Hi Group,
Firstly I would like to thank Jeff Latsch in another post for planting the conversion seed. I said and I quote
"Just to add I would not consider converting my mount unless it was broken" well it wasn't broken and convert it is exactly what i have done.
As my mount was still working I wanted to complete the conversion without chopping anything off so I could replace the stock system if I needed to. I have used Nema 17 17HM19-2004S 2A 400 step motors with 12T-60T and 158mm GT2 belts giving 5-1 reduction.
I started by machining the centre hole in the original motor mount bracket to allow the 12T pulley to fit. I then made and anodised in "Celestron orange" 2 motor mounts that adapt the Nema 17 bolt pattern to the 3 hole stock motor pattern. The belts are tensioned via these 3 nuts.
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I have also used the CGE Pro PEC/home and limit switches.I made new slave pcb's to go inside the motor covers to attach the switches and motors. The RA housing needed 9 terminals and the Dec needed 6 so new drive cables were made.
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The motors fit perfectly inside the covers
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I used a modified MiniPCB2 with Teensy 4.0, I added a small slave pcb to the teensy to pinout for the home switches and GPS. I soldered jumper wires to the slave pcb from the pads on the underside of the Teensy 4.0 using Pins 24/25 for GPS, 26/27 for home switches and 35 for PPS from the GPS module. I kept limit switch on the same pcb pin but modified the pinmap.
The case was also anodised in "Celestron Orange"
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First Light 31.7.20
The scope is a 14" EdgeHD with a 0.7 reducer so 2737mm focal length, Guiding via OAG and PHD2
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With such a long focal length I was expecting some huge teething problems so I switched everything on, clicked find home which worked perfectly then took a 10 second image at NCP. Oh no star trails! but worse than if tracking was switched off so I knew the RA motor direction was wrong. I reflashed the Config.h and took another image, perfect this time. I plate solved and slewed to the Bubble Nebular, it was not far off but another plate solve got it spot on.
Now have a look at this for a first image, its just a single 5 min Hydrogen Alpha sub but its unguided!! It wouldn't do a 2 min unguided sub with the stock setup.
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With guiding on and no changes made from celestron motor setup, I'm sure I can dial this in further.
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Just before the clouds rolled in I got a couple of guided 10 min pics of the centre of the Pacman nebular.
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I am blown away by the out of the box performance of OnStep, many thanks to all involved. I will post an update when I get some clear skies.
Thanks for your time
Curly
