Which motor for sliding roof obsy?

[Jannerland]

Having finished most of the construction of a micro observatory along the lines of New Sliding Roof Mini Garden Observatory Build - DIY Observatories - Stargazers Lounge which inspired mine I'm pondering automation of the roof.

I'd like to ultimately be able to integrate the open close into an imaging session with weather (rain)  checks and will need to be able to get the scope into is custom park position before closing.

I've browsed through a few other threads using sliding gate motors but I'm struggling to find ones that other have used being available. I'm not sure if the above requirements put constraints on which one I go for?

Appreciate any thoughts..

 

 

[Tomatobro]

Finding out how to get  two independent systems to operate together is the first step. Closing a roof with a rain sensor is straight forward and parking a scope at the end of an imaging session can be done in Sharpcap and NINA software. What you need to establish is that a rain sensor signal can close the imaging session, park the mount and then (and only when) parked close the roof.  Light beam sensors can be added to detect a potential collision between the scope and roof.

I am sure this has been done and hopefully somebody will post a method that works. For me though I would need to be absolutely sure that I know how to do this and its within my capabilities before going any further

[AMcD]

For my ROR observatory I have used the Talon roof system, integrated with the Lunatico Cloudwatcher AAG and the Lunatico Dragonfly relay box to ensure that the system responds to the weather and ensures the telescope is out of harms way when the roof closes.  It has worked flawlessly so far and will sometimes open and close the roof multiple times during an imaging session if the night is one with only intermittent clear periods.  The system also allows me to control the observatory online so it can be used from the house, or indeed anywhere in the world.

The major drawback of this route however, is the cost.   The Talon, Cloudwatcher and Dragonfly, together with the associated power transformers, cabling, ethernet hub, UPS power supplies (to allow the roof to close in the event of a powercut) and server cabinet were rather expensive.  As was the Starlight Xpress All Sky Camera that allows remote confirmation of the imaging conditions.  That said, it has allowed me to go from using my observatory perhaps four of five times a year to using it four of five times a month depending on the weather.  Pictures of the set up below.

 

[ncjunk]

I used a gate motor for my roof which came with, obviously, the rails for moving the load (in this case roof) and a control board which had some useful interlocks on it 

On mine I left it open all night (so only clear nights) but you could disable it by using a safety input based on the position of the telescope. The safety would be "ok" when the scope is parked - this should be a hard wired couple of switches which are active when the scope is parked.

Your case isn't ideal as the telescope must be in parked position for the roof to close. there will be the possibility of the roof closing on an unparked telescope if you don't disable the motor when the telescope is unparked. The only surefire way of safely doing this is physical limit switches detecting when in safe position. If the park position is taken from software and not the physical position you will always have the possibility of damaging the scope as software is not reliable.

Having said all of that the opening and closing is easy and just done on wired signals. If you have programing knowledge you can program an arduino with a couple of Inputs and outputs and then link it to an ascom driver (I'm sure someone will have done one somewhere)

I'd start off with a gate motor hooked up to an arduino that has wifi and create a mini webserver with buttons to open and close the roof, just open, close and then an indication of current position.

This way is cheap but needs a bit of programming knowledge and also some wiring knowledge for the connections and the signals to the park position.

So, a control just to open and close manually is easy. The hard bit would be the ascom driver interface with the arduino and the wiring of the limit switches showing park......and then the intergartion and testing with your existing softare.

Sorry for the brief explanation if a diy solution..hope it gives you an idea.

 

This is a classic example of if you have the money and not the diy skill go for the Talon system mentioned by a previous poster but if you have the skills and fancy a challenge you can do the cheap diy method

Edited September 14, 2022 by ncjunk
typos and sentence on Talon or diy

[Carbon Brush]

I used a garage up/over door automation package. Intended for after market fitting.

The motor sits inside the end of the shed. The rail runs along the 'pergola' constructed to hold the roof when open.
The hook to catch the door is fastened to the end of the roof.

This package includes motor overload detection (person or car in way) and reverse.
The radio remote is very handy when investigating travel stickiness caused by plants growing, wood warping, etc.

