 I'm in the process of building my dream backyard observatory. It's somehow been two months since my last update and all I have to show for it is a floor. But I think it's a very nice floor. I'm proud of it. And a lot more goes into a floor than I realized. I did make a number of mistakes when building it that I had to correct along the way. So I'm hoping you can learn from those if you decide to build your own observatory like this. For anyone who didn't see part one, I'll of course link it in the video description. But as a recap, since it's been two months, since I last gave you an update on this, in that video I covered how I picked the location in my yard. I showed demolishing an old shed that was in the way. I showed staking out the footprint of the building and finally digging and making the telescope piers which I made out of poured concrete into sonotubes which are just cardboard tubes. And then I pushed metal pure plates that were attached to J bolts into the wet concrete at the top to finish those off. A mystery from the first video that a number of you weighed in on was what was that metal object that I pulled from deep in the ground when digging the holes? And the two guesses that I saw the most often in the YouTube comments were a horse bridle which I could definitely see the resemblance based on pictures that I found online of excavated horse bridles. And the other main guess but a lot of people were pretty sure about this was a bolt snap that you often see associated with dog leashes. So I let all the hardened dirt dissolve off by soaking it in warm water and after that it looks like this. So I think the people who guessed bolt snap were correct. And speaking of digging holes I thought I did a lot of digging for the first video but I was not really mentally prepared for just how much digging the floor would require. It started with digging eight 16 inch diameter holes to a depth below my local frost line which where I live is around four feet deep. And I ran into many big rocks. I found that if they were pretty close to the surface like two feet or shallower it wasn't a big deal. I could leverage them up and get them out of there. But if they were really, really deep I had no means of getting them up. So what I had to do in one case instead was I dug a cavity to the side of the main hole and pushed the rock over into the cavity and then sort of filled that up so that the sauna tube could go where it's supposed to go. Now my first big mistake is in the digging of these holes. I very carefully measured many times where I should dig them in terms of their position. And that was all correct in terms of surface measurements but then I was relying on my eyes to determine that I was digging straight down. And in retrospect that was a big mistake because when I started actually putting in the tubes and remeasuring I realized all my tubes were at funny angles because none of my holes were straight to begin with. So even if I had started digging at the right spot where the top of the tube actually ended up was now wrong because the hole wasn't straight. And this meant that I spent a lot of time trying to fix this. Scrape the sides trying to straighten them out but then when I scraped the sides I'd run into a big rock and I have to dig that out of there and it became a whole thing. And while this was happening I kept checking for level and my tubes were getting more and more deformed because I was putting them in and out of the holes and rechecking level and so it wasn't a good situation. If I were to do this all over I would have started leveling my holes as I dug them using a long eye beam level, a bubble level in a vertical position along the side of the hole. This was not the end of my problems with these holes and tubes, only the start. I had thought that there is no way I'm gonna be able to dig all the holes to exactly the correct depth given the slope of the yard to get all the tops of the tubes level. So I thought, okay, I'm gonna be a little creative here. I'll not care about where the actual top of the tube is I'll just fill them all to the same level. I'll use a laser and then I'll drill out where the laser hits the tube. And then because I put the laser on top of a piece of wood I'm gonna use that differential from the laser to the top of the tube and mark them appropriately. I hope that makes sense. It's a little bit convoluted. And this wacky system may have actually worked out if I could have been confident that the laser beam itself was level. But to do that I should have bought a self-leveling laser. What I actually got was a laser measure because I thought, oh, well this will be sort of cleaning two birds with one stone. I thought it'd be helpful for double checking measurements and also a level laser. But it wasn't a level laser, it didn't serve this purpose. I just didn't consider that the laser beam coming out of that laser measure could have been coming out at a small angle. And that meant all of my peers were off by that angle and that means that the further away a peer was from the origin of the laser the bigger error that I had at the end. So in the end, the difference between my highest structural peer for the building and my lowest was a whopping two inches or five centimeters which is way too much to make up with just like shims or something like that. So what I decided to do to fix this big mistake was a second pour of concrete so that the peers that were too short could get raised up a little bit and be level with the tallest peers. But to make sure that that second pour was structurally sound, I