Jessie Ray – October 2024

THE REASON:

My trusty Celestron CG5 Advanced GT mount has been… not to trusty since it came back from being repaired by Celestron. I had sent it to them to be fixed due to the motor control board dying and they insisted that the motors needed to be replaced as well. All told that costed me almost $500 USD in August of last year not including the shipping cost to get it from Virginia to California. Am I stupid? There is a good chance that might be the case since I could have bought another one for less than that. Or I could have done what I have decided to do now, which is convert it to OnStep. Recently the motor control board that was installed by Celestron has taken to randomly disconnecting during a slew and will not continue unless you hit the back button on the hand controller. Wouldn’t be a huge deal for visual use since I would already have the controller in hand, but I use this mount for astrophotography (I use an 8” dob for visual) so I am usually asleep when this thing is doing its job.

Mechanically there is nothing wrong with the mount, and the more research I do online the more I find that I think I will be perfectly happy with it after I replace the electronics, and while I am at it I may as well convert it to a belt driven system to increase the accuracy.

I have not started on this, so everything below this line of text is based solely on my preliminary research. Come back to my site later to see the progress as I work on it. In the meantime, I will try to continue my imaging projects with my small Explore Scientific iExos 100-2 mount, but I’m not sure I will even be able to get my 130mm f/5 Newtonian to balance on it so it will probably be wide field projects with a DSLR and lens for a while.

THE REQUIREMENTS:

• An Arduino
  • This is what will run the OnStep firmware and interact with the motors
• 2 Nema 17 motor and drivers
  • One motor each for the Dec and RA axis
• 2 belts and pulleys
  • I will be converting this to a belt driven system, so I will need belts and pulleys to run from the motors to the gearing on the mount
• Cables
  • I will need cabling to hook everything together
• A covering
  • This is technically optional, but I would just feel better if all of my electronics are nicely contained in some kind of box. The main thing that really needs to get covered is the Arduino, but I would prefer it if the motors and the gearing were covered and not exposed.

The next post I make about this should include the parts I purchase and any math I have to do to figure that out. I am still in the beginning stages of this, but I don’t think there is any reason to get rid of something that is mechanically sound if I can bring new life into it.