Hi,

I just broke ground on a 3.5 meter diameter domed observatory. I'm documenting the project as it progresses. Anyone interested can find some details on my web pages (address in signature or use the below link). So far I've poured the pier and started staking out the base. I hope to have the base framed in this weekend. I will update my web page as constuction progresses.

 http://www.astronomyasylum.com/observatory.html

Bill

You are a tease Bill!  I can't wait to see what your dome is constructed of as well as the design. Good luck on your project!

L

Looks like your off to a great start, can't wait to see the finished product.

Update: construction is going well. The pier and framing are complete. Whats left is installing the floor, constructing the dome, running utility lines, and adding an exterior covering to the base and dome. I plan to start next on the dome base ring and then the ribs. I will wait with installing the floor until the dome is ready for installation; this is because summers can be very wet in Denmark and I want to prevent water damage to the flooring material.

Thanks for the comments I have received so far. I have not posted any details about my dome skeleton because I am using and modifying a material designed for a completely different application. I have made some small prototype ribs that I am very pleased with. I want to put the entire dome skeleton together at full scale and verify that the material works before posting details. This is just to make sure that the design and materials work before I pass the details on to others.

 Bill

Another update: all framing is complete and the dome base ring is finished. There has been some delay due to rain and winds. Today I test fit the first of the two central arches and it looks OK. I need to play a bit with the arch curvature to get the structure within code: maximum headroom vs. being under 2.5 m tall so I don't need a local building permit. This will probably cause me to play around with the dome curvature a bit, perhaps using something slightly less than a perfect half of a spherical dome, but it should not be too noticible. The first central arch basically looks good, so I'm hoping to get the second arch fabricated this week-weather permitting.

Bill

Looks really good. Cant wait to see the finished product. Did tou dig the trench for the electrical and cables yet? Just a thought, but I amk sure you know this!

Good Luck

Steve

That looks great!  It must be a fun project. Seeing the progression is amazing.  Well done.

                                                                                                                   cjw

Another update: The dome frame is complete and I am starting to apply an exterior composite sheet material. The weather has not cooperated and work has been slowed by 3 weeks of constant rain. I hope to have the dome finished this weekend-weather permitting.

There have been a few questions about the material I am using for my frame. I have updated my web page with some details. I will also start a new thread on the topic.

Bill

http://www.astronomyasylum.com/observatory.html

I finally got a semi dry weekend after another week of straight rain. I fabricated a dome slit door and side skirts. The door will slide up and over the top of the dome. There are only a few small jobs left on the dome, and it should be completed next weekend; then I hope to install wheels on the base structure and mount the dome.

Details can be found at the below link

http://www.astronomyasylum.com/observatory.html

Bill

Hi,

Here is another construction update. I have completed the dome and dome slit cover, and the dome is installed on the base structure. The steel and Bituwell plate construction appears very strong, but is also very light. The entire dome can very easily be rotated with one hand. Its been raining for the last two days, and the inside of the dome is completely dry. The only problem spot is at the bottom of the dome slit cover, but I will install some flashing on this to take rain away from the dome base ring.

I used clear plastic on the dome slit cover to give plenty of natural lighting for working inside the dome; I do a lot of tinkering with my telescope drive system on rainy days and this will give natural lighting while keeping the rain out. I will fabricate a removable inner cover to block light when not in use. I installed wheels on the dome slit cover and it slides up over the top of the dome. The wheels just ride in the plate corrugations. I still need to fabricate a locking mechanism and do a little caulking on the dome slit cover, but its also basically finished.

The next job is installing centering bearings to keep the dome centered as it rotates, then its time to install the floor and siding. I have uploaded several new dome pictures to my website (the link is included below or use the home page link in my signature). I will try to post a picture below.

Bill

 http://www.astronomyasylum.com/observatory.html

Yet another update on construction:

Despite terrible weather comming in from England this last weekend, I completed the dome centering bearings and dome slit rain skirts. At least with the dome installed and weathertight, I can finish up a lot of small details inside the observatory-irregardless of the weather.

I installed a centering bearing system to keep the dome centered on its axis and also keep it pressed firmly against the top bearings. The dome rotation is very smooth and easy. Due to the lightweight materials, the 3.3 m diameter dome can easily be rotated with one hand. I am certain that I eventually will automate the dome rotation, only because this just gives me something else to design and build.

I have uploaded several pictures of the prototype and final centering bearing systems, which can be found on my website.

Bill

Hi, heres another update on construction:

I installed a latch system to hook the opened dome slit cover onto the back of the dome. This consists of two large hooks that latch onto the top of the dome slit when the cover is rolled up. I have posted some pictures of this system on my web site:

http://www.astronomyasylum.com/observatory.html#Slit_Cover_Locking_Hooks

I also started dry fitting the flooring. I had planned on using plywood, but determined that 25 mm thick pine boards would cost 50% less. I will have to do a fair amount of mitering to fit the 10 triangular floor sections, but it is worth it to save 50% of the estmated flooring costs. A link to this section of my webpage:

 http://www.astronomyasylum.com/observatory.html#Floor

All thats left is the flooring, the siding, and running electrical and data lines. I hope to finish these jobs over the next two weekends.

