• Night sky photography

    Surprisingly good quality, wide-angle photographs of the night sky can be made by almost anyone using readily available single lens reflex 35 mm traditional film or digital cameras.This method of photographing is known as Astrophotography.

    1. Mount the camera on a sturdy tripod. Load the camera with high-speed (at least ISO 200) film, or set the digital camera speed to between 200 and 800. (400 film speed and higher will be noticeably grainier.)
    2. Turn off the autofocus mechanism, and manually set the focus ring of the lens to just before infinity (or landscape/distance autofocus setting). If you are including a foreground in your image, make sure to take two images, one with the stars in focus and one with the foreground in focus. These can be combined later in most editing programs.
    3. Set the shutter speed to either the bulb setting, or a range of settings between about 2 and 30 seconds.
    4. Point the camera at the desired area of the sky, trip the shutter (preferably using a cable release, or the camera's self-timer in order to minimize vibration), and keep the shutter open for the desired length of time.
    5. Set the widest aperture, lowest f-stop for your lens.


    Tips:
    For best results, stop down the lens from its maximum aperture (often f/1.4, 1.8 or 2.0 for film cameras) at least 1/2 to one full stop. This will (i) reduce the uneven lighting across the image known as uneven field illumination, and (ii) reduce aberrations in the star images that can make them appear bloated or misshapen.
    In addition to leaving the shutter open for many minutes to hours, there are other things that can create stunning astrophotos using only amateur equipment:
    Don't limit your framing and composition to just the sky. Include some foreground objects (you and your binoculars, trees, an observatory). If there is some stray light about (which you should be trying to avoid), it may be enough to illuminate your subject. Otherwise, use a flashlight and literally "paint" your subject with it, or use car headlights as a flash source. The best thing is, your exposure will be at minimum 30 sec, and probably much longer, so you have time to start your picture, apply your flash or torch, then wait for the exposure to finish. This may take some practice (so record everything you do) but you should be able to get bright stars/star trails AND bright foreground subjects.
    Try to catch a meteor shower and leave your shutter open for a good half hour. You might catch many meteors in one frame (but even just one is a thrill to see when you get your shots developed). You can also look for airplanes and satellites in your exposures.
    This one is a little more tricky. Start a 5-10 min exposure in perfect focus (focus at infinity). At increments during the shot defocus your camera by small amounts. The shorter the increments and smaller the focus change the better the result, but this also gets increasingly difficult. The result should be cone shapes (instead of points of light) because the stars will move through the frame as they become larger (de-focused) blobs of light. The reason for doing this: unfocused images show their colour much better than tiny points of light. You will be able to compare the beautiful red/yellow/white/blue etc. colors of the different stars. Also, the cone shapes look slightly three-dimensional and very interesting.
    The faster the film the brighter your stars will look, but also the more grainy your images. As a minimum, use a 400 speed film, but be very tempted to experiment with specialty films (such as 3200 speed).
    Always record your shots in the order you take them. It's almost certain that as many as half your shots will not work. Recording your exposure times and other settings is the only way to improve. Photographers using digital cameras should consult the EXIF data.


    Warnings:
    Earth's rotation will cause the night sky to appear to turn overhead. The result is that, using a stationary camera, within a short period of time the stars will appear as streaks of light on the photograph, rather than the sharp, point sources of light that we see with our eyes. Using a standard 50 mm lens on a 35 mm camera, stars will begin to streak across the film plane after about 30 seconds. Although very striking photographs can be made using exposures of minutes or hours - so as to deliberately show long star trails - most astrophographers either use short exposures on a stationary mounted camera, or else use a motor-driven telescope mount, in order to keep the stars as points of light in the final photograph.
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