Add a spotting scope to your Astra V2.1 barn door tracker.

THIS DID NOT WORK! See the later blog entry.

Note This is a work in progress, I need to verify that the setup and use works well the next clear night

While you can do pretty well aligning the tracker with an iPhone’s compass and bubble level, it would work out better to use a spotting scope to line it up with the North star.

What I’ve done is bought this red dot finding scope from Amazon — note if you buy from the links on this page I’ll earn a little bit.

Red Dot Finder Scope
And a supply of M4 screws nuts washers — you’ll need two 20mm ones

I’ve used it and it’s easy to set up and use. And you might think a whole box of M4 screws is over kill but this is a great size for all kinds of projects including building the tracker itself

So what I did was create a clip that attaches to the tracker to hold the finder scope, but also a clip that fits on the shoe of my DSLR camera.

Why both? Because the finder scope needs alignment and so if I only attach it to the tracker I’d have some complex iterative process where I align the tracker by iPhone, then turn the dials on the spotter until the dot lines up with the north star, then test shoot to see if I get trails, and repeat the process until it’s perfect.

Instead I use the shoe mount and the spotter on the camera, easily turn the dials to align the spotter to the camera (pick a bright star or planet and make it go inside the central auto-focus spot square, and align the scope), now since the bracket is square to the tracker, moving the spotter to the tracker mount should now have it aligned to the axis of the tracker.

Hey… now you can set up you tracker on a tripod, put the spotter on it, line it up with the north star, place your camera on the tracker, re-check and adjust the tracker aim, and now move the spotter to the camera. Turn on the tracker. Now you can use the spotter to help aim the camera to the desired star or area of the sky.

Here is a link to my Thingiverse page for the two 3D models you’ll need to print. for both of them, print them standing on end and you wont need supports. I did not need brim, as PLA sticks real well, sometimes too well, to my build plate.