I have made no attempt to trigger closure on rain, etc. or after scope parking.
The controls include terminals for a push button closure.
Though most packages are push to close, push again to open. not separate switches.

They don't generally use limit switches as standard. Relying on simple encoders in the motor drive.
I have a 'roof fully closed' limit switch which is tied in with the shed alarm. Signals if anyone succeeds in moving the roof an inch or two.

Hope something in there is useful.

David.

[AMcD]

21 minutes ago, ncjunk said:

This is a classic example of if you have the money and not the diy skill go for the Talon system mentioned by a previous poster but if you have the skills and fancy a challenge you can do the cheap diy method

Just to say that the Talon etc. does require a degree of DIY in that it required me to adapt Talon system, rack etc. to my particular ROR observatory, which in turn required some re-engineering of the observatory rood before I installed it.  It also requires building and wiring up the server cabinet / to all of the individual components of the system, mount, camera etc. in the observatory.  I think in total it took me about two weeks of working every day to get it installed and up and running😃  This post records the process: 

 

[ncjunk]

2 hours ago, AMcD said:

Just to say that the Talon etc. does require a degree of DIY in that it required me to adapt Talon system, rack etc. to my particular ROR observatory, which in turn required some re-engineering of the observatory rood before I installed it.  It also requires building and wiring up the server cabinet / to all of the individual components of the system, mount, camera etc. in the observatory.  I think in total it took me about two weeks of working every day to get it installed and up and running😃  This post records the process: 

 

Well said, it's still work but you don't have to write your own software as it comes with ascome drivers, software etc, if i remember correctly.

...and you have a post explaining it! what could go wrong😁

 

[AMcD]

1 hour ago, ncjunk said:

you don't have to write your own software as it comes with ascome drivers, software etc

Indeed!  I have always wanted to learn Python, but I suspect this old dog is too old to learn that new trick 😃

[ncjunk]

4 hours ago, Carbon Brush said:

I used a garage up/over door automation package. Intended for after market fitting.

The motor sits inside the end of the shed. The rail runs along the 'pergola' constructed to hold the roof when open.
The hook to catch the door is fastened to the end of the roof.

This package includes motor overload detection (person or car in way) and reverse.
The radio remote is very handy when investigating travel stickiness caused by plants growing, wood warping, etc.

I have made no attempt to trigger closure on rain, etc. or after scope parking.
The controls include terminals for a push button closure.
Though most packages are push to close, push again to open. not separate switches.

They don't generally use limit switches as standard. Relying on simple encoders in the motor drive.
I have a 'roof fully closed' limit switch which is tied in with the shed alarm. Signals if anyone succeeds in moving the roof an inch or two.

Hope something in there is useful.

David.

The sliding gate motor I had has a metal bar which is attached to the end of the rail and as it moves past the motor it hits a switch stopping it.

I used the remote controls that came with it to open and close it from the house and had a wifi camera I logged into to check the telescope had parked.

I'm thinking of trying a garage door style one next.... I'm not sure though.

[ncjunk]

If you look at Glenblokes thread and the Motorized ROR video this is exactly the type of setup I have and i used the remote controls that came with it.

https://stargazerslounge.com/topic/387345-my-complete-fully-automated-diy-ror-shed-observatory/

[Jannerland]

Thanks everyone for the insights and experience - much appreciated! 

[Jannerland]

@AMcD Quick question on the physical dimensions of the Talon system  - can you give me some idea how much space is taken up by the mounted motor as shown in the image you shared?

Just trying to figure if it would even fit in the space i have. If not I can eliminate from my lingering thoughts 🙂

[AMcD]

1 hour ago, Jannerland said:

@AMcD Quick question on the physical dimensions of the Talon system  - can you give me some idea how much space is taken up by the mounted motor as shown in the image you shared?

Just trying to figure if it would even fit in the space i have. If not I can eliminate from my lingering thoughts 🙂

@Jannerland The motor assembly is pretty compact.  I have marked the dimensions of the area occupied by the motor with mount and pinion on the photo below.  The box with the electronics is likewise modest, with dimensions in cm of width 24, height 19 and depth 9.  Hope this helps.