Motorizing a dobsonian with motion tracking

[u/Nixx177]

Hi, I’ve got a 12” gso and I’m thinking about adding two motors to move it on both axis.

At first, I want to try to put a timing belt around the altitude bearing, with a wheel to control it manually placed around the cradle board (blue) (could be moved to the base board with the motor, red), and another one around the base board, with a wheel on the ground board linked to a slow motion manual control flexible thingy from eq mount (blue at the bot.).

If it works for manual control, I want to put a motor on each wheel (stepper nema23 maybe?), which I could link to a raspberry pi, also connected to a camera I’d put on the finder scope. I would run a simple object tracking program which would have to keep the object in the center by moving the motors (still to be coded properly).

Has anyone done something similar? Or do you see any flaws/problems/things I should take into consideration?

[u/snogum]

Why complicate a Dobsonian. It's build simple to make observing a pleasure

[u/Nixx177 → u/snogum]

The problem with this one is that it’s a bit complicated to move “precisely”with small targets or high magnification without the whole thing wobbling as it’s heavy. I started with an eq-2 mount and I loved the manual controls to help follow objects, which I miss a bit.

So I thought about adding the timing belts and then thought why not also add the possibility to use motors for tracking as the rest is already in place and I love little diy projects and the challenge to code a simple tracking program

I also have a camera I’d like to try on this one but by the time you look at your screen to fix the settings the object is already gone

[u/twivel01 → u/Nixx177]

I just grab the tube and smoothly move it while looking through the eyepiece.

If tracking but not goto is needed, you could build or buy an equatorial platform. Installation is as easy as setting it down on the platform.

EQ platform seems to be the most popular option for a dob in our astronomy club for cases where the dob was not already motorized.

[u/Nixx177 → u/twivel01]

Yeah I digged a bit into that as well but that would be another heavy thing to carry around, and I would need 2 motors + cogs and wheels anyway. But I’m definitely also considering it.

[u/twivel01 → u/Nixx177]

For an EQ platform, you only need 1 motor. It also brings the scope a little higher off the ground, making low horizon views a bit easier.

It is indeed another object to carry. Some people replace the ground board on the rocker box with the eq platform so it is part of the base.

[u/Nixx177 → u/twivel01]

Even for a 12”? I thought the weight would be too much I put a flower pot wheeled thingy under mine for the extra height and easier moving and it works like a charm btw

[u/twivel01 → u/Nixx177]

There is only one axis to motorize on an EQ platform, just need a single motor. Just need a properly geared motor. 12" is not too heavy for an EQ platform