Observatory
How I built my observatory.
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The fifteen-inch concrete pier sits in an old tin bathtub filled with concrete. The bath sits on two inches of sand between it and the concrete floor. I filled the gap with silicon to stop the sand getting wet or blowing away. Just under the concrete I laid a 2 inch drainpipe to send all the connecting cables through. I thought this would be plenty big enough as all the end connectors went through it with ease. But after 6 months I needed to send 2 more cables through and found this very difficult as all the wires already inside it made it very problematic. It should have been at least 4 inches. The pier is sunk about four foot in the ground. I wish I had laid the concrete all the way to the grass as I found I have to lay duck boards on the grass most of the year because it gets too muddy. It is not perfectly flat to allow for drainage off the concrete. Even with the sand damping I still notice quite a lot of vibration through the scope . To the left of the pier you can see a flat shelf of concrete to put a battery in (inside the red box). The dew shields around the scopes are made from those foam mats you get to sleep on.
This is the roll off -roll on shed I built around the scope. I built the pier and mounted the scope before I even started the shed. This way it fits it very snugly. This makes it easier to keep the atmosphere dry and above freezing point inside the shed. It's just a frame of one by two wood with chipboard sides painted with a weatherproofing paint on the outside and white emulsion on the inside. I found four scaffold pole wheels and after welding them so they do not twizzle around I put one on each corner of the shed. It moves on two lengths of angle iron screwed into the floor. I then put two clasps on opposite corners to lock it up and stop the wind blowing it away.
The reason the shed is painted white on the inside is to allow for flat fielding when I am using a CCD camera. Around the door are ten eight watt bulbs with plastic baffles in front of them. On the back wall I nailed one of those screens they show photo slides on. This makes quite a good medium to take a flat field from. As you can see my next door neighbors garage obscures part of my view to the south so the sheds height is set just below the garages height so as not to obscure my view any more.
The position of the shed took some forethought. It needed to be near my house because of electrical hookups and computer leads. It also needed to have good clear views of the sky with no street lights etc., although I decided that a good clear view of the southern horizon was good enough as every thing is visible at one time of year or another. I also considered some wind shelter to be important at the time but now on reflection this is not as important as my whole garden is well sheltered. It seems that if it is to windy in one place, it is to windy every where
This document maintained by
pete.cox@zetnet.co.uk.
Material
Copyright © 2000 Pete