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FrancoRodriguez
03-08-2020, 08:24 PM
Hello everyone. I'm building a new roll off roof obsy. I am very lucky because one neighbour has a bobcat and the other is a builder who will be doing most of the hard work and technical designs.
I'm going to add to this thread as the process unfolds in the next couple of months. The bobcat and digger are coming on Wednesday.
The location is on the Darling Downs in QLD, about 1/2 hour south of Toowoomba. I live on 5 acres with no street lights. Bortle 3-4.
It will be a 3.5 x 4m roll off roof gable obsy, around 2m tall, with a 4x4m outdoor platform for viewing. It will have a 2 x 1.2m deep concrete footings, independent of the flooring to reduce vibrations. I will only be using one pier for now but I'm thinking about the future. I may want to have 2 telescopes going at the same time.
The main structural strength will come from a set of 2 very heavy rails which I got from Admerch. I got 4 solid brass track wheels, each one able to take 1500kg of force in every direction (most bearing systems are only designed for downwards gravitational force, but these ones can resist a lot of wind, in particular lift from updrafts).
I am totally new to this, and so is the builder (but he is extremely clever and and very well known in our region). I hope that anyone who is planning on going down the same path as I sees and learns from my mistakes and successes (I'm sure there will be plenty of both!)
I am so excited, a little scared, but I know this will be one of the best things I've ever decided to do. :eyepop:
Wish me luck!
See photos attached of the site. It will be in the old fenced area
https://imgur.com/a/ep9HaLv

FrancoRodriguez
03-08-2020, 09:35 PM
These are the wheels
https://admerch.com.au/product/gtr028-5-wheel-cantilever-gate-wheel-set/

And the rails
https://admerch.com.au/product/cantilever-gate-channel-heavy-series/

Joshua Bunn
03-08-2020, 10:57 PM
Good luck Franco. It sure is an exciting journey. I'm sure you will do great.

Sunfish
04-08-2020, 08:28 AM
Good luck and happy building. Those wheels and track look to be incredibly heavy duty.

FrancoRodriguez
08-08-2020, 12:48 PM
Well, after much work with a bobcat and auger the base of the pier along with 9 footings, all over 1m deep into the ground has been sunk. There will be plenty more concrete to come. The concrete that was used was 32MPa. The plinth for the pier will be 1200mm deep and 600mm diameter, reinforced with L shaped rebar. The tall poles, 100mm steel square beams will be cut to size.
I decided on just one pier. I could have gone for two but this would have caused issues with the minimum angles to the horizon, and possible clashing if I ever get a really long scope.

https://imgur.com/a/E8H9qwY

FrancoRodriguez
08-08-2020, 01:47 PM
I'm trying to get the photos under 200k so they can be seen on IIS

FrancoRodriguez
03-10-2020, 03:33 PM
So, the roll off roof observatory is finally coming together! It's got a 600mm diameter pier, 1.5m underground plinth with buttress rebar steel, completely isolated from the floor. The obsy will be 3.5 x 4m with roll off roof, and an outdoor balcony for visual astronomy. Can't wait till it's finished! If anyone wants the name of the builder he's a bloody legend. Cameron "Hambo" Hamblin in Ramsay just south of Toowoomba https://imgur.com/a/E9vrNo2

Anth10
06-10-2020, 05:06 PM
Lookin good Franco- very sure footings I see- it’ll hold you in good stead.
Keep it up .

Anth

FrancoRodriguez
06-10-2020, 10:05 PM
Thanks Anth! Yes, it's way over-engineered. Far more than I had anticipated. Better over than under I suppose. The steel is really heavy and thick. I don't think it'll have much bend in it at all. And the concrete goes over 1m into the ground. I couldn't resist the urge to add a few glow in the dark rocks to the concrete mixture. They glow blue. They're very sparsely distributed. Probably a little tacky, but kids will like them and they won't interfere with AP or viewing.

FrancoRodriguez
20-12-2020, 05:49 PM
fter well over a year of planning, and a lot of help, my observatory is finally finished! Can't wait for these damned clouds to pass so I can get first light! I'm over the moon...but I want a bigger telescope of coursehttps://imgur.com/a/vKGCEPT