The DaltonSkyGazer Observatory Looking towards the South.
The DaltonSkyGazer Observatory is designed around the 8ft Explora Dome by PolyDome. I purchased the observatory dome and original building in December of 2009 used from a friend in Long Lake, Ny. This happens to be the same month and year when DaltonSkyGazer.com first went online. In the original design the dome building was shorter and the control room area was smaller than my existing design and setup. I redesigned the dome building such that the walls were 2 feet taller than the original design. This allowed the control room to have a higher roof due to it’s placement just below the bottom lip of the dome. The final outcome was much more headroom offered in the dome and heated control room area. This means less chance of banging one’s head at the entrance when leaving(common issue in the standard Explora Dome building design) and less chance of hitting one’s head on the counterweight bar of the gem type mount. The total height of the observatory dome from ground to highest point is a few inches over 12 feet in my new design. When standing in the dome it now feels very spacious inside due to the extra height added to the wall. There is room for 8 people to stand comfortably in the dome portion, while the heated control room seats two to three people.
Some of the changes to the observatory were based off of information provided by the previous owner based on his personal experience with the original design.
The Original Observatory as I bought used can be seen in the two pictures below. I decided to redesign and build the control room with new materials. The height of the dome structure was also increased by 2 feet, this required me to replace all of the vertical studs on the existing dome wall. See two images below:
This image shows the Original Control Room when the observatory was at previous owner’s property. I totally redesigned this to be taller and larger. I did not save any of the control room material, I built the control room 100% with new material
This image shows the original pier and dome interior area. I chose to build my own pier from scratch. I also decided to redesign and replace the original dome walls with a design which was 2 feet taller. This allowed for a much larger feel to the dome area and less chance of smashing one’s head into something.
The pier design I chose to build is constructed in two parts. I poured my own 12″ concrete pier footer to a depth of five feet, one foot below the frost-line for my location and by code. The concrete pier extends approximately two feet above ground. The base of the pier is flared like a pyramid which resists any upwards pull during the winter when the ground freezes. The pyramid shape to the footing gives the pier extra surface area to work against the forces which would act upwards on the pier when the ground is frozen. The concrete pier was reinforced with rebar horizontally and vertically, which I bought in precut lengths at the local Home Depot for several dollars per piece. I inserted three 12″ long 3/4″ diameter J-Bolts into the concrete pier which allow for attachment of my homemade steel pier to the concrete footing.
The concrete pier was finished up just as night set in, timing to dig the hole, mix, and pour was a total of 3hrs. The soil is primarily sand the 5 foot hole took all of 25 minutes to dig with help from a friend.
The concrete pour should be planned well in advance. It is very important that one fabricate a wooden template so the J-Bolts are lined up properly when inserting them into the concrete. I added small gauge wire to the lower portion of the J-Bolts before they were inserted into the concrete, this was prepared a few days before the concrete pour. I also kept the concrete covered and moistened for 3 days after the pour, this slows down curing process which gives the concrete greater strength. It is very important when working with concrete to clean out the mixing container between batches whether one uses ground tray or a mixer. If you leave the old concrete in the tray or mixer than the concrete will cure at a much faster rate. You want to ensure that everything is in order and well organized on the day you plan to pour. You do not want be running around last minute, you have limited time to work with the concrete. You should mix the concrete with a little bit of water at a time, the concrete should be fairly firm and moist, but not to the point it sags or runs.
I recommend that you check the cardinal points and mark the area very well before the day comes to pour the concrete pier. I used a compass and Sun method to ensure alignment of the pier would be accurate. I also marked the cardinal points using my LX-200GPS after it had been polar aligned as a reference point using paint and string-line. The critical alignment and cardinal points were scribed into the steel pier to ensure accurate placement of the steel pier on top of the concrete pier. I used one of the J-Bolts which was aligned with True North as a guide.
