Andromeda Galaxy II

Andromeda galaxy with barn door tracker

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.

Details: Nikon D7000Nikkor 180mm f2.8 at f2.8. 64 minutes (48 x 80 seconds) at iso 800. Using didymium filter. Stacked with Deep Sky Stacker and tracked with barn door tracker.

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).

andromeda galaxy exposure length


  1. Jim Gage Reply

    Nick, I have just discovered your site, and had to say how impressed I am by your images. I tried out my barn door drive tonight and fizzled… then I came home and searched until I found yours. I have to say, I did not know images like these were even possible with one! I am processing pictures from our astronomy club’s 16 inch, and they are not nearly as fun as these 😛
    Thanks for taking the time to post all this info. Keep it up!

    • Nick Reply

      Hi Jim – thanks for the kind words!

      In answer to your question, the timing between beeps for the 6mm version of the tracker is exactly 4.2 seconds. But I have to confess, I don’t actually have an equation for the timings. Instead I used good old fashioned trial and error, adjusting the beeps until the tracking was spot on.

      Hope that helps – good luck with the tracker build!


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