Up to Date on Construction!

In the last post, you saw the walls and siding of the back yard observatory going up in a day's work.  It was a few days later till we got back to it with John's schedule, and my task was to work out the final pivot dimensions for the roof. I made another larger-scale model and found there were so many variables that it was tough to finalize.  Generally, some notes are shown at left.  The outer pivots attach near the roof Center of Gravity (CG), and will be counterweighted to assist in lifting the roof off the walls as well as starting the roof closed.  The inner struts, attached to the center roof pivots, are mostly for guiding the roof, perhaps partially counterweighted.   As far as the roof pivots were concerned, they could be attached, so after an aborted attempt to install the door, construction resumed on 5 December.

The original door installation was complicated by the 6 foot wall height.  That meant a good foot was chopped off the door, including the lower hinge.  That reduced the stability of the door to the point that John had difficulty getting it to hang properly.  After an hour's effort, without the right tools with him and with me still uncertain about pivot locations, he left to go paint houses to return another day.  This day with the right tools, he remounted the previously sawn-off hinge and it then behaved normally in its installation.  Now, with the gentlest of swings, it closes and latches nicely!

After that old business, it was on to
installing the pivots on the roof sections.  I had made the pivots out of 1" diameter solid steel shafts, welded into 3" angle iron to facilitate attachment to wooden frame or welded to the roof frame.  There is also a tapped hole in the shaft to hold on the expected struts that will be mounted.  I marked out where I wanted them and John made good use of his welder to attach them permanently.  At left, he welds one at the center of the roof section that faces outwards (another already mounted above his helmet), and at right he welds one on the inside of the roof section.

Note in the previous image that the inner pivots are not well supported, welded only on the inside 2" of their 6" length on the roof tubing.  I had gotten some 2X3" steel tubing to reinforce them, and at left John again uses his handy grinder with the cutting blade to chop them to 6" lengths to weld on for reinforcing.  In addition, I fabricated some hefty hold-down brackets from 3.5" heavy-duty angle iron.  Particularly with a mostly counterweighted roof, I didn't want roof sections flying off in inclement weather!  With these brackets welded on (shown at right), with the six 3/4" bolts holding the roof on to the observatory frame, it won't be going anywhere!

Finally it was time for a roof!  Using
galvanized steel roofing, after deciding on how long to overhang, he chopped them off (again that grinder/cutting wheel) to the right length before hoisting them to the roof frame for attachment.  Starting on the top, on one end, he went along and fastened them down with self-tapping screws into the metal frame.  There is a little washer with rubber grommet that seals out weather from future storms... 

As you can imagine, with pretty large sections, it went up pretty fast, with a couple ribs overlap between sections.  Battery-powered tools are wonderful for working over a large surface without running an electrical line.  The hex-head socket is also great to get in the screws without stripping-out the normal Phillips head screws...  Before I knew it, he had all the roof sections on, and attached a center span to seal against weather (attached only on one side for roof removal). 

Since this was our last work day until after the holidays, I had asked him for a "bill-to-date".  Interestingly, his labor was pretty much exactly the same as the materials used!  I'll likely provide a final cost when we're finished.  The only work remaining is electrical (which I'll likely do with friend's volunteer effort), finish sealing the roof with siding, and building trim.  I'm sure he wants to see how well my plan for the removable roof works, which I'll attack over the holiday as well.  Then it will be finished 'cept for the telescope part - a whole 'nother story. 

After my van collision and the anticipated totaling-payoff, I've moved all the astro and camping stuff into the now-weathertight observatory.  Lots of room to spare, so there was more room in there than it seemed!

Update on the Back Yard!

When I last did an update on the back yard observatory, I had hired a building contractor, John Vermette, who came in and had a concrete pad poured 8 days after first meeting him. Since then, it seems like progress has been made at the speed of light, certainly orders of magnitude (factors of 10) faster than if I had tried to do it myself! I don't want to bore you with all the details, but at the same time, I think it might be valuable to others to see how this one has been done.