I fabricated the steel pier using 6 inch schedule 80 pipe which I had laying around in the garage. There is no need to use heavy wall pipe, one can use schedule 40 pipe for pier construction. The thickness of the wall does not affect stability of the pier or reduce pier deflection by any means. The most important variable when building a steel pier is the diameter of the pipe one uses. Every step up in size lowers deflection seen when a horizontal load is applied, and dampen time is greatly reduced with each pipe size larger in design. I am quite content with the performance of my 6 inch diameter pier, deflection has been a non issue since installation of the pier. If I hit the pier it quickly settles down in less than 1.5 seconds. My pier adequately supports the 12 inch Meade Lx-200- GPS mounted on the Meade Ultra Wedge with an 80mm APO riding piggyback and added imaging gear. I went a full 10 months at one point with the same mount on the pier. During the 10 month time period Polar Alignment never changed, this assures me that my design was built in such a manner that it supports my gear without any issues.
Dan’s Pier Top Plate for the CGEM/ATLAS Mounts
I designed the steel pier with a two plate design. If one were building a pier for a very large capacity mount I would recommend going with a single plate design. The double plate design I chose was more than adequate for my current needs. The lower plate in my double plate design is welded permanently to the 6 inch pipe. The top plate has four – 3/4″ threaded rods attached to the bottom plate via nuts which are welded to the top plate. The threaded rod extends downwards to the lower plate where it is affixed by means of a double nut system. This allows for the height of the pier to be adjusted by several inches. The double plate system is very solid, there is absolutely no play or deflection noticed in this setup. My setup is designed primarily as an imaging system, very rarely do I visually observe from within the dome.
I drilled the top plate to accept two different top pier plate adapters which were purchased and fabricated by Dan’s Pier Top Plates. I can highly recommend Dan’s Pier Top Plates for anyone who is looking to purchase a pier adapter plate for their mount. Dan also offers concrete pier kits which include the top plate and a bottom plate which attaches to the top of a concrete telescope pier. If you are thinking of purchasing a kit from Dan I recommend that you order it 6 weeks in advance of your pier build.
A solid concrete pier is an excellent choice for stability and cost if a steel pier is out of one’s price range. A permanent pier is one of the best investments for astrophotography, even if one does not have an observatory. A solid telescope pier greatly reduces setup time for astrophotography and allows for permanent polar alignment. One could easily build a small enclosure over a pier such that their telescope is pier mounted year round for a very low price. I welded a 5/16 inch steel plate to the bottom of the pipe to act as a footing and added gussets to stiffen the pier up. I would recommend going with 1/2″ steel plate for the footing and for the top plate. The plates I used were 5/16″, they work well, but it is better to overbuild, I chose to save a few bucks. The pier is approximately 49″ in height from the base of steel footing to surface of the top plate. This height can be adjusted by about 4 inches either side of 49″. If I ever have the need to change the pier it is very easy to fabricate a new top plate or new double plate if required. Being that the pier was built from steel, it would be very easy to remove a section of pipe or to install a new section if the height had to be changed in the future. The pier is leveled under the foot plate by means of shims.
1 inch Steel Banding was fastened to the wall studs which stiffens and strengthens the Dome Building. The steel banding was pretensioned all the way around during installation.
The round dome building was designed with 23 uprights for the walls and a diameter of 10 feet. The wall slopes in another 2 feet to allow for the 8ft Explora Dome to ride on the plywood ring and wheels. The point where each stud slants in acts as a lever and can be leveled via shims to fine tune the ring height. I do plan on upgrading the ring in the future with the newly offered aluminum ring and wheel-set. The easiest way to fabricate a wooden ring is with a router which is attached with a long fulcrum point to dead center of the material which you are using to fabricate the ring.
Steel banding was fastened to the dome studs to strengthen and stiffen the wall. The steel banding was pretensioned as it was installed and fastened to the studs. This adds a great deal of strength to the wall. I actually was able to walk on the wooden ring after installation of the steel banding and it supported me effortlessly. The entrance to the observatory from the control room is located in the back right of the picture to the left.
Testing fit of the CGEM on the newly installed homemade steel telescope pier.