 Bill

Heres another construction update:

The observatory floor is installed and finished. This was the first deck type floor that I have constructed; after several hours of mitering boards I began regretting building a 10 sided structure, a square sure would have been less work. It took most of the weekend to cut, water treat, and finally install the flooring, but I'm very pleased with how it looks. I have uploaded a picture of the finished floor to my website at the below link.

 http://www.astronomyasylum.com/observatory.html#Floor

I had hoped to also install the exterior siding this weekend, but rain stopped all outdoor work. Hopefully next weekends update will read "Observatory Completed", but this is also dependent on the weather forcast, which already looks bad.

Bill

Another Update:

I put the siding on today and construction is just about finished. I used 6 mm plywood that was water treated and bent around the 10 sided structure, giving a pretty good approximation to a circular base. We have near hurricane force winds expected tonight, so I get a chance to see how good of a carpenter I am (I'm crossing my fingers).

I had hoped to finish the observatory this weekend, but another rainy day has slowed construction. There are only a couple of small jobs left: I installed a conduit for electrical and still have to run the wires. I need to put a rain skirt on the bottom of the dome base ring, the door needs a latch and lock, I need to fabricate a locking mechanism for the dome slit cover (right now I use several woodworking clamps to hold it closed), and I need to build a wedge for my telescope-that will bolt into the concrete pier.

I have updated my webpage with a couple of pictures (Exterior Siding Section).

 http://www.astronomyasylum.com/observatory.html#Exterior_Siding

Bill

Another construction update:

The observatory exterior is finally finished! Today I installed rain skirts on the dome base ring and gave the entire base structure a second coat of oil based water treatment. Next weekend I will install the electrical and complete a few unfinished interior details, then the obseravatory is complete.

We had near hurricane strength winds last night, and the entire structure made it through without damage.

 http://www.astronomyasylum.com/observatory.html#Dome_Rain_Skirts

Bill

Hi, heres another update:

I had hoped to be finished today and move my equipment into the observatory next weekend, but more bad weather slowed the progress. The major construction is finished, only small details are left. This weekend I fabricated a locking mechanism for the dome slit cover (I was using large woodworking screw clamps), put an extra rain skirt on top of the observatory door, strenghtened the rain skirts on top of the dome slit cover, did a little caulking, and installed latches and locks on the door.

I hit a snag with the dome rain skirts due to the dome overhang. It had originally planned to have a 10 sided base structure and this would sit significantly under the dome overhang. When I sided the observatory, I found that 6 mm plywood could be bent around the structure to a circular form; this looks much better than a faceted base structure, but decreased my dome overhand. When the rain skirts were installed, they made contact with the exterior siding and caused the dome to drag and rotate harder. So this week I will probably take the rain skirts off and fabricate something new. I will probably have to make a spacer to move the skirts outward and just use lots of silicon to seal the skirt tops against the corrugated dome exterior. I may cut skirts from 6 mm plywood and bend these around the spacers. Hopefully this will only delay the move in day by about a week.

We have had lots of wind and rain last week, and the dome is very tight and dry. The overlapping corrugated Bituwell plates really sealed the dome well. There were only one or two problem spots where the dome slit cover meets the dome, and these were fixed this weekend. The dome survived near gale force winds last weekend, so the structure looks sound.

Bill 

This has come along quite nicely Bill despite the poor weather.

I do have a question.  Having that clear panel is a great idea for natural light to enter so you can tinker inside your dome on cloudy days.  My question is if it is raining and you can't leave your door or slit open how did you plan on ventilating your dome so you can work inside?

Thanks again for the great views of your project.

L

Hi Leo,

Thanks for the comments. I'm planning on installing a solar powered vent fan to give a constant daytime ventilation (at least as constant as anything solar powered can be in this perpetually overcast part of the world!)...or possibly a regular electric vent fan that runs off of a timer.

Another issue is that its always cold here-even the summers if you can call them summers. So overheating isn't too much of a problem. Theres also the option to rotate the dome facing downwind and only partially open the slit cover. Since this slides up and over, it can be opened and still give some rain protection, etc.

 Bill

Hi,

I had time today to look at the rain skirts that were giving dome rotation problems. I removed the old skirts, which were dragging against the structure. I cut 2 cm thick spacers and refit 10 cm wide wood rainskirts. The 2 cm spacers give clearance between the rain skirts and siding, and the dome rotation is once again smooth and easy.

I still need to cover the gap between the rain skirt tops and the dome exterior. I will use small scraps of Bituwell plates that can be wedged into the gaps. I will seal all seams with silicon (probably this weekend since rain is forcast for the remainder of this week). I have updated my webpage with some new pictures.

http://www.astronomyasylum.com/observatory.html#Dome_Rain_Skirts

Bill

Finally, the post I have been looking forward to uploading!

The Observatory is completed! This weekend I ran the electrical and finished the dome rain skirts. There is actually one exterior job to do: putting a ring of stones around the base to absorb the force of rain falling from the rain skirts-but this is a job I can do later. I have updated my website with a picture of the completed rain skirts (below link). It was a messy job and took almost 5 tubes of silicon to seal the entire dome skirt.

This week I will fabricate a base for my telescope to mate with the screws in the concrete pier, then move the equipment into the observatory next weekend. Its been 5 and a half months from breaking ground on the project to completion.....and I can't wait to finally use the observatory.

 http://www.astronomyasylum.com/observatory.html#Dome_Rain_Skirts

Bill