First Sawdust April 3, 2004

The 2-meter aluminum Observa-Dome that I purchased used from Hands On Optics of Damascus, Maryland.

April 3, 2004

This is the photographic chronicle of the construction of a small astronomical observatory at my home in Gambrills, Maryland (39° 04' 38"N 076° 39' 33"W). “First Sawdust” was achieved on April 3, 2004, though permanent installations, i.e., pouring of concrete, will not begin until after April 15, the deadline for objections from the other eight households in my homeowners’ association.

The first part of the project is the construction of a wood base for the dome. The wood base will be an octagon approximately 4-feet in height (exact height to be determined by experiment on the next clear day) and 78" across parallel sides. There is a rough diagram of the base here. The base will be constructed of 2x6 lumber with a pressure-treated sill plate and an untreated top. Wall studs, also untreated, will be 16" on-center. Exterior finish will be cream-colored siding to match my house.

The concrete base consists of two parts: First I will pour a column for the pier. This column will be 18" in diameter and four-feet deep. The second pour will be the concrete base to support the wooden structure and dome. It will be octagonal in shape, eight inches thick, with an eight-inch thick by 30-inch-deep footer all around. It will be a monolithic pour, and it will be isolated from the concrete pier base. The pier base will be flush with the concrete pad, as I will mount the telescope on a steel pier. There is a map of the location of the dome with respect to my house here. Although I have a two-acre lot, the location of the observatory is constrained by trees and other features. The location that I have chosen will provide a clear view to the north, east, and south. The view to the west and southwest will be entirely blocked by my house.

The observatory will house an 8" Meade LX200 GPS and sometimes a Questar Duplex. The Meade will be mounted on a Milburn wedge that I have just received. The Milburn Wedge will be attached to an AstroPier “Aurora Model” that I will order upon determining the appropriate height -- I am again waiting for clear weather. According to LeSeuer, makers of the AstroPier, it must be mounted six inches due south of the dome center at my latitude. The Milburn wedge is beautifully made, and a full report is forthcoming.

12-foot lumber in a 6-foot bed. The versatile load-handling hardware of my Nissan Titan made it easy. The sill plate for the dome base is pressure-treated lumber, while the remainder of the wood is untreated.

My DeWalt Compound Miter Saw made short work of cutting the sill plate and top plate and the wall studs.

Yours truly with a symbolic first wall section. It will be disassembled and all plates will be trimmed slightly on the table saw on their short sides, as the 2x6's are of uneven width. My thanks to those who have reminded me that the standards of and fit and finish for general carpentry are somewhat less rigid than those for fine cabinetry. I was unaware that wall studs don’t need to be made of bookmatched rosewood; this knowledge will save me several thousand dollars and knock several months off the construction time.

(By the way, those are Carhartt Arctic bibs with quilted lining from the waist down. They are great for cold weather observing when combined with thermal underwear and other appropriate clothing.)

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