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From Micro Obsy to Dual Pier Observatory - via Hard Work, RSI, Back Ache & Melting Credit Card!


ArmyAirForce

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Due to unexpected rain this morning, I didn't get out until around 1pm today. The plinth planks were added to the rear and shed end of the observatory.

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This corner will all be buried almost up to the top to form the base for the vegetable patch. A top layer of slate will top the weed membrane around the veggie planters and around the back of the observatory. I packed away about 5:30pm, after which I realised I still had the right end to finish down to ground level.

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I don't know how I managed to forget, as I started the afternoon by scraping away at the earth ramp on the right of the observatory. This will provide a grass ramp from the lower lawn to the new upper lawn. I think it was because I wanted to cover the large areas in full planks so I could fill in the smaller areas with the offcuts.

Tomorrow, the forecast is for showers on and off from about 11am, so I may or may not get out to finish the plinth.

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May 30th - I got out to the garden this morning with a weather forecast threatening the wet stuff again starting mid morning. The right end plinth was finished first.

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I also added two boards along the side of the concrete shuttering to tidy the edge up. This will eventually be back-filled with slate around the veggie planters. The builder had put it together with the screws on the inside, so once the concrete was poured, the screws weren't accessible. Two and a bit three meter planks were screwed to the outside of the shuttering and at some point, I'll add a capping strip along the top. I was just about to edge the concrete ramp in front of the shed when the rain came and so the kettle went on!

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It took a while to pass, but eventually it dried up and I unpacked all the tools from the shed again and edged the concrete ramp. Like the plinth planks that were cut to fit the ground level, the ramp took some time. Each piece was marked up, carried back to my workshop for cutting, brought back, edges painted and screwed in place before the next piece was offered up against it for marking the next cut.

When that was done, I started painting a second coat of shed paint on the plinth. I got the front face done, then the rain came again. Using some of the left over planks, I balanced them hanging over the front edge to make an umbrella of sorts to keep the rain off the paint, then retired indoors again. The rain was falling straight down, so the rain covers worked quite well.

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Another coffee or two later, it had dried up again, so I went back out and carried on painting the plinth and shed concrete edging. Then another rain intermission!

It was 3:15pm before I got back out, this time with some of the observatory floor panels, not all of which seem to be 100% square.

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After a bit of jiggling of the positions, I started marking up where the piers would be on the floor. One panel needs a complete hole cutting for the floor to drop down over the pier. The other pier intersects the join between three floor panels.

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While I was measuring up and drawing cut lines, I was very aware of this dark cloud moving in from the West. I'd opened one of the garage doors as an emergency shelter for the floor panels, just in case the rain reached me before I'd finished measuring, but in the end, got everything sorted and the floor back in the workshop ready for cutting and all the tools away before the rain came to end the afternoon.

I'm going to need to do some tidying in the workshop before I can cut the holes as there's tools and other bits of astro-shed everywhere! The holes need cutting, then a trial fit around the piers, before a coat of bitumen paint on the underside. I'm also thinking of cutting a few access hatches in the floor, to allow me to spray weed killer under the floor area. The lack of light and weed membrane should keep things under control, but I want the option to nuke anything that does start growing under there.

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What a great thread and comprehensive documentation of your build. Thanks for taking the time to put it together. It is proving really valuable for me as i am couple of months behind you but working towards a similar 2 pier roll off roof observstory. I am intrigued to know more about how you settled on pier placements and what led you to seemingly offset one from the centreline, or is that just an optical illusion from a couple of your photos?

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1 hour ago, Gogleddgazer said:

.....I am intrigued to know more about how you settled on pier placements......

Thanks. The observatory is aligned with the garden, but not the cardinal points. Staggering the piers brings them both more face on to due South so they don't get in each other's way, while also making a small space behind the deep sky pier for a mini warm room/computer area. You can just see North marked on the circles around each scope in the drawing. The circles also show the sweep of the extremes of each scope. I wanted more space around the solar system scope so I could sit with it. The deep sky scope needed less space and I didn't want to waste the space in the shed.

