This was my first attempt at imaging a DSO (Deep Sky Object, meaning anything that's outside our solar system). It's not a fantastic image, but my excitement when I saw the first shots appearing on my screen, confirming that I had managed to make my new telescope point accurately at an object that's invisible to the naked eye and appears to move across the sky because of the Earth's rotation about its polar axis, was enormous. I was grinning like a small child on Christmas morning.

I had only recently treated myself to not only a full new telescope package, but also a new camera, and this was my first opportunity to make an attempt at taking the kind of image I had been viewing enviously for a long time on several astronomy websites.

I don't really remember if there was any specific reason for me choosing this particular target as my first attempt with the new equipment. I suspect I probably tried for some time to get something in the frame with lots of test shots, and this was the first object that gave me the feeling that I could make a nice image of it.

The object pictured here is known by several different names, including The Pinwheel Galaxy, Messier 101 and NGC5457. It is a spiral galaxy in the constellation Ursa Major (The Great Bear), which includes the widely recognised asterism of The Plough, or The Big Dipper. Lots of further information about this object can be found on its Wikipedia page.

The most challenging aspect of capturing this image was probably the learning curve involved in figuring out how to make use of a wedge to turn a mount primarily designed for visual use into one capable of long exposure photography. The Celestron Nexstar Evolution is what is known as an Alt-Az mount, which means that it moves in an easy to understand left / right / up / down manner. This makes it easy to use for beginners, but it's not the right kind of movement for tracking objects as they move across the sky. The addition of a wedge tilts the entire mount such that the axis of rotation that was set up for left and right (or East and West) movement becomes aligned with the Earth's axis of rotation. Without the use of the wedge, the mount can still track the object across the sky, but since objects move in arcs across the sky for most Earth bound observers (unless you're standing exactly on either the North or South pole) then the mount has to move in both of its axes to track. This causes a phenomenon known as field rotation, meaning that the image slowly rotates about the centre of the camera frame over the duration of image capture, possibly even within each individual exposure.

You can view this image in the WorldWideTelescope by clicking here.