Thrush Observatory Plans

Below are a few of the blueprints drawing showing the exterior and interior plans.

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Exterior View

A six foot dome purchased from Technical Innovations will house my computer controlled Celestron 11" telescope.  The observatory is located in the rear of the house and will not be visible from the front of the home.   The dome and rectangular skirt are constructed of fiberglass and will be placed on an 8'x8' dormer.  The rectangular skirt will make the transition from a circular dome base ring to the square 8'x8' dormer.  Two electric drives motors will allow the dome to rotate throughout 360 degrees and will be coupled to the telescope slewing electronics.   This will allow the dome to move with the telescope mount as it is slewed in Right Ascension. A semi-isolated pier on a pair of 8 inch I-beams will support the telescope and pier. These I-beams will span some 15 feet and rest on load bearing walls.  When using this technique, it is not desirable to connect the pier beams rigidly into the wall structure. Rather, simply resting the beams on supports at each wall will prevent the pier support beams from twisting or tilting, even as the house "bends over" in the wind.  The I-beams and pier assembly will be isolated from the floor joists of the house to reduce possible vibrations that can translate to the telescope.

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Interior View

Heat loss and condensation can be a problem if environmental issues are not addressed. One of the advantages of an IN-Roof observatory is that you can get into the dome easily without going outside. In effect, the interior of the observatory has become a room in the house. However, while you can go into the dome easily, so can the heat and humidity from within the house. Both of these potential problems have been avoided in this observatory plan by incorporating an insulating door at the observatory entrance. Heat (or cold) entering the dome from the house will not only waste energy, but will also create a temperature difference between the inside of the dome and the outside air. This will cause air currents to circulate within the observatory, and more importantly, will cause air currents to move in and out of the open shutter. Since these air currents are different temperatures, the air in them have differing amounts of light refraction. These air currents will result in reduced quality of seeing; as you look through the telescope.

Water vapor can also enter the dome, especially from inside the house. During the cool months, the interior (heated) air of the house has a higher water content than the outside air. When air that contains this water vapor enters the dome, it meets the skin of the dome that is lower in temperature than the house. This air adjacent to the dome skin will be cooled. If this cooling lowers the air temperature sufficiently to raise its relative humidity to above 100%, then water can condense on the inside surface of the dome. This condensation can be easily prevented by careful attention to sealing the dome from the house by using an insulating door.

Adjacent to the observatory will be a 12'x9' room which will house the computer equipment that operates the telescope, photometer CCD cameras and color darkroom equipment.  The construction for this observatory is set to start sometime around August 15th.



The construction has finally begun the the observatory.  Below is a photo showing one of the two 8 inch I-beams that will be used to support the telescope pier.  The second I-beam is four feet to the right of the exposed beam hidden from view by the sub-floor.

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The next photograph show the view of the addition from the back of the house. The observatory will be constructed on the right side of the roof next to the satellite dish.

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      Floor of observatory showing telescope support beams.  

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       My son Jason working on dome base ring.

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Myself, Bob and Norbert assembling the dome skirt.

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             Norbert and Ed with the dome base ring assembly.          

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Dome base ring being lifted onto second story roof

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               Bob installs DSR ring sections on dome base ring.              

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  Norbert and I install shutter panels.

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An Exterior view of observatory after the
first major snow fall of the season.

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A picture of the telescope and pier assembly

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Observatory support electronics

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Observatory control room