After pouring the concrete pad on 19 November (a Wednesday), I was to keep it watered down to prevent premature drying for a few days, and at the same time, keep off of it while it cured. By the weekend, it was at nearly full-strength, and I wanted to hoist the mount in place, as I didn't think I wanted to try it through a doorway. With John Davis' assistance and a borrowed engine hoist from work, it was done in a flash. At left, I had wrestled it in place, and at right, the job done, Mr. Davis gives it a once-over...

The next day, a Monday, John Vermette was there ready to work!  I got to help out as assistant so he didn't have to hire another helper.  While he had the expertise, and knew what had to be done, I learned and made the tasks a little easier for him...  For a small building this size (10X10 feet), you could likely do it yourself, but it goes easier and more quickly with two, and unskilled help like me was perfect for this application!

After ripping out the forms for the now-hardened concrete, he set to work to put up the walls.  I didn't have a chance to take lots of pictures, but in two hours, it went from a stack of lumber to recognized upright 6-foot tall walls.  Of course, the walls are firmly fastened to the slab with the j-bolts sunk into the concrete.  While we don't get tornados here, we get dust devils and huge gusts from monsoon storms, so this building isn't going anywhere without taking the slab with it!

Another two hours and the siding was on!  Shown here is a view through the only entrance now, the doorway - a two-frame mosaic.  It was amazing how much more sturdy the building became by adding the skin of the wood siding.  And with this all going up in 4 hours, it was amazing to get the feel of its appearance...

Two days later, John was back to work on the roof.  In his normal roll-off observatory construction, the roof is one piece.  I wanted to avoid the footprint of the additional area of the rolled-back roof support, and have a fold-down roof.  So his roof construction was a 2-piece and will split down the center.  At left he cuts the 13 gauge steel tubing with a grinder and cutting blade, and at right is welding it in place atop the wall with his MIG (Metal Inert Gas) welder.  With his use of magnetic clamps and his frequent welding, I had more chance to take photos during this stage.  His layout of both the walls and roof are quite accurate - he kept a square in his pocket for checking EVERYTHING, and his level was similarly often used in the wall layout.

The layout and welding similarly went
quickly on the roof sections too.  Again, less than 4 hours from start to finish.  At left is another welding shot, and at right is the finished product showing the two roof sections, split in the middle.  The metal frame helps keep the roof sections light weight - definitely needed for this fold-down design, but also used in his roll-off for its strength and rigidity.  I think he also enjoys the variety of metal/welding incorporated into his carpentry.  A little variety in the tasks always makes the job more interesting.

I didn't want to make this post too long, so will have another entry upcoming on further progress - that one will bring us up to date on construction.

Current Status of the Backyard Observatory

My last post brought you up to date in mid-April when the telescope pier was poured.  With the heat of summer, it seemed prudent not to schedule any work in the yard, so I waited for cooler weather.  As shown at left, the pier was pretty much unchanged for 7 months until Fall arrived.  With the astronomy Expo a couple weeks back, the idea got kicked to the front of my thinking and the evening we spent at Starizona I asked Dean Koenig about a contractor he recommended for observatory construction. 










The following Monday I called his recommendation John Vermette, we visited the observatory in his back yard the next day (Veteran's Day), and 6 days later he was in my yard building concrete forms!  Originally I was thinking of a 12 X 12 foot floor, but with it laid out, it just seemed so huge - taking up so much space in the yard that I cut it back to 10X10.  The interior will be cozy, but most of the time I'll likely be by myself there, so should work out ok. 

John is willing to let me jump in and help him, hopefully saving him some time and me some money, and I do some things on my own.  For instance, while he built the forms for the slab at left, I put in the trenching and ran conduit for the electrical line that will get buried underground and under the slab for power, shown at right.  He called me later in the day on 17 November - the concrete was coming Wednesday morning!

