Astro photography @ Nisargshala

How to Take Great Pictures on a Starry Night

 
The spectacular night sky is something that every human will look upon in wonder at some point in their lives, and with the advent in cheap, high-resolution digital cameras, it’s easier than ever to capture those dramatic moments for yourself.

Know the requirements

Taking photos of the sky at night, or ‘astrophotography’, you don’t necessarily require a telescope to produce breath-taking photos.  However, what you do need is -ideally – a tripod, and a camera at least capable of manual exposure length adjustment.

Many point & shoot cameras have an exposure length up to 15 or 30 seconds.  You might think that the higher the length of exposure – the better photos of dark scenes will be because of the greater amount of light captured. Whilst to an extent this is true, in Astro photography the rotation of the earth means that setting exposure length too high will result in everything appearing as streaks across the sky.

Of course, sometimes this is a fairly desirable effect . Some of the most hypnotic photos of the night sky are taken with a long exposure time to dramatic effect.  However, to capture the night sky in all its beauty, you’ll have to strike the right balance of exposure, ISO sensitivity and aperture size.

Adjusting the ISO changes exposure values, so as you raise the ISO, less light is needed. Each time you double the ISO value, the camera needs only half as much light for the same exposure.  The trade-off however is that pictures can become considerably more grainy if the ISO is set too high.  On Digital SLR cameras that have sensors with larger pixels, it’s much easier to take quality night photographs with an ISO setting of 1600 or higher, but whether you use a DSLR or compact camera, it has to have manual ISO control so that you can find the best compromise of brightness and quality.

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Using the right camera

If you’re fortunate enough to have a DSLR camera already, then you’re already well equipped to start photographing the night sky.  Alternatively, there are quite a number of compact cameras available that have a ‘manual’ mode, allowing you to adjust those all important settings.
Some cameras will be advertised as having a ‘night’ mode – don’t confuse this with a mode suitable for astro photography, it usually is anything but. On compact or bridge cameras, look for a ‘P’ or ‘M’ mode that indicates either programmable or manual modes.

A DSLR camera affords much greater control over your photos, and will give the best possible results.  When using a DSLR to photograph starry skies, you will require a large depth of field to ensure everything is in focus, a wide aperture (ideally f/4) and a manually adjustable exposure length (between 20 – 40 seconds).  ISO should be set to 800 or 1600 in darker areas, or closer to 400 in light-polluted areas.  White balance should be calibrated automatically, or alternatively use the ‘daylight option’.

Either use a remote shutter trigger, or use a timer setting to ensure that you are not wobbling the camera when depressing the shutter button.  When considering which lens to use, a 15mm ‘fish eye’ lens or anything with a low focal length – zoom lenses will generally provide too much distortion to photos.

For all cameras, ensure that you are shooting in the highest image resoltition.  There are often a range of different names depending on your brand of camera, but usually the highest resolution is denoted by the mode ‘Large’, ‘Fine’ or ‘High’.  Whatever option is available it’s always advisable to use the native resolution that the camera offers, so with a 14MP camera, ensure you are shooting in 14MP modes.

DSLR cameras offer a ‘RAW’ photo mode which is a format that preserves all of the original data from the sensor – there is no interpolation or adjustment of the image.  These raw images allow the most control over how the data is calibrated, manipulated and enhanced in order to produce the best quality images.

Remember to turn off any red-eye reduction, the flash, and any image stabilisation options for the best results.

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Night Sky Camera Settings Summary

  • On DSLRs, turn off auto focus, on other cameras set it to infinity

  • Set your camera to program or manual mode

  • Set ISO to 400, 800 or 1,600 based on ambient light

  • Turn off burst modes

  • Set optical resolution to the highest setting

  • Set white balance to daylight or allow the camera to set a custom balance

  • Use a ‘raw’ file format where possible

  • Use a remote release or timer option for wobble-free photos

  • Turn off flash, red-eye and focus lights

So, wrap up warm, fill up the Thermos and get out into the countryside to see what the night sky has to offer. If you follow some of the tips above, you might find yourself with a photo of something truly spectacular, and whilst you can of course search the internet for incredibly impressive photos, there’s something special about saving your own view of a starry night sky.

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