Motorizing the Out Haus Observatory
During the winter, more than once, I have started a session running with CCDAutoPilot, gone to bed under crystal clear skies but discovered at 2 am that the telescope was pointing to the zenith and that snow was accumulating on the mirror. Not a happy discovery. So, I would leap into some clothes, run outside where I'm greeted by 10 degree F temperatures with snow falling so hard I can hardly find the observatory and I slide the two sections together.
This year, I decided to try and avoid these joys of winter so I purchased the new portable cloud detector from Cyanogen which (I hope) will wake me when it's cloudy before the snowflakes start to fall. I also purchased a hoist from Harbor Freight Tools and installed it in the Out Haus. Here you can see the hoist mounted inside the Out Haus. It is installed on the side where the weight shaft is when parked so there is plenty of clearance. The cable runs from the hoist's spool to the lower left in the photo toward the Out Haus half that is on that side. You can also see it returning above the hoist and past the pier base on its way to the other side.
The photo below shows the pulley and hoist cable on the counterweight side. The cable simply runs from the hoist, through the pulley and returns back over the hoist.
Next you can see the opposite Out Haus half where the cable has passed beside the pier to a second pulley in this side. After passing thru the pulley, the cable returns towards the pier where it is attached to a spring. The spring is then anchored to the Out Haus tracks. The hoist is rated at 440 lbs so without the spring, the Out Haus halves would be torn to pieces once they reach the center and contact each other. The spring prevents damage from occuring.
In operation, when the hoist is turned on and retrieving cable, one Out Haus half or the other will begin to slide on the track. In the photo below, you can see a 1/2" lag screw inserted in the track which stops the Out Haus halves from moving. Once one of them gets there, it will stop and then the other side will begin to slide along the track. When they reach the closed position, the spring will begin to be stretched by the hoist allowing me a little time to let go of the button on the controller.
Lastly we see the hand controller for the hoist.Normally I leave it outside on the porch so it is sealed up in a plastic bag but the cable can be laid through the front door and still allow the door to close. This way I can use it from inside the house when closing the observatory or I can walk out to the observatory with the controller in my hand. This is necessary because when opening the Out Haus, I have to run the hoist in reverse and slide the halves apart by hand. The original cable for the controller was only 6' long so I had to replace it with 100' of 4-conductor cable, this was the only modification to the system. The black button in the bag is a rocker switch that runs the hoist in either direction.
Harbor Freight now sells a winch that would be a better choice for this use, it runs in both directions but uses 12 VDC which I have a strong preference for (everything except thge hoist in my observatory runs off a 12 Volt deep cycle battery so I can keep going in the event of power outages). It also has a wireless controller which would make for easier operation.
See a video of the Out Haus in operation!