wanted to add rebar pieces. So I used a rotary hammer to drill holes into each peer that needed fixing, epoxying in rebar, which is just metal with special epoxy that you can get for this purpose. And then I covered the surface with some bonding agent and then did a second pour with duct taped on sauna tubes. I don't have footage of all of this far because I think I was so frustrated I wasn't filming. But anyways, this time I used a, instead of using a laser I used a piece of lumber, straight dimensional lumber that was long enough to span the whole footprint of the building. And then I used a long I-beam level on top of that and I continually checked level which in retrospect is what I think I should have done the first time even if it meant taking time to like shave off the top of the sauna tubes a little by little with them already in the ground. But in any case, the fix for this structural peers thing really slowed me down. I think between figuring out what I should do, getting the materials, doing the work, the fix took like between seven or 10 days. But in the end it did work and I had leveled structural peers to go on to the next step. And the next step, as you can see here was removing all the organic matter from the footprint of the building. So, and then putting down black plastic, replacing all of that organic matter, all that soil that I took out with crushed stone. And as architect Timothy Emerson said in my video with him the purpose of this step is mostly to stop the ground below the structure from holding moisture and moving that moisture up into your building. But also animals critters aren't gonna wanna burrow into the crushed stone. So it makes it a little less hospitable for them to come under your building and wreak any havoc there. I naively thought that this whole process of removing the soil, putting down the plastic, putting in the stone would take a day. It actually took me four or five days. I calculated that I removed over two tons of sod and soil and then replaced that with about an equal amount of crushed stone. So it was definitely my least favorite part so far. I just found it sort of tedious. But my reward when I finished that was I could finally move on to working with wood and hardware, which I really preferred. So the first step in this stage was drilling holes in the center of each structural pier with a rotary hammer. I know where I put the rebar for that fix. So that wasn't a problem. When you do this, when you drill with a rotary hammer into concrete, you wanna wear all the appropriate gear like a respirator, safety glasses and gloves because it's a messy sort of situation and you don't wanna breathe in that concrete dust. And it creates a lot of dust, which I removed with a combination of compressed air and a shop vacuum that cleaned out the holes. And then I could hammer in a concrete anchor to attach to these galvanized post bases to the concrete structural piers. These post bases are made by Simpson Strongtie and it's a really neat system I think. It keeps both the lumber up and away from moisture that could contribute to rot and it's a way to anchor your buildings so that you don't have to use ground anchors. Now these post bases are three and a half inches wide so to make a floor beam that fills the post base, I used two treated two by sixes and then a sandwiched piece of half inch treated plywood that I cut to size of the two by sixes. And then that whole thing was nailed together to make my floor beam and then the floor beam was nailed into the post bases. Whenever I was just nailing wood together, I used this nail gun which is designed for framing and I used strips of nails, these three and a quarter inch galvanized nails. I found that the building code said that you need to put in three of these for each two by six connection so that's what I did. Whenever I was using Simpson Strongtie hardware, I used the recommended connectors which in the case of these post bases was pretty annoying because it said you need eight three and a half inch galvanized nails per base. And I just found this really difficult to drive in by hand. I think it took me a few hours just to nail all of those in and my wrist was pretty tired by the end. But with that done, I rechecked level in both directions and I was happy that everything really looked good in terms of these beams. At this point, I remembered that I had wanted to smooth out the rough edges of my telescope peers. I thought this would be a good time to do it. So I used an angle grinder and a diamond cup wheel. And again, you definitely want to wear all the protective gear if you do anything like this where you're making concrete dust. It was really quick though and it worked really well and it wasn't just for aesthetics. I was also thinking about cables rubbing on that rough edge and getting worn out. So what I did is I took all the rough edges of the concrete peers and I ground them into this sort of smooth chamfered edge. So next I started looking through my two by sixes and these are gonna form the floor joists. And I marked them so that the crowns all went up. And what that means a crown is that any piece of long lumber is gonna have a slight bow to it. And you want that bow going in the same direction for all your joists. The common wisdom is you put that crown or the bow, the warping of the wood up so that the highest point of the floor will be in the middle. So that's what I did. I then cut these all to size using a chop saw or a miter saw is also called. That's not strictly necessary. You could definitely use a circular saw but the chop saw