Introduction: My Observatory
I have a health problem which stops me from using a telescope in a normal way, so I wanted to use video and CCD cameras on my telescopes - remote controlled back to my bedroom. However the telescope had to be permanently set up as I wasn't able to set it up each night. Secondly there was nowhere but the front lawn or the roof to see the sky.
My mate and I chose the roof (He did all the heavy lifting for me).
Step 1: Installing the Pier
The only available place is the roof, but this vibrates if we are using the evaporative air conditioners so my mate and I decided to install a pedestal – a 14 Metres (46') long steam pipe, 1.5 Metres (5') into the ground with concrete adherent paint and reinforcing bars into one cubic metre of concrete.
The top of the pedestal has a 300×250×10mm (12×10×½") metal plate welded to it. This had four 10mm (½") stainless steel bolts to a second identical metal plate, which allowed fine adjustment of levelling. Mounted on top of the top plate was the round adapter which fitted to the Celestron CGEM-DX telescope mount.
We had installed a removable 'Crane' made of a 4×4 reversible winch and water pipe to lift my mount and telescope up to the top deck, and we used this the lift the pipe into a vertical position. Many helpers and lots of sweat from mates and my sons in-law made the jobs work.
We (they) dug a 1.6m (6') hole and concreted in the pipe, making sure it was vertical, and had the top plates facing true south, then locked it into place with timber at the top so that it wouldn’t move while the concrete dried. This worked quite well, very little movement occurred.
Step 2: Building the Dome
For the dome sides, I used sheets of 50mm (2") poly-styrene foam, with silver foil on one side, from a local supplier. I then cut them to shape of a shell, and mounted lazy suzan bearings at the fulcrum, reinforced with 1 metre (3') square sheets of MDF, coated in varnish and silver foil for water proofing.
We joined the two sides by mounting the bearings on a bar (10mm (½") threaded rod) going straight through both sides and matching lazy suzan bearings on the vertical mounts. I surrounded the bar inside the Dome with 4 lengths of 30x19mm (1½x1") wide MDF, then fibreglassed them together so as to allow the centre bar to move freely inside.
Then we used aluminium struts to attach the edges of the two sides. This took about 6 pieces of aluminium bar and angle, and a couple of pieces of 24x19 (2x1") timber at the ends. We also placed two sets of flat bar in a cross pattern to lock the sides in place.
Finally we placed flat galvanised iron sheet over the struts, and sealed the edges with plumber's tarred-tape. Later I cut up a hikers mattress (30mm (1½") thick blue foam) and glued it to the inside surface for insulation.
The purpose of insulation was to protect the Telescope and cameras from our 48 deg C (118 deg F) Summer heat. To add to this I installed a fan assisted 250mm (10") air conditioner vent from my bedroom to the inside of the dome. And for winter time I placed a portable de-humidifyer inside the dome. All gaps have been sealed with a rubber gasket, and a large rubber hanging door (it's a flap really) closes the open gap left when the dome is closed. I sewed a series of magnets around the edge of this rubber door, and with just a flick, it closes to seal the dome.
To complete the summer protection, I have a sail cloth which is pulled over the Dome via a steel cable from downstairs, This rolls back when I use the Telescope at night - although I can leave it up to align the cameras during the daytime.
I balanced the Dome so that I can open it and close it from downstairs via a steel cable with a boat winch - which can be connected to a 12v motor later. This requires a just few turns, and then the dome opens all the way on it's own. Then on closing, I wind it to the balance point and it closes on it's own.
It then locks in position with a security lock, and sets an alarm connection to the house alarm system, so no-one can pinch my telescope, without causing a ruckus and getting their photo published. Were always home anyway, so there's not much risk - because of my illness I can't travel.
Step 3: Lowering / Raising the Dome
This is not Opening / Closing, it's Lowering / Raising.
Once I started setting up the Telescope, I found that there wasn't enough clearance for the mount's counter balance weights at all angles of the mount.
After a lot of sitting around drinking coffee with my mate, we worked out the best answer was to lower the dome 500mm (20") after it had been opened.
To do this, we mounted two linear motors onto a pair of 240x45mm (9x1¾ ") treated pine boards.
On each board (East and West) we mounted the motors between two enormous drawer slides then attached the moving sides of the drawer slides to two 90x45 mm (3x1¾ ") boards which were to be attached to a further set of 240x45mm (9x1¾ ") treated pine boards attached to the Dome Bearings.
In this way I am able to Lower or Raise the complete Dome by 500mm (20") once it's opened, just with the flick of a switch. Two industrial 'Wobble Sticks' control the end of range of the motors, against long screws that I screwed into the timber.
It's a beautiful Thing!
Step 4: Using the Telescope
This series of photos show me lifting the mount and Telescope up to the pier top using the removable 'Crane'.
The second last photo shows an early setup of cameras, this has changed now that I have a CCD camera as well. Note the security camera in the background, which both gives a 24/7 recorded security view, and lets me see where the Telescope is pointing.
The last photo shows the closed Dome, behind the Solar Panels which are used to charge the 12v batteries. These batteries power the mount / cameras & security system.
I haven't covered the control equipment - I'll add a new instructable later. Basically it's two Arduino controller devices with their internal web pages, connected via WiFi to my main router.
The first one let's me monitor temperatures, humidity, magnetic pointing (separate from my computer control) etc and switch cameras on and off, and control my optical switch.
The second controller is a PID controller I made to stop my equipment fogging up, and it controls heating and cooling on all cameras and mirrors, with a web printout of the current status.