ArmyAirForce

After the heavy rain of yesterday, today was a hot day - probably too hot for hard work! I started off back filling the outside of the blockwork with concrete. Due to the amount needed, I'm not going to back fill the whole height with concrete. I've filled it to half way up the second layer of blockwork and that took 80Kg of concrete! The rest will be back filled with a slury of the soil and clay we dug out, possibly with a little cement mixed in. Knowing how hard the clay was to dig out, it will set hard and the block isn't going anywhere. Another 170Kg was poured inside the blockwork, to bring it up to the top of the bricks. This now brings the foundation total weight to 430Kg!! EDIT - Actually, there was another bag and a half put in the bottom of the hole to set the blockwork on, so there's another 30Kg, bring the total to 460Kg. I realised I was going to be short on concrete and nipped out for another twelve bags after the first pier was done. I should have enough now to do the second foundation and both piers. After getting back, I mixed up another three and a half bags to back fill around the outside of the second pier foundation. I couldn't pour it without more wooden crosses to support the rebars, so have left that until tomorrow when I can reuse the first set. Hopefully I can get that and the first pier poured. It was hot work and even with the mixer doing the hard work, I was melting by the end of packing away.

I do more imaging than visual observing, but when doing solar, I try and set up first thing in the morning, to image around mid morning. By that time, the Sun has risen moderately high in the sky, but before the real heat of the day has built up and before heat is being radiated back up to any significant amount. Mid afternoon is worst and by evening, while thermal currents may be decreasing, so is the altitude of the Sun. So mid morning is always my preference.

No, just cut it on a small scroll saw and used double sided tape to hold the filter film to the wood.

I've got two, both made from plywood. One with ND5 filter and a red painted ND3.8 for imaging only. They attach to the end of the scope with velcro.

Allowing for the height of the pier adapter and mount, it should bring the telescopes into the roof cavity space. This means that if I turn either of them to the North West ( left in this picture ), they should be looking up the slope of the roof runner line as their lowest viewing position. There's little point in having the observatory wall any lower on this side, as there's a small woodland on the other side of the garden that would obstruct the view. If there's something really interesting going to happen in the North West, I'll take a mount off the pier and set a tripod up on the lawn, higher up the garden. The weather forecast is for rain and thunderstorms for the next two days, so I'm unlikely to get the concrete foundations or piers poured just yet. I want to pour the piers as soon as possible after the foundation will support them, so the concrete gets a good chemical bond in addition to having the rebars providing support.

It didn't take long to lay the bricks, after which, the joists were all screwed together. As before, this is just a temporary measure for checking stuff. I'll probably be evening out the earth height around the piers once they are poured, so the weed membrane has a nice even surface to lay over. I'll want the joists out of the way again for the concrete pouring and digging. My daughter gave me a hand out with one of the observatory end panels to check the pier heights against the rolling roof height. The piers were standing about an inch high, due to sitting on planks over the foundation holes. The pier adapters and mounts add another 22 inches on top of the pier.

Today, the floor joists were carried out once again to check on the height between floor level and the top of the pier foundations. I needed about 12 inches. The deepsky pier was pretty much spot on with about 10 inches to the top of the joist, plus another 2 inches of the shed floor. The solar system pier was a bit low by around a couple of inches. The easiest way to solve this was to add a layer of block paving bricks. So off to B&Q for eight bricks and a bag of sand and then back home to get them laid. This would allow the foundation concrete to be filled flush with the top, so the pier tube would start at the correct height.

This morning, the eight extra rebars I ordered, turned up in the post. I wasn't expecting them until Monday. Unlike the bars from B&Q which were varnished, these weren't and were covered in light surface rust. I didn't want to stick them in my concrete going rusty, so cleaned them all up with a rotary wire brush in the pillar drill and then painted them in hammerite. Since I'm almost in a position to pour the piers, I made these wooden supports to hold the rebars straight in the hole while the concrete is poured. The lower cross holds the bars in the base of the pier while the second cross supports the bottom of the rebars that extend up into the pier. The cross also fits the top of the pier tube, so when I come to pour that, I can also keep the bars straight. I only need one cross in the top of the tube as there's only four bars that extend up the tube.

Even though I laid the second pier foundation yesterday evening, it was firm by late morning today. I hadn't expected it to have cured, but it gave me the opportunity to get the blockwork in for the second pier. Another 90 minutes passed and the second one was done. The blockwork needs to fully dry before I can pour the concrete inside and out, but I also need to wait for some more rebar coming in the post. Local stores were all out of stock, so I had to go online. The new rebars will be set into the top of the foundation block, then extend up into the pier. The existing bars will extend six to eight inches into the bottom of the pier. The foundation concrete will need to set enough to support the upper rebars and also be firm enough to support the weight of the concrete when the pier is poured. This view of the two foundations is looking approximately South. The way the piers are staggered gives them both a good view South and gives me my small warm room space in the left foreground. The right pier will be for solar system targets while the left will be for deep sky.

