After being blown away by my first attempt at the Andromeda Galaxy, I couldn’t help having another go with the improved barn door tracker, this time using longer exposures of 80 seconds, and a lower iso of 800. The resulting image has a lot more detail and much less noise than the original, despite being taken from the back garden with plenty of light pollution and a rising moon. Click here to view the image at 100% scale.
Having experimented with different ISO speeds on the Nikon D7000, I’d say that iso 800-1000 offers the best balance between noise and sensitivity for astrophotography.
Below is a side-by-side comparison between the original image (5 x 30 seconds at iso 1600) and a recent image (18 x 80 seconds at iso 800).