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Edited by ArmyAirForce
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Makes perfect sense, and really useful food for thought to add to my current mix.  Looking at your cardinal points my obsy alignment wrt North is very similar to yours, albeit the long axis runs about 30 degrees west of North.  I'll have to consider whether staggering them either side of the centre line reaps any real benefits for the more northern one.   

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May 31st - It's been chucking it down with heavy rain most of the day. Fortunately, I had things to do indoors. The morning started with a tidy up and clearing some floor space in the workshop. I needed enough room to get two of the four feet square floor panels laid out. The hole for the deep sky pier was cut in the floor panel with a jigsaw. I may need to add some support under the floor around the edge of the hole.

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At this point in the morning, it hadn't started raining, though the sky was looking threatening again. There was enough time for a quick test fit of the floor over the pier. There's enough clearance to allow for a bit of movement when the floor is screwed down. Eventually I'll make some form of collar to close up the gap between the floor and the pier. I'm thinking of something like a fabric cone, which will seal up the gap to stop bugs etc, but won't transmit vibrations.

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The hole for the solar system pier is split over three, possibly four floor panels. The third panel just needs a slight curve cut out of the edge and it may not even cut into the fourth panel, as it's right on the corner. I've cut the two main arcs but need a trial fit before I make the last cuts. I need a dry day for that.

Once the pier holes were cut, I moved on to the inspection/access hatches. I decided to put two in the front of the floor, one at each side where the height is the greatest and a larger hatch centrally in the rear of the floor. I marked out the cut line along side the nails which hold the floor planks to the shed floor supports.

My circular saw was then set to the depth of the floor planks and I cut across two planks to make the hatch. The arc of the blade couldn't get right into the corner of the cut, so the remains was chain-drilled with my mini drill to break it free. My scalpel was then run along the tongue and groove on each side to free the pieces.

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Cutting along side the nails left some of the floor support exposed so that the hatch had a lip to sit on. The two planks that were removed need their ends tidying up and an anti-warp strip glued and screwed across them to make a solid hatch. These are the two right end floor panels with the solar system pier hole and right side inspection hole.

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The left end hole came next.

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The last hole was in the centre rear panel, but closer to the fore/aft centre line rather than the back. This is because there's a bit more height clearance than right at the back. This hole was also made twice as long to give better access left and right.

The main joists that support the observatory will encroach into these hatches to some degree, but I've tried to minimise it. So long as there's room to get my arm in with a weed killer spray, that's enough space. Cutting the holes was quite an easy job, so should I need to make another hole in the future for any reason, it's simple to do and fill in. The inset image shows the hatch plank sitting on the lip of the floor support.

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The last time I was involved with an observatory that was of the same design was back in 1993 when I was part of the team that built our local societies observatory 

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We counterbalanced the roof section using a wire and pulley system attached to buckets of lead shot.  This made opening and closing the roof a single person operation.

Must say you are making a lot of progress on your build in a short space of time....

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10 hours ago, malc-c said:

The last time I was involved with an observatory that was of the same design was back in 1993 when I was part of the team that built our local societies observatory 

obs8.jpg.95f5b0f362945375fc8264428cfe83b8.jpg

 

We counterbalanced the roof section using a wire and pulley system attached to buckets of lead shot.  This made opening and closing the roof a single person operation.

Must say you are making a lot of progress on your build in a short space of time....

I'm probably wrong but is that the LDAS observatory?

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2 hours ago, Starflyer said:

I'm probably wrong but is that the LDAS observatory?

Correct,  yes  its the LDAS observatory, built over the winter/spring of 1992/3 an opened on 21st August 1993 by the late Iain Nicholson who was our president for several years.

My claim to fame is that I personally laid the foundations single handed.  None of the normal team could get the day off work, so it was down to me to supervise the delivery of the concrete, and I had to use a shovel to move it around with the only good arm as the other was in plaster as I had broken it a few weeks before ! - It would have been a simple job if the driver managed to get the concrete in the footings rather than spilling it over the sides !!

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June 1st - I'm now about six weeks into the project. Not so much directly done on the obsy build today, but all steps along the road to the overall project being completed. The day started with a trip to drop Lynne's car off for a tracking adjustment and then on to nearby B&Q for some bits and pieces both for the garden and observatory. Since Lynne was off work for the week, we wanted to get some work done on the garden. This started by backfilling the veggie patch area to almost finished height. It will be left to settle a while before final levelling, but for now, was left covered by a weed barrier.