This morning, I went out to work on the piers. The concrete foundation for the first had been dry a few days, so I started laying the blockwork. It was hard work laying the blocks so deep in the hole and I had to climb into the hole for the first layer, being careful not to stab myself on the rebars. Layer two was easier, but still quite a reach to lower the blocks in place without following them into the hole! It took about 90 minutes to get the first twelve blocks in place. The first 180Kg of the foundation.

The ground was moderately dry after 6pm, so I went back out and mixed up the concrete for the base of pier 2 and left it covered with some plywood in case of further rain. However it is meant to be dry and clear all night. After I cleaned up and put the tools away, I did a minute of astronomy with my phone, with the two piers in the foreground and the 77% illuminated, 11 day old Moon at 35 degrees altitude in the South East.

I got the other side of the legs and joists painted this morning, then went out to carry on digging. I got to the bottom of the second hole at seven wheelbarrow loads, plus the huge pile of rocks. I just got some hardcore into the bottom of the hole when the rain came. It's stopped now, but I'm not keen on kneeling/lying on wet ground, trying to smooth out concrete at the bottom of a two and a half feet deep hole. My daughter will be home from school soon anyway, so I've got my feet up and coffee in hand! I'll have to photograph the huge spoil heap that the observatory has created! ( EDIT - picture added ). This will go into leveling the land beyond the observatory where we plan a second lawn and a 1/1 scale railway garden feature! The spoil heap is 23 feet long, 2 to 3 feet high and about 5 feet wide!

I bought a single stack Lunt LS50THa B600 in 2015. The pressure tuner failed fairly quickly and the whole scope was replaced by Lunt. I use a ZWO ASI120MM-S camera on it with a home made tilt adapter to prevent Newton Rings. I use it at the native 350mm focal length and with a x2 barlow giving 700mm. I'm always wanting more detail, but can't justify the cost to myself. Here's a selection of pictures between 2015 and now. The full disc just fits on the ASI120MM-S sensor.

By the time the school pick up run was due, the hole was almost at full depth, but it fought me all the way. Five full wheel barrows of heavy clay soil came out of the hole, along with this pile of bricks, concrete and stone. You can see a brick on top of the pile to give scale to the lumps! I could barely lift the trowel by the end of the day. Below is the second hole, almost complete. My placing of the hole, dictated by the nearby tree stump, was fortunate. As I dug down, one edge of my hole fell exactly in line with one of the brick walls from the old air raid shelter ( inset ). These bricks are very hard and the wall is double brick thickness. I had to smash one wall out when the conifer hedge was cut down along side the garage concrete hardstand. This was so the tree felling team didn't damage their stump removal machine on the bricks. It was a nightmare to smash the bricks out and I broke one hammer and damaged another getting them out! So I'm really fortunate the edge of my hole was flush with this brickwork.

I could do with having the frame assembled outside when I pour the foundation for the pier. The top of the foundation height is related to the floor height, which in turn sets the pier height. So I decided I needed the joists and legs waterproofing. So this morning, I spent 3 hours painting the original corner legs and the new intermediate legs, then turned my attention to the main joists. All the intermediate joists will need painting too, plus the underside of the shed floor, but I can't do any of that until the piers are in. After a quick lunch, I set to work digging the second pier foundation hole. All I can say is that I'm pleased I didnt dig this one first; otherwise, my observatory may have only had one pier!! It was very hard going, with lots of smaller one to two inch stones or bits of brick in the upper layers. This meant my spade couldn't dig through it and I had to resort to a small gardening trowel, which due to its more pointed end, could cut between and push passed all these small stones. As I dug further, I started to find larger bricks and what I thought was a complete brick at first, turned out to be a five to six inch slab of very hard concrete, wedged under and over more bricks. I had to mine under and around it before belting it with a small sledge hammer, breaking it up into four main chunks which still put up a fight to remove! The further I went down, the more large stones and bricks I found. My dodgy elbow was killing me.

The new mixer made short work of mixing the concrete for the foundation at the bottom of the hole. This was just a thin layer to form a flat base for the next step. Three layers of high density concrete blocks will be built up in a square with a hole down the centre. Blocks are much cheaper per kilogram than concrete to mix. The centre of this square will be filled with more concrete, in addition to the space between the outside of the blocks and the hole in the earth. Four re-bars are fitted up the centre of the square and a further four will extend up to the top of the pier tube.

May 9th, was mostly spent digging and digging.....and digging! The first pier hole was extended in width to match the strings plotted out the day before and then I started digging down and down. Since the slope of the earth drops away to the front of the pier, I wanted to go down a decent distance so the foundation was supported on all sides. The hole was about 2 feet square and a tight space to dig in once I got too low to reach from the outside.