So I had a few more tasks to do before then.  I needed to clear, or at least move my "storage pile" against the fence as I would need to remove a section so the cement truck could directly access the yard.  After pouring the pier in April, I couldn't see doing a slab in small batches, so ordering a truck seemed the best route to go.  John ordered 2 cubic yards for the lil' slab I needed...  At left you can see my effort in removing the fence for access, and the layer of foam around the pier base to isolate the slab from the telescope.  John is watering down the ground so the dry dirt doesn't pull the water out of the concrete too fast.  At right, the truck has arrived, and he and the assistant he hired to help an hour or two were working hard on the pour.

I also invited our buddy Frank, who had helped me with the mixing and pouring of the pier in April.  Realizing the truck would likely have extra, in the space of a few minutes, he rigged up some forms from old 2X4s to pour some "stepping stones" to lead up to the entrance of the observatory door.  At left, as the slab form is filled and the guys were working on that, Frank is in the back, ready to pour the sidewalk sections.  After pouring and letting it set up a bit, he worked on finishing these sections.  Once cured, they'll be separated from the forms, and bedded in a base of sand for a permanent path...

Meanwhile John was taking care of business on the slab.  While I've seldom worked with concrete since leaving the farm back in the '70s, it was fascinating to watch someone who knew what they were doing with the right tools.  I suspect the flat-screened tool at left serves a similar purpose to the vibrator I used on the pier.  By jiggling the tool, it works the bubbles to the surface to make a stronger slab.  At right, he puts a groove into the slab so that if it cracks, it will crack in a controlled manner along it.  You can also spot the "J-bolts" installed around the periphery of the slab, which will hold down the walls of the building securely.

Over the next couple hours as the concrete set up he continued working the surface, smoothing out the top and filling in what looked like little cracks, believing that the dry air was causing it to dry too quickly.  I think he was a little paranoid, as a few days later, it looks fine, though still looks far from fully cured and dried.  I followed his directions and hosed it down occasionally. to keep it from curing too fast... 

On pour day, he also brought the supplies that he'll use for building the observatory.  At right, the current status of the observatory is shown.  The slab, siding at left against the now-replaced fence, a pile of 2X6s, the metal door at center leaning against the far fence, and at right is the blue equatorial mount, with a wooden cover over it to keep weather out the last couple years.

Progress will be made quickly as John is coming Monday to frame up the walls and the door will go in by Tuesday.  The roof, following my fold-down design, will take longer, but he'll build it in place and we'll work on my plan together as his schedule permits.  Meanwhile I'm thinking I've got to get the mount installed before the walls go up - tomorrow is installation day!

Update on a Backyard Observatory!

Some of you with good memories might recall a post I made last February about my backyard observatory project.  Since our yard is rather small, I envisioned a design I'd not seen before, even making a small working scale model, shown at left.  It has the advantage of not requiring permanent space devoted to poles and rails to support the roof while removed.  I had also obtained a decent-sized telescope a few years back from the estate of Lloyd Horton - a beefy 12.5" telescope he made back in the 60's .  It needed an equally beefy pier, but was perfect for an in-town observatory for observing the moon and planets. 

Things have taken a big jump forward in the last couple weeks with my locating a building contractor willing to take a risk with my design.  And since he is also an amateur astronomer, he finds working on my little observatory more fun than his remodeling projects, so bumped me up in the schedule!

But first, I realized I'd not posted on the progress made way last Spring!  In April, just before it got ungodly hot in Tucson, work was started on the observatory over a LONG weekend by deciding on the exact location and installing a pier for the mount and telescope.  It has a pretty good-sized footprint, so needed a 24" diameter pier sunk into the ground, to be isolated from the observatory building.  From my reading, such a large amount of concrete needed some steel rebar, so I visited my local concrete supply place for cardboard sonotube, rebar and rounds for proper strengthening.  Starting with straight 1/2" rebar (#4) and a hefty piece of pipe, L-shaped pieces were made and wired together.  The round pieces were placed closer together at the bottom and top of the pier for added strength there.  The cross pieces of the structure shown at right helped keep it centered in the 24" sonotube form. 

