25.03.2025 Demolition restarted:

 ~*~

  Tuesday 25th An overcast day. I went back to demolishing the observatory. I had influenza since my last bout of demolition/disassembly. Then had problems with my leg muscles. After overdoing the squats with weights at the gym.  Yes, I know that sounds silly. I am 78 next month.

 First I removed the expanded timber structure meant to support the 4.3m/14' GRP dome. This involved a lot of ladder work trying to reach recalcitrant screws. The outer plywood cladding had to be taken down first.

 During the day I returned at intervals after having rests and pausing for lunch. And a one hour nosebleed before lunch! I am on several blood thinners for heart problems.

 In the afternoon I removed the cladding on the 14' tall pier. With further difficulty due to poor quality Torx screws and difficult access. Then I removed the observatory's double doors. With yet more difficulty due to more, poor quality, Torx screws.

 The structure is looking ever more open. With views across the back field to my distant neighbours. I am making no effort to be tidy as I work. Preferring to make a heap. For sorting later. After making the best possible progress on dismantling the building.

  ~*~

4.03.2025 Demolition continues.

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  Tuesday 4th. A sunny but breezy day. Fortunately I am mostly sheltered from the west.

 I am continuing to demolish my observatory. I laid two ladders across the building and then lifted and pushed the heavy dome base ring over the edge. It broke once it was overhanging. Though still held together by the rubber skirt. I used scissors to free it. So that it fell to the ground in pieces. Without damaging the adjacent shed.

 Then it was a matter of undoing 32 galvanized nuts to free the dome rotation rollers. Which was rather time consuming. Despite the use of a socket set and long drive extension. I had to stand on a low stepladder to reach each roller. There is not much left that is worth saving from the building now. Except the timber of course.

The next image shows the debris is building up in front of the observatory. It seems best to allow the waste material to fall onto the heap. To be sorted later. The dome rotation rollers are now absent.

 I continued work in the afternoon. When it was sunny and reach 51F/11C and I made rapid progress. Yet again I was delayed by crap Torx screws and or/bits. Requiring constant changing to new bits. To avoid them spinning in the screw heads.

 I have now shifted my attention to the rear of the building. Where there is a 90cm/3' drop off the gravel foundation pad. Unless the plywood is released I cannot reach the long screws. Which are holding the skeleton together.  

 16.00 and I have come back in for a rest. It is quite hard work going up and down the ladders. The battery powered screwdriver demands some pressure applied to the many screws. All of which are skewed and on the outside of the building. Meaning I have to hang over the drop while clinging to the upright posts.

 It is rather depressing having to take down all my original work. In designing and building the observatory as I went along. I wish I had made the building further away from the shed. It proved all but impossible to access the nearest panels and structure because I could not bring a ladder to bear. So I made a short roof ladder and leaned across from the shed roof. Which itself, is rather fragile. A corrugated asphalt and paper lamination called Onduline. I built the shed myself over 20 years ago. 

 Saturday 8th:  Demolition was paused to due to flu.

 

 ~*~

3.03.2025 Observatory demolition: Mounting removal and dismantling.

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  Monday 3rd. It was a dry and fairly still day. With occasional sunny periods. I decided to bring down my massive, home made, telescope mounting. 

 It is so heavy that it needs a chain hoist to lift it off the 14' per. Supporting a heavy chain hoist required two ladders. Arranged to face each other and lashed with a lifting strop so they become an A-frame. I use folding builder's ladders. Though heavy they allow me fold them before climbing the internal stepladder.

 I started by removing the heavy, declination axis. A solid bar of stainless steel 50mm [2"] in diameter. I managed this manually. After releasing the assorted clamps and spacers. 

 Then it was onto dismantling the mounting while it was still in place. The big stepper motors, worms and wormwheels all had to come off. The curved edges of the wormwheel lock into the worms. Making removal impossible. The heap of bits was beginning to add up on the observatory floor. 

 There wasn't enough free distance to lift the polar axis shaft out of its housing. So I lifted the PA as a complete unit. By removing the 16mm PA altitude pivot and its adjusting turnbuckle. After that I could lift down the PA support fork. 

 Removing the PA shaft required some dismantling of the PA housing. To allow free axis to the double tapered, engineering clamp. I started by removing one of the massive, flange bearings. Every nut has to be loosened to allow disassembly.

The image [right] shows the compression construction I used. To allow flat plates to make a very rigid box. Without having to use a casting or welding.

