My wife (Peggy) and I are in the process of doing lots of things to our back yard; building a large privacy fence, putting in a fish pond, building a secure area for our cats to enjoy some outdoor time, elevated garden beds, shrubs, you name it.  Peggy employed the services of a landscape architect to come up with a plan and we have been building toward that design.  Well, that design was created before my recent relapse into astronomy so, not surprisingly, there was no observatory in the design.  So my first thought was to build the observatory on top of our detached two-car garage which sits at the back NE corner of our property.  The plan was to have a section of the roof roll away to allow a view of the very restrictive amount of unobstructed sky that is available.  I live in an older neighborhood (known as Beverly Hills, of all things) in northeastern Baltimore City.  The neighborhood was built in the mid to late 1920s, and features lots of mature trees.  I really love the house, but I would have chosen differently if astronomy was a consideration when I bought it in April of 2000.  

One of the necessities of a second floor observing deck is a rather substantial pier, usually made of concrete.  It turns out, however, that our property is only mere feet above the ground water level, so building the sort of foundation that a 12-foot high pier might need (a pier capable of holding a 20-inch SCT was my goal) was either not going to be possible or would require some novel (and expensive) techniques.  Given I just didn't have the money to do the garage adaptation I negotiated with Peggy for a bit of real estate for a free-standing observing station.

My first plan was for a roll-off roof building, about 8 feet by 10 feet in size, to be located right in front of the garage.  The telescope itself would be located exactly as shown in the pictures, above.  When I showed the plan to Peggy she pretty much hated the idea.  No matter which direction the roof rolled off it was going to seriously impact our plans for the back yard.  So I went back to the drawing board.  Plan B was to build a small platform around a concrete pier.  The telescope would reside in a removable box that could be rolled or folded away.  I would then build a small control room in the front part of the garage; the picture above left shows the garage - the left side overhead door was to be replaced with a small window and conventional door, behind which I'd build a small insulated room.  The plan morphed a bit until it became an 8-foot octagonal deck upon which I'd mount a 39.75" square box to protect the 'scope when not in use.  The 39.75-inch dimension was chosen to make it possible to use the sides of the box as wind break/walls/light shelds that could be attached to any four sides of the surrounding octagon, as each side of the 8-foot "diameter" octagon was 39.75 inches wide.  With that plan in mind I grabbed the sledge hammer and, on June 6th, 2006, began chipping away the section of concrete driveway over which I'd build the observing deck.

Here's the result of the first couple of hours of work.  Its amazing how many times the road to the stars begins by going through the earth!  This was all it took to produce a fine crop of blisters.  For one thing, it turned out that my driveway had been been poured twice, so that the concrete was as much as 10 inches thick.	After more than a week of truly back-breaking work I had managed to remove most of the concrete.  Note the JMI case just inside the garage door.  Also note the thickness of the concrete.  My blisters had blisters.	Here's the rubble pile that resulted.  It cost me $400 to have someone haul it all away!
The concrete pier has a 16-inch square base that extends 24 inches below the ground level shown here.  In fact there is an additional 6 to 8 inches of soil that was added after this picture was taken, so the base actually rests about 30 inches below ground level.  The round, above-ground section was poured in a sonotube; I also ran 4 bars of reinforcement rods up through the entire pier until about the top 8 inches.  I bought a "Dan's Piertop Plate" and CGE adaptor, also shown here.	After letting the concrete dry for several days I peeled off the sonotube and mounted the scope just to see what it would look like.  Note the pier is far from vertical.  In fact the first sonotube ruptured during the pour and I had to frantically clear out the old tube and wet but rapidly setting concrete, get a new sonotube and more concrete and repour the top four feet of the pier.  I wasn't too concerned that it was tilted a bit.  I also had a devil of a time getting the "J" bolts  that hold the pier top plate to sit properly.  They also are not vertical and severely limit how much I can adjust for level.  Luckily I WAS able to get it level.	And then a funny thing happened.  My next door neighbor decided, with out any suggestions from me, to entirely remove one large birch tree (the remaining trunk is still standing, at left), and to eliminate a limb of a large oak tree (the right edge of the picture), both of which obscured my southern sky such that I essentially could not see anything south of -5 degrees declination.  This view is directly south.  I can now see down to about -30 degrees, though only until about a half hour past the meridian.  Still, what a stroke of luck!

     Pouring the pier was nearly a total disaster.  In fact a PED, or "Pier Erection Disaster".  Just as I was adding the last bucket of concrete to the top of the 12-inch diameter sonotube I noticed a bubble near the form's base.  Apparently I had gotten a few drops of water on the outside of the tube while mixing the concrete and that was enough to compromise the tube's structure.  Within a couple of minutes the tube had ruptured near its base and was slumping over.  I frantically ripped apart the tube and gathered as much of the concrete as I could into the wheel barrow.  I removed all of the wet concrete down to the square base at ground level, then dashed off to Home Depot to get a new tube and some more concrete.  I raced back home, set the new tube over the reinforcement rods and onto the square base form, then poured the drying mix from the wheel barrow into the tube.  I added newly mixed concrete to fill it to the top and stood back to see if this tube would suffer the same fate.  After a few minutes I was convinced that this tube would hold, but in all of the panic I had forgotten to set the pier plate J-bolts in.  I had purchased a Dan's Pier Top Plate and CGE adapter to put on the top of the concrete collumn, and the plate sets on three 3/4" J-bolts, which need to be accurately positioned and set vertically in the top 6" or so of the wet cement.   I already had them attached and tightened onto the plate so they would be properly aligned, but when I tried to set them into the concrete it was clear I'd have to use so much force that the sonotube form would again collapse.  I didn't have much time; I couldn't think of anything else to do so I removed the bolts from the plate and tried setting each one individually into the concrete.  That did work as far as getting them into the concrete without rupturing another sonotube, but the alignment was way off.  I tried attaching the pier plate and gently twisted and pulled, twisted and pushed, until I got it where I thought it would work.  I used a level to get it as close as possible, then left well enough alone for fear that I might destroy the whole mess. 

The next day I went out to assess the damage.  It wasn't a pretty sight.  The pier was visibly out of vertical and was slumped a bit toward the north.  The J-bolts were not vertical and it was not possible to remove the plate as the angled bolts caused it to bind up.  I was able to turn the lower nuts with a large wrench and by working slowly and turning each bold just a little bit at a time I was able to get the plate to where I knew I could remove it.  I decided not to do so as I was afraid I'd never get it back on. so I began running the nuts back the other way, slowly working down the length of the J-bolts, hoping to get enough to be able to tighten the top nuts so as to secure the plate.  Well, I did succeed, but at a price; one of the lower nuts is now completely bound up due to messed up threads and metal shavings.  Still, the other two bolts were somewhat adjustable and I was able to get it level.  Like I said, not a pretty sight, but it worked and is solid and level.  Whew!

Once the pier was done I back filled the area where the concrete had been removed, then dug the eight holes for the 4x4 posts which would secure the octagonal deck.  Each post was set about 24 inches deep in concrete.  The octagonal deck was built from pressure treated 2x6 for the joists, then standard 6-inch wide 5/4" pressure-treated deck boards for the floor.