The heated control room extension was built over the course of two days. We installed the the floor and installed two wall frames on the first day. It took a bit of work and patience to affix the control room roof to the dome building. The roof had to be installed in such a way that the roof-line runs barely over a 1/4″ below the bottom of the dome, it could not interfere with the dome. We took our time ensuring the studs and clearances were perfect. I chose to use the same material as the siding on the dome for the roof. The fact that the steel siding is white greatly reduces any heat gain from the sun. The steel roof also allows snow to readily be removed during the winter months. I used 3/4 pressure treated plywood for the flooring on each building. A ground moisture barrier and stone was added under all buildings to minimize any moisture from entering the buildings via the ground. Both buildings were set onto cement blocks to allow for proper air flow under the buildings. In addition, I anchored the buildings to the ground using steel anchors which screw into the ground, chain was then connected to the framing. I anchored the building as insurance against a freak accident happening due to the strange weather patterns we see in my area. We do see tornadoes and hurricanes in Massachusetts. Furthermore, the local Berkshire mountains are known to host some very strange storms throughout the seasons.
I spent quite a bit of time planning out insulation and venting requirements in the dome and heated control room. My primary concern was minimizing any chances for heat gain from the heated control room to the dome. I wanted the telescope and dome area to stay as close as possible to atmospheric temperatures 24/7, greatly reducing cool down time requirements for the telescope. I was also worried about creating heat currents at the shutter opening which would greatly diminish the quality of my images. I attacked this problem with a two prong approach.
The DaltonSkyGazer Observatory Doming. This task was easily accomplished with three people in less than 5 minutes. The dome weighs 180lbs. This accomplishment brought many smiles from all those helping with the build.
The toughest part of the whole build was installing and cutting the Luan base for the slant roof and Aluminum flashing to fit along the outside diameter of the slanted roof transition. Each piece of aluminum flashing was overlapped by at least 8″, a flexible silicone was added to the overlapping joint, and self tapping steel sheet screws with rubber weather-tight gasket and dab of silicone were added to the periphery of the slant roof. It took me several days to cut the flashing and to get things to where I was happy with it.
My first decision was to use spray foam insulation on all walls and the ceiling of the heated control room. Spray foam insulation excels at reducing heat gain by means of conduction. There are three methods of heat transfer which we need to think about. The methods of heat transfer are conduction, radiation, and convection. Spray foam does an excellent job at minimizing heat gain. I also added fiberglass insulation with a vapor barrier facing in the proper direction. The combination of these insulation types worked out very well for me. I easily maintain the control room which is approximately 8′ by 7-1/2′ at a comfortable 68F when outdoor temperatures are at zero degrees F using a 1500 watt ceramic heater set at it’s lowest setting. The ceramic heater is equipped with a thermostat, most of the time it is not calling for heat once the observatory control room is warmed up.
Secondly, I installed a venting system onto the roof of the heated control room. This is very similar to the power vents you see on RV’s. My idea was that by venting the control room I would allow for a means of creating a natural or forced draft out of the control room to a safe place of discharge away from the shutter. This in effect would cause a lower pressure zone in the control room then that of the dome area and therefor create a natural draft which allows the dome air to enter the control room reducing the risk of heat gain into the dome area from the heated control room.
A few more images of the pier and build are shown below:
The CGEM test fit onto Dan’s Top Pier Plate Adapter and my home built telescope pier. The setup is rock solid. Longest stretch of maintaining PA was 10 months before taking mount down, it kept perfect PA for 10 months straight. I can’t be happier with the pier build and installation.
Completion of the 10′ diameter observatory dome building with 8′ Explora Dome in August of 2010. Groundbreaking and Pier pour began on 1 July 2010.
This picture shows the control room just after paint went on. The door was built and installed on the same day.
I had some extra time to think about the control room before the build took place about a month after construction of the dome building. The control room was added in August of 2010. It took 3 days to build and paint the control room. I ended up building my own door for the control room which included a layer of 1.5 inch foam-board sandwiched between the boards it was fabricated from. The door is a fairly strong design to slow any intruders down, my neighbors do keep a look out in my neighborhood. I also installed several security camera’s inside the buildings which upload images to a server on the internet if they detect any movement within the observatory. The security software used can be configured to email, text, or to call my cell phone to alert me whenever the system is activated. You can see in the image to the right that the newly built control room leaves plenty of room for a computer station and shelving.
