Astrophotography is photographing objects in the night sky such as the moon, the planets, constellations etc. These objects are pretty dim, except for the moon. This presents certain challenges and therein lies the fun. Advanced amateurs often use digital cameras with manual settings to overcome these challenges. Here I am going to talk about beginners who have only a decent mobile camera to work with. I assume a minimum of 32 megapixel camera with an app allowing for manual settings for exposure, ISO, etc. And yes, this piece is for the completely uninitiated, hence the simple language.
The challenges with a mobile camera
upon which light is not being received, are given artificial signal to look illuminated
. In simple terms, you are creating a bigger picture by simply smearing the colors of a small part, all around. This is done with a lot of sophistication and yet, it is not the real picture. So for tiny objects, this will only blur the object.
- The background is often too bright. The mobile cameras using software automatically try to raise the brightness of the picture. The sky (dark to the eyes) is thus enhanced so that tiny fragments of light are inserted into each sensor to make the photo brighter. So if there is say one unit of light falling on the dark areas while about 100 units on the area illuminated by the object, the software upgrades these numbers to say, 5 and a 105. Thus the sky appears bright, and the object becomes over-exposed making it to lose its detail.
So how to overcome these problems
- Use a tripod or firm support for your hands
- Use a camera app or a mobile phone which allows you to set manual settings for ISO and exposure.
, the moon would need about 1/100 sec for the same ISO. Jupiter would need something like 1/10 second to be barely visible. Stars even longer, like 5-10 seconds or more. Galaxies using professional cameras would need around 5-10 minutes on a regular ISO.
You surely get by now that just these two settings - ISO and exposure - can bring about great results. And it is all about mixing the values of each and trying out various combinations until you become good at it.
The idea is NOT to get a good looking picture, but rather an informative one.
And if you really need just an artistic capture, try playing these numbers and see if you can get something like this last picture here. Happy Astronomy and Astrophotography to you all.