The Night Sky
An interest in photographing the night sky lately has had me out in the dead of night trying different techniques for capturing the stars. From long exposures to catch the movement of the planet to image stacking techniques to bring out the colours of the cosmos, it has been an interesting learning curve.
There are two different ways to achieve this – one is long exposures, setting the camera in Bulb & leaving the shutter open for a pre-determined amount of time as in the image above. The second method is to take a series of short exposures & use a program such as StarStax to combine them into one image. A remote shutter control & a tripod are needed to eliminate camera movement.
The Milky Way
As the planet rotates, taking photos of the Milky Way can be a little tricky, You will be surprised at how far the planet rotates in just five minutes. Faster shutter times will be needed to keep the stars a sharp points. Higher ISO`s will help but the higher the ISO the more noise will be introduced.
A rule of thumb when taking these images is the Rule of Ten. To keep the stars sharp, divide your focal length by 10 to give you an exposure time. If you are using a 50 mm lens, a 5 second exposure will keep the stars sharp.
The image below is a 10 second exposure at f4 & 1600 ISO. Not very spectacular right?
But when 20 images stacked together using a program such as DeepSkyStacker are put together some interesting results can be achieved.
The aim of using stacking is to reduce the Image to Noise ratio by using “Dark Frames” in the stack which take out the noisy pixels. DeepSkyStacker does take some time to get the hang of but the results are worth it.
Capturing the whole Milky Way in one image can be difficult unless using a Fisheye lens. One way to get an image is to use an Compositing program. The image below is a 24 image composite, 3 rows of 8 photo`s combined to give a 180 degree view, left to right & top to bottom & was taken with a 1/4 moon lighting up the ground
The program I used for the above composite was Microsoft ICE. This program has some interesting features, it can produce Panorama`s from video footage as well as still images.
I`m still pretty new to this type of photography & I am still learning the processes involved. It has given me a new view on the night sky & something to do at night while on camping trips.