Notes From a Maker

So after two runs outside, I found a couple of places where the tracker could be improved. I will detail the issues and solutions from my experience, as well as the final results. Click here for the original build log.  Polar Alignment The most noticeable issue I had was with aligning the tracker to the pole. If the hinge wasn't pointed exactly at the pole, I got a lot of trailing and loss of tracking after an hour or so. It was actually bad enough that the stacking software did not recognize any stars in any of the images. Yeah, those stars don't cut it This issue is due to user error, and with enough training and practice, I am sure it can be done reliably and accurately. However, I wanted to make my life a little easier and make setup faster, so I needed a way to point the tracker towards Polaris with good repeatability. To do this, I salvaged a cheap spotting scope from a $20 telescope, and attached it to the hinge. After zeroing it, it made the alignment process far easier...

The tracker, with a Nikon D3100 mounted to it If you've ever tried taking pictures of the stars with a camera, you'll quickly notice two issues. One, it's really dark and it's almost impossible to see anything without a long exposure. And two, once you do a long exposure, the stars start smearing into little lines. So why do you get these trails? Well, the Earth is actually spinning on its axis, and the trails you see is actually the Earth's rotation. The stars haven't moved, but the Earth, and by extension the camera, has, and gives you that motion blur.  Those stars should be round! So how do you fix this? You can simply spin the camera at the same speed as the Earth's rotation, cancelling out the spin. Now you can buy a tracker for well over $300, or you can build your own with some simple parts for $50, or less if you have some of the hardware components, which are very commonplace. There are several designs out there, and I chose to make the curved rod ...