is very nice for making straight cuts in boards. If you only wanna get one saw though for a project like this, you would wanna get the circular saw because you'll need it for cutting other things like sheeting where you can't really use the miter saw. Anyways, I then laid out my finished joists onto the beams and I figured out how I wanted to space them. The typical spacing for floor joists in a situation like this would be 16 inches on center but since I have these telescope piers in the way, mine is a little bit wonkier than that. The most that any joist is spaced is 16 inches but many of them ended up much closer together than that. I figured the floor would be stronger with more joists than necessary. I didn't wanna sort of skimp on the joists. I also doubled up the joists around the telescope pier opening. I then marked these where these joists should go on the joist headers which is sort of the front and the back of the floor. And if you don't have a speed square which is this little blue plastic thing I'm using, you should get one for this. It's very handy for marking lumber accurately. I then nailed all the joists to the joist headers. Again, with that framing nail gun and then again checked for level. It was pretty close but I did use a few little composite shims at this point to try to perfect the leveling and then I also started checking for square which you do by measuring the diagonal of the structure you now have and in my case with a 10 by 14 building according to the Pythagorean theorem it should be just under 206.5 inches in the diagonal which I was able to achieve just by sort of gently kicking the corners a little bit until it all squared up and measured correctly. I then toenailed the joists to the beams which just means shooting nails in at an angle and screwed on hurricane ties. These are again Simpson strong tie brand and I am using the screws recommended. I went with screws here and an impact driver because I didn't want to nail in all of the recommended nails by hand. I felt driving in the screws would be faster than driving in nails by hand. The reason I'm not using screws for everything in this construction comes down to both speed. The framing nailer is definitely faster than an impact driver but also cost. I can get 2,000 appropriate nails for framing for about 90 bucks. To get that many appropriate structural screws, 2,000 I calculated it would be over $600. So over six times as much and all of these little costs add up really fast with a building observatory. Next I wanted to do some prep work for electrical in the building. I don't have the money to finish electrical right at this moment. So I'll save up for it and get to it in the spring. But while I have the subfloor exposed like this it's a good time to run plastic conduit to the piers from the edge of the building where the electrical box is gonna be. And so I ran a string through the conduit to make it easier to fish electrical wires through later to get a string through a piece of conduit. You can tie a little piece of plastic to the end of the string and then use a shop vac to suck it through the conduit. I used a combo of a stubby wood auger bit and then a longer spade bit to drill the holes through the joist for the conduit. The spade bit was just necessary for the double joist to get through those. I then added lots of what's called blocking, I guess. This took a full day. I doubled up the blocking around the opening for the telescope piers, which I read is something you wanna do whenever you have an opening in your floor like this. And then I did a single line of blocking wherever the plywood sheets were gonna meet. So blocking just means, you know, as you can see, just little blocks of wood in between the joist that you toenail in. I would highly recommend carefully measuring for the blocking because due to the way that wood warps, I didn't have any two pieces of blocking that were exactly the same width. You want this pretty precise, I think, because if you're not, you're either gonna leave gaps or you're gonna try to force the blocking in. You want it just to sort of go in fairly effortlessly. So the blocking was toenailed into the joist and with that done, I was then ready to put on the sheeting, which, and I was using three-quarter inch treated plywood. And I had a little bit of trouble with this three-quarter inch plywood sheeting. It was left out of my yard in a stack, you know, for a week or something. And there was, it was covered, but there was moisture, of course. And so then when I was taking it out, I noticed all this gross black and white mold-like stuff. I read about it and it's like, that's normal. It's just, it's on the surface only. And what I was read is that you can just sort of scrub it off with dishwashing liquid and water and rub it off and let it dry, and then it should be fine. It's not gonna actually harm the wood because the wood is treated. So it's just a surface mold. So anyways, I dealt with that. You can see my kid in here was pretty interested in that process. After it dried, I then laid down a bead of liquid nails subfloor glue and this helps prevent squeaks. And then I started, you know, actually laying the plywood down and then nailing it into all of the joists and blocking. I left about a 1 1⁄8 inch gap between each sheet. So if it does get wet and expands, it will have somewhere to expand into. I used a chalk line at the end and a circular saw to cut off the excess sheeting. And then when it came time to lay down the second row of plywood, I had to cut out the openings for the telescope here. And I got