A closer view of the observatory, again looking approximately South South West. Slightly out of work order for today, the other end panel was trimmed and the roof runner screwed in place this morning. The tongue and groove side was planed down to the runner and sanded flush. Since it was a nice day, that's when I decided to go out to the garden and move the job along out there.

Lynne had been wondering how much of the garden would be blocked by the observatory when viewed from nearer the house. She held one of the end walls in place while I took a picture from about half way to the house. Once the garden shed is pulled forwards onto the new concrete, half of the observatory will be hidden anyway. This was one of the reasons for the low height of the observatory. Another was that it meant the piers didn't need to be so tall and the whole thing is just more hidden in the garden by the hedges. This view is looking approximately South South West. Back down at the build site, Lynne supports the end wall. Her eye line is around the height of the top of the roll off roof. I don't recall if I've mentioned it before, but due to the floor height above the lawn, I'm planning on some fold out steps in the doorway. When not in use, the steps will fold away inside the observatory and leave the lawn unobstructed for mowing.

Another busy day under a surprisingly hot sun. The outer floor joists were refitted today and the diagonals carefully measured to get the base as square as possible. Once the position was set, I drilled the bolt holes into the footings for the rear corner leg brackets. The brackets were then bolted down finger tight and the floor joists screwed together. Again, this was just a temporary measure. Once all the piers are done, I want to lay a weed membrane down over the footings and then bolt the brackets down onto them. With the floor in position, the other six legs were marked up and cut to length. Their mounting plates aren't yet bolted down. I'll do that when I'm doing the weed membrane. With the frame supported and secure, I marked out the edges of the pier foundations on the timber frame and knocked some small panel pins in. String was then stretched across the pins, end to end and front to rear to give me the pier position. Small stakes were then hammered into the ground where the string crossed to mark the area to dig. Both piers were marked out with string across the frame and after staking out the corners, the string was removed and refitted around the staked out corners. This will let me dig out the foundations without tripping over strings suspended above ground.

Thanks to a chance spotting of an advert in the "Latest Posts" section of the SGL homepage, I met up with @bilbo this morning and bought the second NEQ6 mount needed for my observatory. My original NEQ6 Pro was bought in 2012, while the one I've just got is the newer, green trimmed model. I'm not sure when that version was released. This one is about two years old and in excellent condition. I can't wait to get them both installed. I'm just about to get changed, head to the workshop and start modifying the other shed end panel.

The runner timber was screwed down into the wall uprights and the tongue and groove was screwed from the outside into the runner, tying it all together. The excess T&G that extended above the runner was then chisled away to almost flush and needs a final sand to bring it level. I must buy myself a new small plane before the other pieces are done. My old small razor plane died a while back and was never replaced. The overhanging end of the runner still needs trimming off. I'd just got the runner screwed in place when it was time for the school pickup, so chiseled the T&G when I got back. That was it for the day. The first side is done. Yesterday, all the end grain on the legs and floor joists were painted with several coats of dilute waterproof PVA glue, allowing it to soak deep into the wood and help seal it. The only other job from today was to paint the four legs in bitumen paint. While it is treated wood anyway, the PVA and bitumen paint will help to keep moisture out. I'll be doing the underside of the floor before fitting too.

This morning, after a B&Q trip for some timber, I began to cut down the end panels of the observatory. The uprights were cut through along the new sliding roof line. The panels were then separated and the tongue and groove cut following the slope, but slightly over size. The two panels were then screwed back together and a 2 inch square roof runner clamped in place. This single long piece will add rigidity to the upper part of the end panel, formerly provided by the roof. Once the shed is fitted in place, I'll extend the runner with a second piece of timber to support the roof when open. An aluminium angle will be screwed on top of this wooden runner for the roof wheels to roll on.

The builders finished the concreting in the garden yesterday. I now need to give it a month to fully cure before I put any significant weight on it. The square in the foreground, replaces some existing concrete that was rather thin and cracking up. The shed will be moved and my trailer will tuck in here, along side the garage and under a planned trailerport. The shed will be moving forwards in line with the garage front and also moving towards the camera to the edge of the new concrete. This leaves space for the trailer beside the garage. A raised bed veggie patch will be built on the soil in the foreground, between the shed and the observatory.

This end panel goes closest to the garden shed and garage and faces East North East. The aluminium rulers mark the roof runner position, while the two pieces of timber at the top of the picture show the top of the roof. The sides of the roof panels will be about 12 inches tall. The green foam tube is a light shield that goes over the mirror end of my 200PDS scope, stopping stray light from getting in around the mirror. It is slightly larger than the scope size, but is a good representation for the position. The front wall of the roof section will open upwards to allow the roof to slide down the tracks and clear the scopes. The clearance between the roof and scope was similar on my last observatory. It keeps the walls as high as possible to act as a wind break while still giving the scope the best possible view all around. It's been a bit of a challenge working out the height of the scope, the pier, the observatory walls and the pier foundation height in relation to the floor and ground height - all being interconnected.