Astronomy

I am an amateur astronomer and astrophotographer. I post some of my results here. All images are made available under a CC BY-NC-SA license. If you want to be notified about new astrophotos, you can subscribe to my Atom feed.

How do you take these pictures?

The short answer: clear skies, lots of patience/long nights and expensive equipment. You can probably guess that a telescope is involved, but astrophotography requires a lot more equipment. The two main problems with photographing deep sky objects is that from our point of view they are very small and very dim. For visual observation you need a larger telescope to gather more light. When you're taking pictures, you can take long exposures instead. However, the Earth's rotation means that the stars move over the course of the night and long exposures result in trailed stars. But if you rotate your telescope (using what is called an equatorial mount), you can cancel out the Earth's rotation. However, even a five minute exposure usually looks pretty noisy. So, you take a lot of them and overlay them: stars and deep sky objects remain similar between exposures, but noise changes and averages out. I try to get at least one hour of data on any object, but especially for fainter objects I'll sometimes go for upwards of ten hours. Professional observatories may even combine hundreds of hours of data into one picture.

Bode's Galaxy and Cigar Galaxy (M81 and M82)