovian moons, Io, coming out from behind the planet. It’s amazing but you can actually see it move relative to the planet with the gap visibly changing in only seconds. It must be moving at quite a speed.

Still, I’m not likely to get another chance to play in the near future, looking at the weather forecast. The next items on the shopping list: landscaping with paving and a rolling roof observatory such as this: