5 replies to this topic

[asee64]

Hi all,

 

..just finished my minimalistic DIY observatory - three vertically telescoping shells and a hinged roof, all driven by linear actuators and controlled by Arduino.

 

Has anyone ever used a vertical telescoping design before? I am not sure; but given the obstacles I encountered on the way such as 8 desynchronised linear actuators fighting each other I would not wonder if no-one has tried this before

 

best,

Asee

 

 

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[Phil Perry]

Neat idea. I would be a bit worried about wind loads on the big flat sides (cylindrical shells would be better), snow/ice loads on the lid, and seals around the segments to keep critters out. What safeguards do you have against the thing "deciding" to retract with the lid still closed, or jamming due to one lead screw going a bit faster than another? For that last case, I would have envisioned using all four corners driven by a single chain, so they're guaranteed to turn at exactly the same speed.

[asee64]

Hi Phil,

 

thanks for looking.

 

- yeah, I am worried about the wind, too, I will screw it to the ground (to do list), and ultimately the pier inside will keep it from flying away..

 

- snow will have to be removed manually

 

- there are no seals on purpose: the thing is quite open, to enable airflow like a chimney inside. If it will be squatted by inhabitants, I'll make a net at the bottom

 

- I integrated a lot of sensors and programmed quite a bit, and made a RS232 interface to the mount, to prevent any crashings - there are 4 moving parts: mount, lid, upper and lower shell, so this was quite a task

 

- jamming - well, that's a problem. I tried to get a synchronisation controller and linear drives with hall sensors, but could not find any at a reasonable price, so I'll just have to wait until the first drive fails...

Edited by asee64, 05 July 2025 - 09:34 PM.

[asee64]

PS:

- yes, a cylindrical design would be much prettier, but would hinder me to access the scope from both sides neatly. My first design was a slide-out lid, see pics, but that took too much space to walk around.

 

- as to the single chain:  would have been a great solution! But dealing with chains and sprockets and threaded bars and bearings is unfortunately beyond my skills; the linear drives are off-the-shelf and water-proof encapsulated and do not require greasing.

 

what I envisaged (and used for the roof drive) are pull wires, that would have been within my skills, but 4 pull wires would have required a lot of turning pulleys

 

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Edited by asee64, 06 July 2025 - 02:06 AM.

[star acres]

You need a big carpet around it for when you drop eyepieces. From that height, a thick one. 

[asee64]

it's for photographic use only

Edited by asee64, 06 July 2025 - 07:44 AM.