Dark Skies

Sark - Where the bloody hell is it? It's a Channel Island, about 350Kms from Paris and 300Kms from London. The island of Sark has become a 'Silver Tier Dark Sky Park'. This means that the visual limiting magnitude is between 6.0 to 6.7, there are other criteria, this is the simplest. The rating is endorsed by the International Darksky Association (IDA) and it was achieved by a resident of Sark that measured and assessed the every light fitting on the tiny island 5.5 sq ams. The island had a head start because there are no cars, so no street lights. The Government of Sark was ready to accept that with the rating comes conditions that will retain the island as Dark Sky Park. The island of Sark is not the only such park, the website of the IDA lists others, some with higher ratings.

I think back to my first ventures in Astronomy, and I can recall dark skies from suburban Sydney. In the night sky I distinctly recall seeing both the Large and Small Clouds of Magellan and the bright band of the Milky Way. I'd say the clouds of Magellan were still visible to the unaided eye as recently as the 1970's. These days the Southern Cross (Crux) appears to be fading and certainly the Coal Sack is almost impossible to discern from Sydney.

The year of 2010 was interesting for Astronomy around Sydney. The Beames Observatory at Linden, in the Blue Mountains gained a Heritage Listing. This included 40 hectares of bushland to assist in preserving dark skies. It is also now three years since the National Trust registered as a Heritage Item both the Night and Day sky over New South Wales. What's happened since - not much

Robot Astronomers

The 'Robot Astronomers' are to rise up. That's the opinion of 'New Scientist'. Here's a link to the article - you will need to register http://www.newscientist.com/article/mg20927954.900-rise-of-the-robot-astronomers.html?page=1 , it's free to register. Obviously I can't re-use their copy. For many years the amateur community has provided a service to astronomy by patrolling the skies looking for variable stars, supernovae, and all sorts of odd events. This article refers to a programme at the Palomar Observatory , see the image.

The upshot is that robot telescopes image the sky and computers then process the data. And then there is some form of Artificial Intelligence (AI) that can recognise the areas of the sky and ensure that the correct regions are processed when the images are compared for changes between observations. What they expect to see is changes in position or brightness. They can build a list of candidate objects from searching through databases of catalogues.

Of course what doesn't get mentioned is that - almost without a doubt somebody has to go out and visually identify a positive. It's still the case that experienced amateur astronomers can simply go outside at night, look up, and see if any stars have changed. It may take a number of years and dedication to acquire and tune these skills, and I'm sure these amateurs can push the robots to their limits.

Of course being a robot could come in useful, presumably I could reduce the set-up time for the telescope. Get the setup correct, ensure that batteries are correctly charged, remember where I put each eyepiece (in the dark), stay up late maybe, better still pack it all away in the early hours of the morning, or before it starts raining or starts collection dew.

Starting to look clear for to-night. Moon rise is 23:15, so there should some dark sky before it rises too high. Although the neighbours stay out late with their yard lights on during the recent hot evenings. The expected weather over Australia Day and the next few days is hot and wet, the satellite photo is clear. We'll just need to wait and see.

The Quest for Power

Over the last twelve months my astronomy has been more of a course in electronics - something that in my university days I saw as nuisance and relevant only to the propeller heads in Elec. Eng. Add to that total and complete colour blindness and I'm sure you'll agree it was probably fairly pointless putting a bunch of resistors and capacitors in front of me. I was and am, much happier at a larger component level.

In the quest for significant amateur astronomy the old telescope was disposed of for a you beaut computer controlled model - a Celestron CPC8. All sorts of back-end gear was added - a filter wheel, temperature compensated focuser, field rotator (just to complicate it). Of course everything is powered and it all can be computer controlled. So everything needs power. All the electronic components use DC power and one objective was to be portable. After a few shake-down runs success looked achievable - soon however some gremlins started to show. The heavy duty marine GEL battery still capable of powering an electric outboard on a small boat - couldn't cope with the draw of most of the gear - OUCH1

So the solution is to use a Laboratory Power Supply, at least when within range of a residential power supply. Still this meant acquiring or building a distribution box for the 12V supply. This was completed with a lot of burnt fingers, cursing and trepidation. All this was fine for 12V requirements, and of course there is the few components that require odd voltages and need a step down DC-DC transformer - simple to say , however fraught with difficulties. The most significant issue is that the excess power needs to be shed and disposed of, and this is done by converting it to heat - well this is simply the outcome. The bigger the voltage drop the more heat. The problem this creates is that the electronics to handle the DC shift are compact, the cooling heat sink fins can be large. Correspondingly the housing box goes from small to large. Anyway the bottom line is a complete redesign but I should achieve a reduction in long cables thus removing another risk factor of something that trip up the scope in the middle of a run.

So I'm still out of action and almost back to step 1 but about to make a come back.

Getting Started

Who knows where this sort of activity may end - is it some sort of slippery slope? All experiments can have a random outcome - sometimes serendipitous, although mostly uninteresting and boring - not necessarily failure just boring. So here's hoping for some interesting serendipitous random outcomes!

Just looking through my observing log the last night I ran up the scope was the 2nd September 2008. Since then most evenings have not been worth it - mostly cloudy, or I attended a commitment such as a Committee Meeting for something - most likely astronomical related. Fortunately Christmas suspends most of these commitments and I get an opportunity to utilise a clear night.

The first topic off the rank is - the weather. I'm sure most people talk about the weather, for an astronomer it's about the clouds. Earlier this year at the Sydney City Skywatchers we listened to a great talk by Julie Evans of The Bureau of Meterolgy. She gave us lots of ideas of how to plan for the weather and told us about The Cloud Appreciation Society.

So far to-night looks like it might be clear - for a change - still about 5 hours to go to twilight. The Sydney MTSAT-1R VIS is showing some scattered cloud coming from the West. The South-East Australia shot shows about a 500Km gap. My guess is it will be line-ball, maybe clear in the early to late morning. It's been a hot humid day so the seeing will be shocking.