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Most of the rest of the day was spent thinning out one of the many laurel hedges around the garden. This stuff grows like mad, something like 12 to 18 inches a year and can quickly get out of control if left unchecked.

Late in the day, Lynne went to pick up little legs from grandma and I turned my attention back to the observatory for a short while. All six floor panels were brought outside for a test fit on the base and around the piers.

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Edited by ArmyAirForce
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I checked on the positions of all the inspection openings and the two smaller ones were fine. The larger opening falls across several floor joists, which I expected, but it does restrict the opening a bit more than I thought. As a result, I think I'll enlarge the hatch by one plank to make it a bit more useful.

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As I suspected the other day, not all the floor panels are exactly square. I'm going to have to jiggle their positions when I come to screw them down, to try and keep the outside edges square. This is particularly important for the ends, as they set the angle of the end walls, which I need to be parallel for the roof runners to perform properly.

The fit around the piers was fine and I just need to take a small piece off the corner of the centre rear floor where the pier hole just cuts into the corner of the panel. I wasn't sure during the original measuring whether this panel would need a small trim or not. It was nice to see the floor down at last and to be able to walk around at observatory height, even if it was just a temporary trial fit. After enlarging the inspection hatch and trimming the corner for the pier, I want to varnish all of the upper surface and then bitumen paint the underside. The varnished top side will help to waterproof the floor until the roof gets made.

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June 2nd - This morning, I started by adding some reinforcing around the pier holes, where the planks had a large overhang.

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The next step was cutting another plank out of the rear inspection hole to enlarge it a bit more. I also nailed and glued some additional narrow strips of wood to the sides of all the holes to give a little more support for the hatches for when they are walked on.

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With that done, all the upper surfaces of the floor received one coat of satin varnish. It was proper solvent based varnish, slightly thinned to help it soak into the wood, but that required a decent drying time. So while that was drying, Lynne and I went out into the garden to thin out the acres of laurel hedging around the property. That took most of the afternoon.

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By late afternoon, the top side varnish had dried enough to turn all the floor panels around and paint the bottom a first coat of bitumen paint. Despite the floor being pre-treated, the bitumen soaked in quite a bit, as can be seen on the panel on the left of the picture. I'd also thinned it a bit to wick into the tongue and groove joints and under the battens that hold it all together. So both the top and bottom sides need a second coat of varnish and bitumen respectively.

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June 6th - I've had a day off and an easy day on the observatory over the last couple of days, mostly through waiting for paint to dry. On Friday and Saturday, the floor received second coats of bitumen and varnish, which then had lengthy drying times. The rest of Friday and Saturday was spent gardening, trimming back more laurel hedge! On Sunday, I took my Jeep out to a Jubilee party.

Today, I got back to work, but with slow progress due to the nature of the odds and ends I'm working on. Rather then wressle trying to unwarp the planks cut out for the hatches, I found a piece of 3/8 inch plywood that was big enough to make the three hatches from.

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All three had a small finger hole cut into the end to help them to be lifted out of the floor. They were given several coats of varnish, the first two of which rapidly soaked into the plywood. The bottom side still needs to be painted in bitumen, but I can't do that until the varnish has fully cured.

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Edited by ArmyAirForce
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While the hatches were drying from their first coats, I also painted the floor joiners in bitumen. These six pieces are used to help tie the six individual floor panels together. One end will be screwed to the panels before laying, giving a lip to rest the next panel on to.

In the original shed instructions, it wanted the floor panels screwed together into one large panel first. Fine for a normal shed sitting on a concrete or gravel base, but impractical for the observatory to lift a 12 x 8 bendy floor over the piers! There's no real need anyway, as my floor can be screwed down to my floor joist framework to form a strong base for the shed.

