Original heq5 conversion #mount #onstepx #skywatcher


mitchellcram@...
 

Hi all,

I have just discovered the onstep project and have been reading up on how to put it together. I have the opportunity to purchase an old original non Goto black heq5 mount and thought it might be a good candidate for converting.

I already have an heq5 from new and have the Rowan belt mod on it, and use it exclusively for astrophotography. I'd love a second one though to run two setups, so very interested in all this.

I was wondering if anyone had any experience in converting one of these mounts? Obviously the original motors in the mount would not be very useful for slewing, and I think I have found a suitable replacement in the form of these nema 14 motors (https://www.omc-stepperonline.com/nema-14-bipolar-1-8deg-18ncm-25-5oz-in-0-8a-5-4v-35x35x34mm-4-wires-14hs13-0804s), however I'm having trouble getting my head around how to convert this to a belt drive, or if it would be ok to just use the existing gears (this mount has only 2 large gears rather than the 3 of the newer mounts). 

Basically I'm just looking for a bit of guidance. I can assemble the onstep hardware no problems and should be able to work my way through the software side, it's more just making sure it's worth replacing the motors and possibly the gears. 

I have a friend who will soon be selling a modern belt modded heq5 that would realistically only cost me a couple of hundred dollars more than this project wil cost all up, so would this even be worth it or should I just hold out for the more modern mount?

Thanks in advance for any possible help 🙂


Howard Dutton
 

On Tue, Jul 26, 2022 at 03:55 AM, <mitchellcram@...> wrote:
I was wondering if anyone had any experience in converting one of these mounts? Obviously the original motors in the mount would not be very useful for slewing, and I think I have found a suitable replacement in the form of these nema 14 motors (https://www.omc-stepperonline.com/nema-14-bipolar-1-8deg-18ncm-25-5oz-in-0-8a-5-4v-35x35x34mm-4-wires-14hs13-0804s), however I'm having trouble getting my head around how to convert this to a belt drive, or if it would be ok to just use the existing gears (this mount has only 2 large gears rather than the 3 of the newer mounts). 
I know little specifically about these mounts but generally if using the NEMA14 motors mentioned and having 135 tooth wheel gears I'd guess you would want another reduction of about 6:1 or 7:1 in there somewhere.

Basically I'm just looking for a bit of guidance. I can assemble the onstep hardware no problems and should be able to work my way through the software side, it's more just making sure it's worth replacing the motors and possibly the gears. 

I have a friend who will soon be selling a modern belt modded heq5 that would realistically only cost me a couple of hundred dollars more than this project wil cost all up, so would this even be worth it or should I just hold out for the more modern mount?
Can't answer that one, depends on the person and abilities/desires.  That said if it were me I'd rather have mounts running the same control system and that would weigh into it.