Installing the Pine Tongue and Groove into the Control Room. You can see the spray foam application on the Northern facing wall in this image.
I ran my communication and power wires then called my friend up who applied the spray foam using a large cylinder of left over insulation from a job he was working on earlier the same day. With the control room attached the distance from the left side of the control room to the far side of the dome was a total of 18ft. This really made the observatory feel quite spacious. I was very happy with the design at this point and was looking forward to having a few nights under the skies to test out my layout a bit before finishing the interior work. For the time being I settled on a temporary desk and computer station install until I was confident of the final interior layout. Work on the interior was pushed back until the Spring of 2011.
Tongue and groove pine is going up, control room is taking shape quickly.
I had a chance to use the observatory from August 2010 into April of 2011 before starting up the interior work on the control room and dome area. I was very happy with performance from the pier installation. The fact that my mount and scope was permanently setup made astrophotography a million times more pleasurable. No more worrying about staying warm or setting up and breaking down equipment. I now go out a few hours in advance of an imaging night and open up the dome to allow for proper cool down of the scope. From the time I fire up the computer to the time I take my first focus test using a Bahtinov mask is no more than five minutes now. I can not emphasize enough how much easier things are. I had gained enough time in the observatory to fully recognize the layout which would work best for me.
In April of 2011, finish work on the interior of the addition quickly resumed. I do regret one thing, adding a dark stain to the pine. It came out looking awful, I should have kept the wood natural and finished it off with a few coats of poly. In the end I painted over the stain and kept the interior a very light shade of tan allowing the room to appear bright when lights are on. You can see the pine tongue and groove installed in the picture above, I am very disappointed that I tried to cover pine with a dark stain, at minimum I should have used a pre-conditioner for the pine tongue and groove. I live with this one mistake now, at some future point I am sure I will put in new boards. I am just happy at this point to have a very nice control room to work from.
Meade 12 Inch LX-200 GPS on Pier.
Wrapping up finish work on DaltonSkyGazer Observatory Control Room. I built an L shaped desk with shelving. More than adequate room for my purposes. Outdoor carpet and a large throw rug were put to to further insulate the floor and to add protection in case I drop any delicate items.
I added several built in shelves on the dome side of the control room. This shelving is used to house my small library of astronomy books and charts. The desk was custom built and is L shaped. The desk starts on the North facing wall in picture to the right, then extends around to the East where the built in shelving is located. I added a wall panel from the floor up to the ceiling at the right hand side of the shelving which is located just to the left of the interior door where one enters the dome. This allowed for a small alcove or corridor to be added where you walk into the dome area.
The final touches were added in July of 2011. It is amazing to see the observatory now after finish work has been completed. I hung up a few framed pictures and charts, adding just the right amount of extra’s to make the area comfortable to work from. Surprisingly, in summer the interior remains very cool, adding the extra insulation and white steel roof made a huge difference to the interior temperatures. I would not hesitate to use the prepainted white siding from Home Depot in a future build. The panels are low cost, durable, and do an excellent job at keeping dome near outdoor temperatures year round.
Recently, I have added an extra monitor in the dome area with wireless keyboard and mouse. This allows me to easily do a PA while located at the scope location. This gives me an extra work area and screen for visitors. Depending upon which portion of the sky I am imaging I have the option of controlling the camera and scope from my office computer in the house. I usually move the dome a few inches every 15-20 minutes for objects located between Southeast and South, if the object is to the Northeast I can get away with moving the dome every few hours.
The CGEM and Celestron 800HD OTA with Meade 80mm 5000 series APO on Pier
The finished observatory can be seen in the image below as seen facing towards the Northwest. The observatory was intentionally built near the tree line, this blocks LP from a nearby city to my West. I can image to the North,South, and Eastern skies.
The DaltonSkyGazer Explora-Dome Observatory and Warm room looking towards Northwest Finish Work on Dome interior was completed in July of 2011. The dome has work benches, seating, and outdoor carpeting. The observatory is hardwired with high speed internet and includes a WiFi setup with WiFi Range Booster allowing for complete coverage of the property.