 The large corner studs are 16mm and galvanized. These compress the box longitudinally.  They are deliberately positioned in the exact corners of the box. So that the plates rest against them. This ensures stiffness when compressed and there is no lateral movement of the 10mm aluminium plates. The downside is weight. Which I considered a low priority for an observatory class, equatorial mounting.

 The circle of hex socket head screws is where the box is Tollok clamped to the 50mm shaft. The box is criss-crossed with 8mm steel studs. Using hex socket, furniture nuts to tighten them. 

 All of the studs were positioned to lean against those at right angles. This further ensured there could be no lateral movement of the box panels. Compression starts with the heavy, cast iron, self-aligning, flange bearing housings. Further reinforced by all the other studs clamping the plates tightly together at right angles.

 The longer studs [at centre] pass right through the box and into the 180mm/7" Ø, aluminium cylinder. Against which the housing sits. The clamp fits inside this cylinder to resist expansion. This further avoids any possibility of flexibility at the joint. 

 The cylinder acts as a stabilizer to the axes joint and the studs a larger clamping circle than the clamping screws. These Tollok clamps are used in engineering. To mount heavy drive components to machinery. Chain wheels and multiple V-belts are often used. Where easy dismantling is vital to continued maintenance tasks under heavy loads. 

 To dismantle the shaft clamp the holding screws are simply loosened. Then new screws inserted in the separation holes provided and tightened. The Tollok clamp then slide apart. It is important to use a torque wrench when assembling.

I was careful to grease all the studs and nuts to allow later dismantling. I started building the mounting 8 years ago in early 2017. All of the aluminium came from a local scrap yard at very modest cost. Mostly in long strips. Which dictated the width dimensions of my mounting. The polished, 50mm stainless steel axes were kindly supplied by a local engineering firm at cost. 

 The inexpensive, self-aligning, flange mounted, ball bearings nicely matched the maximum dimensions I could achieve from my materials. The bearings have proven to be shake free and very free moving in practice. 

 This 2017 image better shows the construction. When I still had the RA wormwheel at the top of the Polar Axis. [PA] This was with the 180mm/7" Star refractor mounted in its folded form. The mounting's Achilles Heel was always the pathetically weak Beacon Hill worm housings. Fitted with simple ball bearings in sawn lengths of channel section aluminium. To be as cheap as possible. Their advertising mentions sturdy metalwork and taper roller bearings. False advertising at its best. Fraud when claimed over literally decades.

 ~*~

1st March 2025 Dome demolition.

 ~*~

 Saturday 1st. The weather was dry, cool and almost still. My health is no longer an issue. So I started on the demolition of the dome itself. 

 I had already removed the outer building and disposed of the 4.3m  glass fiber dome. My heart problems had brought an end to further demolition work. Now I feel fit enough at 77 to finish the job. After an initial pang of regret and nostalgia I went ahead. Being as safe as I reasonably could.

  First I knocked out all the lower two rows of plywood panels with a 2x4. [50x100] Then I knocked out the lowest crossbars using the same weapon.

 

 

 Collapsing the dome safely meant attaching a long rope to each rib. Pulling on the rope from the safety of the ground snapped each rib in turn. 

 I pulled the shutters off but made sure that the strongest ribs, on each side of the shutters, remained. I wanted those to protect the shed roof next door to the observatory. 

 

 

 Eventually the dome collapsed exactly as anticipated. With very little risk to myself or the shed. The big mounting and pier also remained. To give me shelter and protection had there been an unexpected collapse. I had to go up the internal stepladder each time. To attach the rope each rib. These were the likely danger moments.

 

 

 

 

 

 

 

The shutter ribs were so well attached to their heavy duty drawer slides. That they won't let go. So I have to find a safe way to avoid being crushed by their weight or tension. As I release them from inside the dome. That comes next, after lunch.   

 Meanwhile, the weather has improved to sunshine and 40F/4.4C. Time to start again. The lower observatory room still has a fair amount of useful stuff inside. I shall have to remove it all and protect it from the rain.

 

 

 

 

 15.15 The next image shows the shutter ribs, emergency doors and upper wall cladding have all been removed. I used the bayonet saw on the ribs. 

 The cladding was held by Torx screws. Sadly, the quality of some of those screws was pathetic. The Torx bit just rotated in the hole. Despite being the correct size. The screws were much too soft.

 

 

 

 

 

 

  ~*~