Skillion roof or gable for roll off roof observatory

[h0ughy (David)]

I am looking at two different colourbond sheds at the moment a skillion roof and a gable roof. what are the advantages and disadvantages of both?

[Bassnut (Fred)]

If you want to close the roof with any scope orientation, then with a skillion roof (I had to google that, means flat ;-) will need high sides and possibly restrict viewing near the horison. A gabled roof allows lower sides, but still quite high ends. I found a gabled roof needs some tricky internal bracing high up to avoid the scope on closing, to stop sag.

It all depends on the OBs size (the bigger it is, the futher away the sides are), how low you want to image, and wether you can park the scope flat before closeing.

[jase (Jason)]

Listen to Fred. He's been there and done that. He'll even tell you how to automate it through his patent advanced roof movement technology.

[RB (Andrew)]

Go on Hough, do a Clark Gable.....you know you want to...........

[Bassnut (Fred)]

jase??

You takin the piss, punk

Motorised closing is easy, wind up a rope with a geared motor, the solution to megadata .

[jase (Jason)]

Originally Posted by Bassnut

jase??

You takin the piss, punk

Motorised closing is easy, wind up a rope with a geared motor, the solution to megadata .

Nope, but I've seen your GRAS obs in action and was impressed how your got the synchronisation of the two shutters working. You sent me a link to a movie a while back. Was a little noisy (could have been echo due to operating it in a confined space for build/testing), but when you're operating it 1,200km away - who cares about noise right!

You still got the designs? Maybe worth sharing...

[Bassnut (Fred)]

umm, nope, thats embarissing, worked a treat untill it got windy, the one condition I couldnt test. The shutters were very efficient sails.

[sheeny (Al)]

Originally Posted by RB

Go on Hough, do a Clark Gable.....you know you want to...........

I bet you a skillion dollars he doesn't...

(groan anytime...)

Need a bit more info, Dave.

If your shed has a gable like 1ponders' then there's no difference when it comes to the height of the walls, etc. Paul's shed looks ideal to me. A gable is easier to build strong over a bigger span.

If you were building your own from scratch, then a skillion is far easier to DIY, and you could get quite reasonable spans and lightweight by using stuff like Paroc. But since you're looking at buying a shed and modifying, look for the one that has a complete roof frame as well as complete wall frames like 1ponders'. It will make life much easier.

Al.

[RB (Andrew)]

Originally Posted by Bassnut

umm, nope, thats embarissing, worked a treat untill it got windy, the one condition I couldnt test. The shutters were very efficient sails.

"Gone with the Wind", hah Fred?

Now you can groan Al !

[Bassnut (Fred)]

Yeah, pretty much . Still used with manual open close tho.

[acropolite (Phil)]

I like gables, they just look better.

Weatherproofing is usually better on a gable roof because of the increased pitch.

Then there's the option of rolling part of the wall as well to lower the height.

Then again a man with your skills could conjure up a nice dome....

[h0ughy (David)]

Originally Posted by Bassnut

If you want to close the roof with any scope orientation, then with a skillion roof (I had to google that, means flat ;-) will need high sides and possibly restrict viewing near the horison. A gabled roof allows lower sides, but still quite high ends. I found a gabled roof needs some tricky internal bracing high up to avoid the scope on closing, to stop sag.

It all depends on the OBs size (the bigger it is, the futher away the sides are), how low you want to image, and wether you can park the scope flat before closeing.

Fred I have 2 pier tech type 2 piers (one for the eq6 and one for the G11) that I can raise and lower at a whim, so the parked position will be fully loaded ready to go. I can either keep the scopes low to avoid the breeze or the neighbours lights or raise them to get a horizon to the east and part of the north. i can see the SCP but have no real southern or western horizon. I thought the high side of the skillion roof can go towards the back fence and the low side to the eastern horizon? the size i was looking at was 3.8 by 2.3 from col western sheds, and getting a custom made welded door made for it?

[h0ughy (David)]

Originally Posted by acropolite

I like gables, they just look better.

Weatherproofing is usually better on a gable roof because of the increased pitch.

Then there's the option of rolling part of the wall as well to lower the height.

Then again a man with your skills could conjure up a nice dome....

too dear for a dome - be cheaper to pay ponders to buy a shed in qld and transport and erect in wallsend NSW

[Bassnut (Fred)]

Thats a fair size, and with the adjustable piers (assuming you dont want to automate closing) a skillion roof would be much easier to build, Anyway, imaging close to the horison is often less than worth the trouble and time, and as you say, wind protection is a bonus.

[acropolite (Phil)]

too dear for a dome

I was thinking more of a roll your own geodesic like Shawn built....

[h0ughy (David)]

Originally Posted by sheeny

I bet you a skillion dollars he doesn't...

(groan anytime...)

Need a bit more info, Dave.

If your shed has a gable like 1ponders' then there's no difference when it comes to the height of the walls, etc. Paul's shed looks ideal to me. A gable is easier to build strong over a bigger span.

If you were building your own from scratch, then a skillion is far easier to DIY, and you could get quite reasonable spans and lightweight by using stuff like Paroc. But since you're looking at buying a shed and modifying, look for the one that has a complete roof frame as well as complete wall frames like 1ponders'. It will make life much easier.

Al.

the shed panels are prefabbed - and delivered to site - all i have to do is pour the pier bases and the slab (one pour, three sections all seperated by high density foam) erect the frame and then get a 2 c channel beams 8m long with two bracing beams in the middle and two steel poles. Much around and get some contraption made up for the roller assembly to fit on the outside into the c channel and some extra flashing to cover up the gaps and keep the weather out. sounds simple no plans yet, but want to buy one as steel is going up in a weeks time apparently making the sheds about 200 dearer the link to the shed prices is here http://www.colwesternsheds.com.au/fi...heds_sheds.pdf

[h0ughy (David)]

Originally Posted by acropolite

I was thinking more of a roll your own geodesic like Shawn built....

i am definitely not that smart or have that ability?

[Ian Robinson]

I've been thinking about something similar - I am inclined to think the best roll off or slide off is a raised tie
http://www.diydoctor.org.uk/project_...russes%201.jpg
is very flat which is good, and looks very rigid .

[kinetic (Steve)]

Sorry, I don't mean to step on anyones toes....but all the talk about
roll off roof observatories ....one question....

Isn't a main factor for building one eliminating wind on the scope?
Or at least minimising it? Do Roll off roof obs suffer windage?

I really don't know....that's why I ask...
I know the shed with the roll off roof is a cheap entry point but
are people aware there is another cheap way in?

I made a foam dome in 2000.
http://mywebsite.bigpond.com/astrosteve/dome.html
Triangles of foam glued together in a geodesic pattern.
I copied a bloke's idea on the net...his name is Joe Garlitz.
http://www.orednet.org/~jgarlitz/observ.htm
Dozens of others have copied it...one being Baz from here on IIS.

It is CHEAP...and it's great fun...and it's portable enough to demolish and
/or take with you if you move.

Best thing I ever did in this hobby was make a dome.
Just thought I'd mention...there is an alternative

regards,
Steve B.

[Ian Robinson]

How big will your slab be h0ughy ? and will you lay it yourself ? with reinforcing within ?