Lots of film and lots of patience is the recipe for conventional astro-photography - oh! and a camera and the stars to steer by  helps. My approach is a very amateur one, suitable for short exposures only.

• An essential accessory for astro-photography is a driven  mount of some sort. Web sources point to the Barn-door or 'Scotch' mount - a hinged board, Motor -driven Dobsonians etc. but by far the most popular is the motorised, and often computer controlled, equatorial mount. This is readily available (for money) from commercial sources. I had a modest sized hand controlled mount available and motorised it with components from my junk-box. The R.A.  motor was a stepper motor which was available from Maplins here in the UK together with a driver I.C. and board; the motor has since been changed for a more powerful one from an old disk drive. It needs a clock circuit to drive it - I made one using an NE555 timer I.C.. The hard bit was the step-down gearbox. I don't know what mine came from but it is very ancient.  I experimented with a declination motor but found it easier to simply use the slow motion hand control on the mount. I've since built an Equatorial Mount for my Dobsonian but haven't used it for 35mm film work.

• Alignment of the mount to true North is very important but difficult with  the crude equipment described above - all the mount has on it is a ring sight and bead. Sometimes I get it right, and sometimes not - you never know until you get the photos back from the processor. Sometimes the pole star is difficult to see above the lights of the city so I have set a bearing on a local point on the skyline in daylight which is also visible at night.Yes, it's crude and it wouldn't be accurate enough for serious work using a telescope. A better way is to watch the declination drift in the viewfinder and adjust the polar alignment very slightly - and keep doing it until there is little / no movement. It takes time.

• Exposure times - providing the mount is aligned as described, exposures of up to 2 mins show little / no  star trails when taken through a 135 mm lens at medium to high elevations. Longer exposures are pointless here because of light-pollution.

• Film speed can help combat star trails. Faster film means shorter exposures can be employed although there is also more film grain. I generally use 200ASA or 400ASA  Kodak Gold. Anything faster gets swamped by local light pollution. Why print -film  and not slides ? Because I only have a normal scanner with my computer, not a slide scanner and the next step, below, is essential to the process.

•  Processing - I normally scan in the prints at high resolution. They can then be corrected for colour casts from the processing (astro-photos fool the processing labs unless you warn them but can be recovered in the computer), and more sophisticated adjustments and enhancements  employed using  programs like Paintshop Pro etc. These can make an astounding difference to a seemingly mediocre photograph.  True, you can't put detail in that wasn't there in the first place, but there's a lot waiting in there to be teased out. There are some very efficient dedicated programs available for dealing with astronomy images offering sophisticated enhancement techniques. Some of these are listed in the section on CCD imaging and most can equally well be applied to processing conventional photos once they're in the computer.

• Cameras used are 35 mm format S.L.Rs. because that's all I had. The best for the job is an ancient Praktica which takes screw-fit lenses. It's main advantage is that it has an all-mechanical shutter release. Ones with electronic shutters can cause problems when the tiny battery goes flat whilst holding the shutter open for long durations in the cold. Some cameras will operate the shutter on the 'B' setting with the battery removed (I have one). For obtaining images of star-fields, telescopes and high power lenses are not needed - they only compound the problem of tracking . Lenses with focal lengths between 35 and 200mm are adequate for this type of work. There are a few more essential pieces of equipment - a long cable release to minimise vibration, a loose fitting lens cover that can be removed some seconds after the shutter is opened and the vibration has died down and a watch or clock that can easily be seen for exposure timing (or the ability to slowly count up to 240 without forgetting where you got to). UPDATE - I've now got a digital camera (an Olympus C730) which allows exposures of up to 16 secs with automatic dark frame subtraction - initial results are most encouraging.

• Viewfinders - You can't see much through an S.L.R. viewfinder at night !. I built a simple straight through finder from a cardboard box, some clear plastic and a LED. The image above shows it in action on the camera. In the dark, the inscribed lines on the plastic front are illuminated well, showing angle-of-view frames for different camera lenses. It's not super accurate, but it's a lot easier than the other way.

The clear plastic graticule was cut from an old CD box and the lines carefully scratched in with a sharp knife using a drawing of the pattern underneath as a guide. Knowing the field of view of the lens, in degrees, you can plot this relative to the distance from the spy-hole in the back to the position of the graticule and from that work out the dimensions of the rectangles. The large LED on the top pokes through a small slit so that it aligns with  the edge of the graticule and was masked to cut down overspill. In the dark, only the lines show up if all is positioned correctly. I didn't fit a potentiometer to adjust the LED brightness - I wish I had.

• Examples of photos taken with this set-up can be seen in the GALLERY.

• All my conventional astro-photography shown here has been carried out through camera lenses, not a telescope. This is definitely required for imaging planets and objects which require high magnification and/or much light-collection. My preferred method now of recording the heavens is to use a cheap CCD web-camera - no waiting to develop the film and capable of much more image processing. See this page.

• A final point, unless you're quite an experienced astronomer (which I'm not), it's very difficult to later identify photos of star fields mainly because so much more is recorded on the film than seen by eye.. It helps to take a print of a sky map with you and mark on it the approximate view of each photo taken, exposure times, lenses, film, date and time etc. and then write that information on the back of each print because you'll never remember later.