The hole had been started before, but was deepened and enlarged to accept the form and rebar.  It was then leveled so that it was exactly vertical in the hole.  I also added some conduit so that electrical power could be run under the building slab up into the center of the pier to get power to the scope without cords to trip over...

In addition, before pouring the concrete, I borrowed a transit from work to take a sighting on Polaris, the north star, to establish a north-south line with which to align the pier and mount.  With Polaris at upper culmination, ie above the pole, but exactly north, I made a mark on the air conditioner and outer fence to stretch a N-S string when the time came...

The next day (Sunday, 13 April), Frank Koch came by to help with the concrete work.  He is the husband of a friend and work mate of Melinda's and he is quite the friend to have, volunteering to help with pouring over a ton of cement on a hot Spring day!  The one advantage of casting the pier was that the mixer could be parked in one place and just dumped into the pier location.  His mixer was a beefy gas-powered model, which hadn't been used in a while...  After spending the better part of an hour rebuilding the carburetor, it finally ran great and we got mixing.  Frank hoisted the 90 pound bags of concrete (26 of them!) into the spinning mixer and I added water to get the correct consistency. 


Of course, I had the easier job there, but I also used a vibrator (visible in the wide shot at left) that I'd rented for the occasion to make sure there were no air bubbles down around the rebar that would weaken the structure.  So between Frank's hoisting bags, and my adding water and vibrating the form, we were a well-oiled machine!  It seemed to take no time at all before we neared completion.

Of course, Melinda took most of these pictures, and got just the last couple batches of concrete mix to go into the form.  At left, Frank is dumping the mix, and at right, the last little bit goes in and we start work in smoothing the top surface and cleaning up.

After working the surface and allowing it to set up a little, it was time to insert the J-bolts that will fasten to the mount.  They had been installed on a plywood square pre-drilled with the correct bolt pattern.  In addition, lines were drawn on the square so that the bolts could be aligned N-S along the line laid out with the transit aligned to Polaris.  While a little nervous if I did it all right, in a day or two, the plywood was removed and the mounting adaptor slipped right into place - just like it was supposed to!

So that brings you up to date to April!  Like I said, lots has happened the last week, but that will have to wait for another post...

Another Home Improvement Task Finished!

While I don't think we'll ever be "finished" with our 80-year-old cottage in the woods, we did complete a task that has been hanging over our heads for a while.  The days when we moved walls and tore into electrical and plumbing work seems so long ago.  This time we wanted to finish re-doing a pair of windows in the kitchen.  These windows, long exposed to the elements, needed replacing of the glazing and repainting badly before we finish the final touch-ups to the kitchen and declare it done.

Sister-in-law Maj had pulled out the windows in advance, and as Melinda worked on repainting the trim (at left), we started chipping out the glazing from the wooden sills.  Most came out easily, but as it likely happens, we also cracked a couple panes of glass, so had to replace some.  Interestingly, we lost a few days in getting glass - the hardware store misunderstood and assumed we wanted them to glaze the windows instead of cutting the glass to fit, as they usually do.  Finally, 3 days into the wait I asked them and apologetically cut the glass for me.  Glazing is the fun part - why wouldn't I want to do that myself?!

I remember summers past out in the miserable heat of summer chipping out glazing, but this summer has been amazing!  It has been so pleasant, especially working outside where temps rarely passed 85F and was usually in the 70s.  With the windows in hand, glazing or patching those in good shape only took a couple hours in the shady confines of our yard...  It took a couple days to stiffen enough to trim the glaze and paint the windows.  We didn't have to worry about getting paint on the glass as a razor blade will scape it off easily after the paint dries.  Melinda paints the wooden sills in these shots.  Don't worry - I helped too!

Maj came out frequently too, helping out with the windows and landscaping around the house.  She is a natural-born gardener and will jump into pulling weeds, trimming bushes and trees, or using the leaf-blower to clear the 3-year-old shingles, roof and downspouts...  At left she oversees the window installation.

