Eagle Rock Observatory

Initial Planning

Choice of Instrument

It makes sense to have a specific instrument in mind when planning a observatory building. With this in mind, I started investigating possible telescopes in early 2007. My informal schedule for building the observatory was a couple of years out at that time. As it happened, I found a really attractive price on a 16-inch RCX400 that had been used as a display model. After a weekend trip to the store to look over the scope in person, I decided this was the one. Within two weeks a 500-pound pallet was gently landed on my driveway.

This telescope was much too big to haul out to the existing observing pad, and needed a permanent setup. It was time to build the observatory.

The packaging of the telescope, on a wooden palette and secured by plastic wrap, is worth noting. I have seen postings in some forums reporting RCX400 problems -- even for telescopes shipped directly from Meade -- apparently due to the scope's poor tolerance for being shipped. After fairly extensive usage, my telescope has shown no such problems. The solid packaging may be at least partly responsible for the trouble-free performance of the telescope.

Type of Building

After the telescope, the major design choice to be made was roll-off roof vs. dome observatory. I have always admired roll-off roof designs, primarily because of the all-sky view and the feeling of open space. For the new observatory I somewhat reluctantly chose a dome design. The choice was driven by the site. Wind is always an issue at my location, and for much of the year it brings a biting chill. I don't think a roll-off roof would provide enough shelter, unless the walls were so high that they would cut off some of the view to the horizon.

A second consideration was light pollution, from three sources: fast-growing Idaho Falls to the northeast, neighbors' porch lights, and headlights of passing cars. The dome minimizes distractions from all of these. I especially enjoy the quiet, peaceful environment inside the dome when observing. It allows me to focus on what I am doing.

After review of the offerings for prefabricated observatories, including visits to existing installations, I chose the Technical Innovations 10-foot ProDome with four-foot side walls. The 10-foot size provides enough space for me, my equipment, and a couple of guests.

There was, and still is, a case to be made for installing the dome on conventionally built frame walls. However, at the time I thought that putting up the entire structure from pre-fabricated parts would be the simplest and fastest approach.

Site Selection

With a lot size of over two acres, I had some flexibility in the choice of the observatory location. I ruled out the location of the existing observing pad, because a neighbor was planning to build a large structure just east of it. The following criteria seemed important:

• Far enough from from the property line to satisfy local covenants
• Far enough from the residence to minimize the amount of sky it blocks
• Does not block the view to the North or West for any existing or prospective neighbors. The view, of five mountain ranges up to 80 miles away, is a major reason why many of us live in this neighborhood.
• Minimizes blockage of the sky by any existing or prospective neighbors, especially to the South and East
• Outside the range of the existing sprinkler system. The major watering of the lawn takes place at night, during prime observing time.

I chose a spot about 125 feet southwest of the residence, with a clear line of sight to the horizon from Southeast through West to North. A few rooflines extend above the horizon, but not more than two degrees.

Approvals

I live in a neighborhood controlled by covenants, and any new outbuilding such as the observatory has to comply with those covenants. The only significant restriction is that the building must be at least 20 feet from the side property line and 50 feet from the rear property line. That's fine with me; I prefer to keep my distance from other houses. Obtaining approval from the Architectural Control Board was straightforward.

I also took it upon myself to minimize the effect of the observatory on any of my neighbor's views, and to make a courtesy call on each of my neighbors to inform them of my plans. Idaho is a great place to live -- I have fine neighbors, and no one raised an objection.

As a final courtesy, I chose a color for the observatory that coordinates with our own house and the general trends in the neighborhood. A white or silver dome might look very astronomical, but it would stand out like a sore thumb in a cluster of earth-toned residences!

The most important approval is, of course, by my remarkable wife Laura. She has been consistently supportive of my astronomy activities, which consume my time and our resources. I consider myself fortunate to have such a continuing source of support.