Bat wing/Flip top observatory design

[han59]

My new observatory is now one month ready. It only needs some painting. Below some pictures and a link to the building report. Maybe useful for some:

http://www.hnsky.org/observatory2.htm

The design is called bat wing or flip top. Please advice me if you have a better naming. It is located in the Netherlands.

The roof of the observation can be opened manually using handles. The two halves open at the peak of the roof and are hinged to the sides of the building One halve opens to the south and allows imaging of objects lower then 20 degrees above the horizon.

This clamp shell roof design is not very often used. The big advantage is that less ground space is required. To make it success the two roof halves needs to be very light. The northern half is about 15.5 kg and the southern half is 14 kg. The halves are made of 0.35mm galvanized metal roofing plates with wooden support. The southern  half is made of lighter wood 20.5x48 mm . For opening the half a "step stool" of about 40 cm height is used to be able to handle the 15 kg weight comfortable. In close position they two halves are locked.

The floor space is 2x2 meter (6x6 feet). The walls height is 1.725 meter from the floor and rooftop is at 2.265 meter from the floor. The telescope can freely move under the roof.

The foundation is made using 4 big concrete tiles 0.4 x 0.6 x 0.05 meters which where dug in and will spread the total shed weight of 700 kg sufficient. The space under the floor is enclosed using other additional concrete titles to prevent old leaves and debris to enter.

 A pier of oak wood is installed mechanical isolated from the floor. The oak pier is 0.15x 0.15 x2.6 meters pole and was dug in manually and no concrete was used. The pier is 1.16 meter above shed floor level. An oak pier should survive typically 18 years in the ground and some extra bitumen coating was applied as an extra precaution. The walls are made of Douglas fir tongue and groove joint wood ordered in lengths of 4 meters.

A permanent power cable is installed and extra 80 cm earth rod as an extra precaution. The required 12 volt switching power supplies do not provide 100% potential free power and all 12v minus connections and the computer housing where earthed using this extra earth connection.

The HEQ5pro pier top is based on two thick steel plates, 200 x 150 x 6 mm. The two rectangle plates including the main 60 mm hole for the HEQ5 Pro where ordered at a local machine shop for Euro 43. Further drilling, machining and painting was done at home to save costs. The bottom plate is screwed with four "lag bolts" to the pier. To prevent the wood splitting, the holes for these bolts where pre-drilled and placed not to close to the sides.

A wifi link allows remote control from inside the house using Windows "remote desktop" feature.

To open the roof half after unlocking the first step is to step (lowered) on the step stool and to push the roof open manually. When the roof half reaches the end position the forces increase but in a high position on the step stool this is manageable. The ropes have some flexibility which is a plus.

 

The oak pier just before digging in:

 

Experimental stabilization fins:

Foundation build on four big tiles:

Roof detail:

 

In raining conditions:

Side view:

[andyboy1970]

My first design was the same but after several years of use and a move of house I got fed up with the dew forming on the roof then dripping into the Obsy when the roof is closed.

Now I have a roll off roof.

[frugal]

11 hours ago, andyboy1970 said:

My first design was the same but after several years of use and a move of house I got fed up with the dew forming on the roof then dripping into the Obsy when the roof is closed.

Now I have a roll off roof.

What was it about the bat wing design that caused dew to form?

[andyboy1970]

With the roof open the dew falls on the open roof panels which are actually the inside when you close it.

[han59]

After 5 weeks haven't noticed any condensation yet.  If so, it could drip to the outside. Ventilation in closed position should be good. Maybe I should install styropor plates on the inside in the long run.

Han

[andyboy1970]

Ventilation will help. I also used desiccant bags to keep it dry.

[Adaaam75]

This is the overall design I tried to use when converting my second shed into an obs. I thought it would be cost effective and save on the eyesore of wooden runners which are standard with a rolling roof design, I wanted to potect the asthetics of our garden as best I could. Unfortunately, although the design plans were spot on and I was able to convert the shed, re felt and water proof it, the issue came when opening the roof itself. Needless to say I was somewhat optimistic with the standard 12mm t&g timber roof of  a 2.5m X 3m shed roof!

Don't get me wrong, i am able to lift the two 100kg+ halves of the roof (at the moment!) however the two issues are, once they go past 90 degrees and start to drop with gravity and how strong I will be when i'm 50!

I have considered a pully system but do you know what, i've given in and gone back to the drawing board. I've accepted a rolling roof is really the only way forwards and although I'd like to conserve space like you Neb, I can only concur with Proto and feel it is the better option for me personally. But the reason I chose the flip top design initially was partly down to the desire to be different and find alternative ideas, as you have.

Well done mate.

[andyboy1970]

15 hours ago, Adaaam75 said:

This is the overall design I tried to use when converting my second shed into an obs. I thought it would be cost effective and save on the eyesore of wooden runners which are standard with a rolling roof design, I wanted to potect the asthetics of our garden as best I could. Unfortunately, although the design plans were spot on and I was able to convert the shed, re felt and water proof it, the issue came when opening the roof itself. Needless to say I was somewhat optimistic with the standard 12mm t&g timber roof of  a 2.5m X 3m shed roof!

Don't get me wrong, i am able to lift the two 100kg+ halves of the roof (at the moment!) however the two issues are, once they go past 90 degrees and start to drop with gravity and how strong I will be when i'm 50!

I have considered a pully system but do you know what, i've given in and gone back to the drawing board. I've accepted a rolling roof is really the only way forwards and although I'd like to conserve space like you Neb, I can only concur with Proto and feel it is the better option for me personally. But the reason I chose the flip top design initially was partly down to the desire to be different and find alternative ideas, as you have.

Well done mate.

I was the same, didn't want permanent runners so I have one detachable and the other is permanent but it's next to the fence anyway so didn't matter.

Pictures during construction.

[han59]

The key to success for flip top design is weight control.  Reports from Adaaam75 and others warned me that weight is a major design issue.  The weight of my best half is 14 kg. About 6 kg for the thin 0.35mm metal roofing, 6 kg for the wood and the remainder for screws. So even the wood thickness and screw counts. You have to do the math so the weight calculation beforehand.

I also made a simple test setup from which I learned that 1) the weight forces increase multiple times if the roof half reaches the open position maybe 20 degrees above horizon. 2) You have to stand high enough to handle the half comfortable by hand.  3) Maximum weight to handle comfortable is about 15 kg for me.

When standing on the "step" my shoulders are about 40 cm above the  hinges.

 

Here my simple test setup to get the feeling of the forces:

 

Forgot to mention, As a precaution I also have made a stick of about 4 meters to be able to lock the two halves in open position for windy conditions. The halves open north/south and the main wind direction is from west so this hasn't been a problem up to now.

And here links to two successful flip-top/bat-wing designs:

http://www.downunderobservatory.com/equipment.html
http://www.company7.com/optec/observatory.html
 

Han