Tuesday, 29 October 2013

Astrophotography part 1- equipment

Have you ever tried to take photographs of night sky ?

You will need certain equipment to get some decent results. I don't mean using a telescope just your camera

1. Tripod
2. Cable release or preferably a Timer remote for longer exposures
3. SLR camera
4 .Wide angle lens
5. Lots of good clear nights
6. Patience
7 Warm clothing
8.Lack of wind

A solid tripod and preferably one with a hook on the centre column so you can hand a bag to help stablise it even further. Try to set it up on a solid surface and not on grass and if possible a sheltered area away from wind.

Cable release
Most camera setting will allow you to go down to a 30 second shot. What you need to do is to use a cable release to minimise the vibration, better still use a timer remote which allows you to set long exposure for up to 99 hours and number of photos to 399. I use the TC-2 for the Nikon D7000

As noise is a major problem when taking long exposures it is best to use a DSLR, the best but most expensive is a full frame camera but I usually get reasonable photos from a DSLR DX (cropped sensor camera such as the Nikon D300, D7000 and even the new D7100. It also has a good range of ISO settings and a good processor

Wide angle lens
You need as much light in the camera as possible, so a fast lens is preferred. I use the Tokina 11-16 mm f2.8 lens, which isn't the fastest but is very sharp when using it full opened. You will have to close most lenses down to say f/5.6 to get a sharp photo

Clear Night
This is the most frustrating, you can have all your equipment ready, but then you have no clear nights for days on end. Then when you do you are usually committed to something else. as Shetland is near the coast the weather systems seem to move quickly overhead, so although it may be cloudy now it could be clear in an hour. You will need a decent gap in the clouds to get some long exposures.As the nights are loner in Shetland you will have more chance of a decent spell.

Yes have lots of this, you will be stood about alot when you have set up the camera, so why not take your ipod with you to pass the time

Warm clothing
Its surprising how many people don't go out prepared, its going to be at least a few hours outside and the last thing you want is to be cold, you loose concentration and the will to be outside, so wrap up warm and take a hot drink with you.

Lack of wind
Shetland is not normally a good place for still weather, well it does happen some times. But you can find a sheltered spot and use a weight on the end of your tripod to help. Once you start a sequence of photos then it could be rattling them off for an hour solid. You could also use yourself as a wind break, if you position your self right.

You will need at least one , try a head torch will will free up your hands. You will need one to set up the focus and one to move about. A Red cover is better and you want your eyes to adapt to the darkness

Try to plan your shoot ahead and do a recce during the day to see whether things are. You don't want telephone wires crossing through the photo and if possible find an interesting object for the foreground such as an old croft or some large rocks or go near the sea

In the next blog we will talk about how to take the photos.

Friday, 18 October 2013

1 Billion pixel camera

Everyone seems to be hung up with megapixels these days. I even talked to someone the other day who thought his 12 Million pixel phone camera was better than a 10 million DSLR. They fail to take into account that it is the sensor size that influences the size of the pixel. The larger the surface area the larger the pixel is, so the phone sensor is very small, hence very small pixels which produce a lot of noise, not really noticeable until you look away from the screen and start to try and enlarge.

Everything is getting better but you also have to look at the processor as well, if the camera can take great photos then the processor is needed to get the information out of the image, which only the high ended DSLR cameras have.

So when I heard that a 1 Billion pixel camera was to be launched then it raised a few eyebrows. Reading further it was clear that this was special, very special if fact out of this world. Yes it was the new and largest camera to be launched into space. If fact this will take place next month.

To get to the 1 billion pixels, it is in fact 106 CCD cameras linked together, with a sensor size of 0.38 square metres, the largest imaging system deployed into space. Its lenses are in fact two telescopes and these will be all located on the `Gaia' . The European Space Agency's Gaia mission will be the most sensitive astronomy mission ever.

The plan is to study the structure and dynamics of our Milky Way. It will map the Milky Way in 3D, observing around a billion stars, which may sound alot but in fact this is only just over 1 % of the stars found in the Milky Way.

So the image size will be enormous, and to cope with the data an extensive pipeline of information will be analysed by centres in Cambridge, Germany, Spain, France and Switzerland. A bit bigger than my hard-drive  !!!!!!!!

Friday, 11 October 2013

Clear night, cloudy night

When we get to October I always look forward to photography trips out into the night air. Especially when it is cold, because then it is sometimes clear skies. Something so far we have not had a lot of recently. Just one so far, and guess what we had already made plans to go out so that was one lost. The weather forecasts always seem to get it wrong, often they indicate a clear night , then having made all the plans to go out to get some photos the cloud rolls in and another opportunity hits the dust.

It must be great to be in Australia or the desert area in America where the dry air gives rise to clear skies on many days, but we have to make the most of any opportunity in Britain.

When we do get a clear night it is often when the moon is full so the sky is filled with light, again far better when the moon is small. With general light pollution another problem you may well ask why bother.
I can only say that once you have been out, even to an area close to a city, which is not the best, the sky takes a hold on you.

You cannot avoid looking up and seeing a multitude of stars and hopefully planets if you can pick them out. It may take five minutes for your eyes to get accustom to the darkness then you see even more. So although I may get out on only a few nights but each one becomes extra special and you appreciate it even more and don't take it for granted.

With so much to see, and in Shetland with the chance of seeing the aurora you have got to make the effort to venture out. The time always passes so quick and having done so little photography its then a time to look back on what we have captured and what we plan to do next.