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To finish the day, I infilled all the end gaps in the shed floor structure. These four pieces across the outer end of each floor panel, close up the gaps between the shed floor structure and my floor joists, stopping small animals and weather from entering the gap. Each was cut to fit as every gap was slightly different and all had the ends and top painted in bitumen before squeezing into place. The remainder was then also painted. They're all a tight fit, but I'll add some screws through the top tomorrow to secure them.

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June 7th - First thing this morning, I added two screws to each of the infill pieces of wood on the floor panels to secure them. After that, the floor hatches were painted in bitumen on the underside.

With those moved out of the way to dry, I started working on the front wall of the observatory. One plain panel and the door panel were cut down in height to match the end walls. They were then clamped together in order to attach a new top rail to stiffen the structure. Each panel is four feet wide, making the front wall twelve feet long with two joints and a big opening.

The top rail makes the door height a little under four and a half feet tall. I'm used to ducking through the small door of my old observatory, so the lower than normal height doesn't bother me and is necessary to give strength to the wall and the low wall height that I wanted.

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An eight feet length of two inch square timber was centred over the door opening, allowing it to extend half way across each adjacent panel. This braces the joint between each of the three front wall panels. From each end, a 12 inch section was cut to half its thickness to form an overlap for the next piece of two inch square top rail, which would extend to the end of the wall.

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The first two wall panels were supported upright so that the top rail could be glued, clamped and screwed in place. At eight feet long so far, it took up quite a bit of workshop space, both lying down and standing up. I'm not sure whether there's room to attach the third panel in the workshop and still get around it to work on it ( or for that matter, store it until needed ). I may have to do a trial fit and cut the remaining piece of top rail for the left end, but leave it separate until the walls are assembled at the observatory site.

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Around mid afternoon, the third of the front panels was lifted from the pile, laid on the floor and cut down in height to match the other panels. The uprights were cut two inches shorter, ready for the top rail, but that's as far as I got. I needed the clamps that were still holding the right side together while the glue dried, so left it there for the day.

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June 8th - I didn't get started until after lunch today. The third panel that makes up the front wall, was attached today along with the rest of the top rail.

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I got some paint yesterday and this afternoon, started painting a first coat on one end panel. The other end was moved out into the corridor as I was running out of work space.

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The paint was a light colour to try to reduce heat absorbtion in the building. However, the light colour made the shed nailgun holes really stand out like it was a dartboard. As a result, I mixed up some filler from wood filler, waterproof PVA glue and fine wood dust, then filled every nail hole in both ends and the front wall.

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There's around 80 holes in each four foot panel, so it took some time to fill the holes in the seven assembled panels. There were also some knot holes and areas of course or open grain that were given some filler too. That all needs to cure before being given a light sand before it can be painted again.

Tomorrow morning, I've got a guy coming to remove six tree stumps around the observatory and new lawn area, so I've got a little clearing of some old weed membrane in the morning.

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June 9th - The tree stump removal guy came this morning and ground out six stumps, including the remains of the big tree just behind the observatory. While he was busy, a friend turned up in his World War 2 truck. He's been having trouble with the carb mixture for the last year and this morning was its first run out, seemingly sorted. We chatted for quite a while so I didn't really get anything done until after lunch.

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So after lunch, I did some sanding of the filler from yesterday, but several of the filled holes had sunk as the filler was curing, so I went back over many of the holes with more filler. As well as for cosmetic appearance, I wanted the holes plugged to keep the weather out of the nail holes. That was me done for the day on the observatory.

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While the filler was drying, I got the Jeep trailer out as I needed to swap the 24 volt bulbs for when the Jeep is towing it, for the new 6 volt LEDs so it could be pulled by my Dodge Weapons Carrier. By the time I packed away, the day was over.

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June 9th ( evening ) - I got rather depressed on Thursday evening. During the day, I'd noticed a Durham council van parked at various points in the street. By late evening, I realised what they'd been doing - LED street lights. There's one immediately in front of the house which illuminates the whole front of the property like a high security prison. However, it's the one a little further down the road that's the real problem. That illuminates the whole side of the house and the back garden. This is the view from next to the observatory ( phone pic on night settings ).

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This one is from further up the garden, but taken with a DSLR. It's a 30 second exposure, ISO 100 and f14. It's piercingly bright to the naked eye and casts shadows like the mid day sun.

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