The inner trim was the last task, cut to size and painted after the windows were installed.  At right Melinda pre-drills the screws to mount the trim.  I filled the trim cracks w/caulk, and installation was nearly complete.

We figured we were on a roll, and started hunting down the curtains and hardware that had been removed, what, 3 years ago when we had the roof redone.  All that found, we  started drilling and screwing, remounting the hardware.  At left is a rare picture of me working (mostly 'cause I'm taking the pictures), installing curtain rod brackets.  Finally at right is Melinda doing her best Vanna White impression showing off the final product - looks great!

Backyard Observatory Project!

In recent years, I've been thinking more of building a back yard observatory.  While Tucson skies are okay for a city of nearly 1 million (brightest part of the Milky Way just visible on dry nights), it just isn't suitable for dark sky observing.  But there have been lots of times that I've wished there was a ready access scope for checking out a planet or lunar view.  It is a real pain to set up a scope out of the house or van, then have to put it away again afterwards.  A couple years ago, I even obtained a telescope from the estate of a telescope-maker north of Phoenix - a 12.5" Cassegrain, perfect for such applications.  It has patiently been waiting for its moment in storage for construction of a structure.  Our back yard is a little small, though, so have been giving some thought to what to build.  While one where the roof rolls off is straightforward to build, the supports and frame for the roof while it is off the building automatically doubles the footprint.  A dome might be nice, but are expensive in larger sizes, and I dislike the restrictive sky view out of a dome slit.  What other options are there?

A friend of mine, David Oesper built a really neat observatory design a couple decades ago.  It was featured in Sky and Telescope magazine in May of 1993, and the photograph shown here is from that article.  The roof panels roll down a rail, while supported by a pivoting strut and counterbalanced with weights inside the structure.  David is shown here at left with daughter Julie (now grown) and their builder Andy Orngard who came up with the design.  It has no structure outside the building when closed, which fits my desire.  However, the steep roof angle isn't needed in Tucson (no snow or ice), and I couldn't figure how to modify it to work with a shallower roof.  Another good feature of this design is keeping one side of the observatory up to keep out wind or an obnoxious light.

So I was thinking of something similar but wanted to go larger because of the larger scope and having room for a friend or two.  I gave up the rails and tried running off  pivoting struts.  Using paper and cardboard models in 2D only get you so far, so I decided to make a scale model out of wood, about 1:12.  This is what I came up with...  Shown at left with the roof closed, it is 10X10 feet inside clearance, and the outer walls are 5.5 feet high, with the peak of the roof 8 feet high when closed.  With the roof open, as shown at right, the 2 struts per side rotate the panels up and out alongside the building, providing good horizons in all directions.  The little stick figure is nearly to scale for a 5 foot tall person w/a 3" refractor.  The roof sections reach a balance point about half way open, so like David's design, would need a counterweight system to aid in starting it opening, and to catch it as it reaches its open limit.

A shown in these pictures, it also works, like David's with one of the roof panels either partially open or closed altogether.  Although not shown well, the pair of struts do NOT work off the same pivot.  Different pivots points and strut lengths are needed to get the roof moving up off the walls, fully clear the rear wall and then to stay close to the wall when it is open.  The struts would scale directly to a full-size building, perhaps aluminum bar stock 4" to 6" wide and 3/4" thick or so.  The weight of the roof panels rests on the rear wall via the inside strut when fully open.  Pivot axes made of 1" steel shafts could be made into an angle-iron bracket to be fastened to studs in the wall for strength and security.  And though I haven't figured out a door yet, the 5+ foot tall walls should allow easy access from outside.

Not wanting to rush into anything, I'll likely dig a hole and put in the telescope pier first, get the mounting installed, and perhaps even the telescope too before building the observatory around it.  But I think the design has possibilities.  If any of you see why it won't work, let me know or come by and play with my little model with me!