What is Astrophotography?

Astrophotography is the process of producing photographs of objects in the universe and large areas of the sky. Mostly it is done at night but some may be done during the day i.e. of our Sun. It can be done with equipment as simple as a mobile (cell) phone to specialised equipment requiring significant financial investment. Astrophotography is easy in the beginning stages but becomes difficult at advanced levels.

With a camera with manual controls photographs of the night sky can be taken with the aid of a tripod. Keeping exposure times low enough, so that motion due to the Earth’s rotation is not significant, can lead to great photographs of the night sky. For this you need to use the camera’s timer or a remote shutter release to keep vibration to a minimum. The photo on the right was taken with this method (click for larger image).

With a small telescope and a mobile phone photos can be taken of bright objects on the sky. The Moon is a great target for this technique. With the telescope pointing at the target and the camera held to the eye-piece reasonable photos can be taken. The trick is positioning the camera correctly and it does take a bit of practice. Specialised brackets are available to hold the camera in the right position.

The next step up is to directly attach and DSLR to a telescope. In this fashion the telescope becomes the camera’s lens. With this technique more advanced image processing can be used to enhance the images. The photo on the right was taken with this method.

Dedicated cameras are available to take the place of DSLR cameras. The advantages of these are increased sensitivity (particularly in certain colour ranges) and cooling. These cameras produce colour images with low noise (due to active cooling). They do however require the use of computers to control them making the process more complex and increasing reliance on software.

The next level up is a large jump in technique and is the pinnacle of astrophotography. It involves the use of specialised cooled monochrome cameras. These cameras produce higher definition images than the previous techniques. Colour is produced from these cameras by the use of filters. In its simplest form images are taken using red, green and blue filters which are later combined in specialised software to produce a colour image is the same way as televisions do. All high end astrophotos are taken using this technique including those from the Hubble Space Telescope.