DIY EQ Platform for 16'' GSO Dob (+lower assembly rebuild and other mods)

[FrankRyanJr]

Taking inspiration from the 10'' platform John (westmarch) here on SGL built : https://stargazerslounge.com/topic/315290-10”-equatorial-platform-for-dummies/
plus, a lot of procrastinating and reading every scrap of info online about EQ Platforms, with blissful ignorance I went for it.
I settled on Reiner Vogel’s design for a Vertical North Segment platform http://www.reinervogel.net/index_e.html  because his designs are proven for large dobs.

This V1 is 99% finished, I just need to paint it black. It provides around 40min tracking powered by 2 x Celestron EQ drives. A fair bit of testing was done to match rotation speeds but got there in the end.
As a V2 I'll power both from a single 12V source (stepped down) and add a single power switch. 
I'm also thinking of a lever/clutch mechanism would be useful as the full set up riding on top is +55Kg so a bit of effort is required to (carefully) slide it back to start position.
At the moment I'm relying on 2 bolts as a critical stop when the end of the travel is reached on the arcs but I don't like this so I'll probably connect some kind of audio/visual warning a few min before that point.

 

Last year I rebuilt the lower assembly in 18mm marine ply. The original is particleboard which is super heavy and like a sponge in this climate.
While remaking it, I figured I could make it easier to transport and assemble by detaching the rocker from the base and making the 3 sides foldable. 
(actually just 2 sides fold and the 3rd clips in with latches).  The sides then sit down in between timber slats I attached. This all ended up making the lower assembly lighter and just as sturdy as before.

While I was under the hood so to speak, I replaced the OEM mirror springs with slightly stiffer ones and also the secondary mirror colimitation 'Phillips head' type screws to thumbscrews, all from Bobs Knobs. 
I stuck a resistor also under the glass for the Tetrad as I found this was fogging up constantly. 
Lastly, I picked up a very nifty 'Push-To' kit from Romer Optics (called EZ Push-to) for around 100 Quid and it works a treat. 

For the platform, it's a pretty small list of items really. 
Some 5mm aluminum pieces for the arcs / L-brackets. The EQ Drives - (I reckon anything under 16'' you'd just need one drive as it'd give enough torque on it's own)  
A pair of 5mm to 8mm flexi shaft couplers. A length of 8mm steel bar, 4 8mm pillow bearings. 
One fairly long M20 bolt for the Southern Pivot and 3 large bolts for the levelling feet. Then a pick-n-mix of various screws/nuts and bolts. 
 

I've logged the photos of the steps in an album here: https://www.flickr.com/photos/franks_astrophotography/albums/72157719520338922

 

 

 

 

 

 

[fwm891]

Great build - Mine is similar for a 10" dob. To be upgraded for a 16" build currently under way.