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Equipment

               

Camera
The older and less automatic the better. Today's camera's may have a lot of feature's but most of them lack the fundamental feature required for astrophotography. They simply don't have the capability to open the shutter for long periods of time. If you do not already own a camera that is suited to astrophotography here are a few tips that may help you decide what to buy.

Must have a manual exposure setting. It will have a 'B' setting on the exposure dial.
Avoid camera's that rely heavily on automatic features like aperture priority, and automatic frame advance as these cameras are heavy on batteries. These batteries could give out at any moment, particularly during a long exposure!
Should allow interchangeable lenses.
Auto Focus is not required as focus during astrophotography will always be set to infinity. Infinity is marked on the camera lens as .
The shutter release should have internal threading to allow a cable release to be attached.
Classic SLR cameras are best suited for the job. These are easily picked up second hand at relatively low cost. Even the largest camera shops have a good range of second hand equipment for sale.
When buying second hand equipment always make sure you get some sort of guarantee. Even if it is only for a short period of time.
Good examples are the Canon FTb QL or the Olympus OM10
              
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Lenses
Good quality, second hand lenses are also relatively easy to get hold of. Most camera's come with a lens but this may not necessarily be suitable for astrophotography. The following points may help you attain lenses that are up for the job.
Focal length is the distance between the optical centre of the lens and the film mounted in the camera. This measurement is how lenses are classed and is marked somewhere on the outer casing of the lens. For example, 50mm or, in the case of zoom lenses, 80-200mm. In general 50mm lenses has the best light capturing capability.
Aperture, or f-number, is the lens opening. The wider a lens can open, the more light it can gather. The best lenses offer adjustable aperture which helps control the amount of light that that can pass through the lens. The lower the number, the wider the opening. For example the 24mm Exakta lens has an adjustable aperture of f 2.8 to f 22.
Your lens should come with some sort of guarantee so get snapping straight away. Shoot a few films, not necessarily of the night sky, but try to get a mix of dark and light subjects. Check the results for any repetitive anomalies. These may be nicks or scratches in the optics that were not noticeable at time of purchase. If you find any, take the lens straight back for a refund, taking your results as proof.
For astrophotography try to avoid zoom lenses. They normally have narrower aperture settings and so gather less light.
Different focal lengths can give variety to your shots. With a wide angle lens, say 24 or 28mm detail will be less apparent but a larger area of sky will fit into a single frame, plus the shutter can stay open for longer as the movement of the stars across the sky will be slower through such a lens. If you want to own more than one lens, make sure they are of different focal lengths.
Auto focus is not required as the lens will always be set to infinity, plus manual focus lenses are normally much cheaper.
       
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Tripod
Your tripod should be sturdy. It should be strong enough to withstand a light breeze and enough to handle any shake created by the camera shutter......
.... but at the same time, as light as possible especially if you are going to be carrying it over any great distance.
Extendable, to at least your head height. Cold and possibly damp nights are no time to be crawling around on the ground.
It needs to be flexible. A pan and tilt head will allow you to set up the tripod once, then all you will have to do is move the camera to get all the shots you require no matter where they might be in the sky.
       
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Film
There is so much variety out there. Different companies offer different films at different speeds for different prices. Experiment with the different brands and then stick with the one that gives the best results for you. Even the most popular brands are available at reasonable prices, especially if you buy over the internet, so don't feel pressured into buying cheaper alternatives.
Film speed is its ISO rating. The higher the number the faster it is. For example, light will be captured much quicker on an ISO 400 film than it would an ISO 100 film. However, as film gets faster the results get grainier. An ISO 3200 will capture a lot of light, very quickly, but the result will be very grainy. For the best light capture without loosing impact due to strong grain, use ISO 400 film.
As far as light capture is concerned, you will get similar results with a same speed black and white film as with a colour film. The only real difference is, well, the colour. With black and white film you will miss out on all the different colours of the stars and planets.
        
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Extra's
A camera, lens, tripod and film are all essential to astrophotography. The following are all almost essential. In other words, they are nice to have, but you could probably manage (just) without.

Cable Release
A cable release allows the shutter of the camera to be opened and shut at will, without even touching the camera, therefore dispensing with any camera shake due to holding the camera during an long exposure. 
Lens Hood
Prevents stray light from impacting your shots and reduces the risk of lens flare. For example, if a bright moon is just outside the frame of a picture, using a lens hood will reduce the risk of its light being picked up on the film during the long exposure.
Star Maps / Planetarium Software
These can be used as a reference for what to shoot. They will tell you what will be where and when. Get to know the night sky and improve your shots. Planetarium programs are also a useful tool in tracking the planets and helping prepare for planetary conjunctions. Almanacs also offer details of celestial events years in advance.
Cleaning Equipment
Keeping your equipment clean is essential. Use a pressurised canister of air to blow away loose dust from inside your camera as well as the back and front of your lenses. Keep the front of your lenses polished with a washable lens cloth.
                   
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Credits: ©  Ian Robson