so preoccupied with that that I made another mistake. I forgot to stagger the sheets, which I had planned to do. You're not really supposed to have four sheets meeting up like this. You're supposed to stagger them, which I did remember to do in the back for the final two strips of plywood here. It looks like this, but that should have been also repeated in the front. I didn't fix this mistake because I didn't think it was a huge deal. Maybe I'm wrong, but in any case, I then nailed the plywood down on every joist all the way, you know, up and down the structure, spacing the nails about a foot apart. At this point, all that was left was the openings for the telescope here. So to do those, I made templates out of cardboard because I didn't trust myself to get those right without messing around first with a template. Once I got that template how I wanted it, I used my circular saw to make the straight cuts and a little handheld router thing to make the circular cuts, which was a little bit tough with this thick plywood. So they aren't perfect by any means, but good enough for my purposes. Eventually, I wanna have outlets wired into the floor at each pier. So I marked where those would go when I get to the electrical work. At this point, these pieces that I made are just sitting on the framing here around the piers. I might not nail them in. I don't think it's really necessary. I do wanna find some weather stripping that will fill this gap though, just to prevent bugs and things from getting up into the observatory. But, you know, I don't wanna transmit any vibrations to the pier with whatever I fill in there. And speaking of vibrations, I did a little isolation test here where I balanced a speed square on one of these bolts, so very precariously balanced it. And then I jumped up and down all around to see if it would fall off and it didn't move at all. So that was very promising. I don't think there's any vibration from the floor that's getting transmitted to the isolated telescope piers. Another test I did was I put my longest telescope on one of the piers and I checked out a number of things. I want my roof to be able to close even with the scope in the normal parked home position and I have almost a foot of clearance there. So I could get an even longer scope in the future and it would still be fine in terms of closing with the telescope in any position. My mistake with the structural piers where I had to do the second pour, it did put my floor about two and a half inches maybe higher than I originally planned, but I still had plenty of clearance with the escar 130 in terms of the floor. I did want the whole building pretty high above the ground to begin with because I had a flooding scare this summer and I wanted to make my observatory as flood proof as possible. So if there was a lot of ground water, it wouldn't even touch any lumber or anything like that. So in the end, it has taken me longer than I expected to get to this point and I now need to actually take a little break from building to take care of some various things, but I've come to peace with the fact that I will be building in the snow. I'm fine with that, I'm originally from Minnesota. We've actually had our first snow up here in New Hampshire already so I was able to test tarping up the floor and that seemed to work quite well for keeping the floor dry. So next up for me in terms of building is I'll be building the trusses, the structure for the roof and then building the walls and then the extension and then the roll-off roof and the list goes on from there. Eventually, trim work and electrical, maybe automation. My thinking is to just keep steadily working on the observatory until it's at least functional and then maybe I'll take a break and think about next steps. And I really actually have to do it that way because I've already exhausted my initial budget for this project and so then I'll save up some more for the next sort of parts. I'm thinking electrical will take a pretty big chunk and then automation would also take up a pretty big chunk. I really want to express so much gratitude here to my Patreon community. Since the start of the year, I've been doing Nebula Photos full-time which is a bit of a juggling act but being able to count on the generous support from my Patreon members is what has allowed me to pursue this observatory build which as you just saw takes up a lot of time that I could be using, making videos or doing other things but I hope in the end it's gonna allow me to be even more productive as an astrophotography educator slash YouTuber. So I think it'll all be worth all the time I've put into it. So anyways, my Patreon support really means the world to me and if you decide to join, there are some perks associated with it. You get direct messaging support with me so you can use the Patreon website or the app and just type in a message and I'll get back to you. We also do a live monthly Zoom call for Q&A and various discussions with the whole Patreon community and there's plenty more discussions at all hours of the day over on my Discord server which if you join the Patreon then you get many Patreon-only channels on Discord including our monthly imaging challenge. So I try to make it worth it for you and it starts at just $1 per month for the basics which gets all the things I just mentioned but then there are different tiers with added perks like it's $7 a month and up, you get ad-free videos. So that's it for this one. If you're in the U.S. I hope you're having a nice Thanksgiving holiday. Till next time, this has been Nico Carver. Clear skies.