ROR Design Questions

glend (Glen) · #1 06-01-2015, 08:36 AM

With my pier in place I am trying to finalise the dimensions of my ROR Obs. The goal is to make it as small as possible to accomodate slew room for my 10" f5 imaging newt, or my 125mm iStar f12 refractor when mounted on the NEQ6. With lengths of 1300mm and 1500mm respectively (when parked perpendicularly to the walls) I am considering 1800 x 1800 as the minimum required floor area. Does that sound ok? I am curious about the benefits of a warm room section or general space for my imaging workstation, and would think that extending one dimension to 2400mm should be more than enough room for the workstation, battery equipment, kettle, etc..

Secondly, re the ROR section, assuming it rolls back just enough to expose the scope section of the room and leave a roof over the workstation section, is there any need for it to go further? And what materials can be used for the roofing to keep it as light as possible (am considering Suntuff Poly roofing panels), anyone using them?

The goal is to build it as six simple panels (Deck, four walls (one with the door), and the roof - all of which can be disassembled to be flat packed to another site in a trailer if required in the future (like to my son's property) So it will sit on treated pine posts - no slab. Re wall height, I would like to have standing headroom inside with the roof closed but a section of the wall could be attached to the roof and thus part of the wall and roof would roll off together to get a lower horizon level - however does this not mean rolling off to the side so that the front of the roof gable goes with it - or going with a skillion roof to simplify.

Any advice on insulation, sarking etc is welcomed..or anything else you can think of..

Thanks Glen

ZeroID (Brent) · #2 08-01-2015, 01:01 PM

1800 x 1800 will be too small. Mine is 1800 x 2700. You need the space to one end to just get in and move around. I have to be a little careful when I am working low south as the cameras only just miss the back wall. I have a 900 wide desk and seat\cabinet at the west end and it is not a warm room although I can hide under the roof slid back. No way you could add an internal wall to create a proper warm room.
I'd prefer to be about 2.4 x 3.0 meters but you make do with what you can afford and accommodate.
Insulate your roof maybe to reduce daytime heat but leave the walls. You want it to cool down as fast as possible as evening comes on.

glend (Glen) · #3 08-01-2015, 01:35 PM

I am just in the process of digging the footings for an 1800 x 2400 obs. I pegged it out and sat inside and worked out that size would just be ok. I can put my portable imaging workstation in one back corner.

glend (Glen) · #4 12-01-2015, 08:51 PM

In doing some design drawing for the roof it occurred to me that a opening turret would be an option - with a flat top turret like a battle tank and a sliding hatch. Has anyone in Australia attempted one? I found a couple of examples online but I guess they are harder to execute than a simple RORO design.

ZeroID (Brent) · #5 13-01-2015, 09:25 AM

I've looked at building a simple panelled 'dome' for mine to gain some roof height for the 10" Newt. Biggest problem is it raises the horizon line for everything else. Also complicates construction and involves a rotating joint at the junction and weather seal issues.
My 'Split Roof' is working well for me at present. Easy to open, locks down and seals quickly and is adjustable for the width needed to be open and thus useful for dew mitigation. No rollers required as it is light and each half is quite small so they just slide along the top rail of the shed. I just wish I'd made it a bit higher in the middle although it's ok when all the refractors are loaded. If I leave the Newt on the mount I cannot park it at home position but that is manageable all the same.

glend (Glen) · #6 21-01-2015, 08:19 AM

What is the view (pun) on wall height for a RORO observatory? I have done some research that leads me to the view that is it dependent on your surrounding clearances and what you intend to do - for example, low angle targets look involve looking (or imaging) through at least twice as much atmo as high targets. As I am mainly interested in imaging with my 10" newt, concentrate on higher altitude targets (or wait for them to get there) and thus I am considering that wall height for me maybe more a function of desired headroom (for the scope) with the roof closed.

I am thinking of a wall height of 1.5 metres, with a gable roof to provide the scope clearance and headroom with the roof closed. Is there a common formula for determining this design factor? What are the heights people use?

BTW this observatory is being built under the NSW Exempt Development rules (no Council apprval requird), so max height is limited to 2.5 metres.

ta

Merlin66 (Ken) · #7 21-01-2015, 10:45 AM

Glen,
I've built a few observatories....
the wall height will depend on all the factors mentioned so far...if your surrounding area allows it then a 1.5m wall with sliding/rolling roof section to take it high enough to clear your largest scope (say 0.5m) gives a usable 2.0m overall height.
If you're closed in by other building etc. then obviously the benefits of a lower wall are lost.....then the compromise may be 1.8mm wall and work well above the horizon.

Many years ago I built and octodome on a 3 x 3m breeze block base.
The wall height was 1.5 and the dome just less than 1m. One of the eight panels had a double hinged door (1.2m wide) handy when looking at the horizon. The roof shutter was the same width and rolled on heavy duty sliding door tracks to clear the zenith. This was controlled by a pully system. Easy!
I used this of a few years with a 12" f5 for SN search. No real issues, no drama, it just did it's job.

ZeroID (Brent) · #8 22-01-2015, 11:25 AM

Quote:

Originally Posted by glend

BTW this observatory is being built under the NSW Exempt Development rules (no Council apprval requird), so max height is limited to 2.5 metres.

ta

Heck ! I could add another 500 mm easy and still be within spec.
My split roof solution came about because of restrictions on roll off space in one direction. It splits out in both directions, East and West, max about 1.2 meter. This is due to neighbouring boundary proximity. Worked better than I expected as each half is quite light and now the slides have bedded in very easy, one handed almost, to move. Also means you can tailor the opening slot to your target and reduce dew effects. No rollers also means no seals or gaps to worry about, it sits flush on the top plates.

My walls are 1.8 meters, the pier puts the scope up high enough to get 35* all round or better in the E\W directions but LP, trees to east and a small volcano to the NW ( Mt Albert) means I don't have horizon views regardless so I work as high up as I can near the zenith or to the S - SW.

Go and stand in the position you think your pier will be and look around to see what visual restrictions etc you have to contend with. Then plan to get the best options in your design. My East is useless so I could have a 20 meter wall there and it wouldn't be a problem.
You can always extend your pier later as I have if you find it gains some more sky acreage. When I moved to a 102mm refractor I added 150mm box from where the 10" Newt used to be mounted from.

glend (Glen) · #9 24-01-2015, 09:49 PM

Trying to find some exterior panels for the walls, what are (or have) people used in the past? Hardiplank seems to get pretty heavy quickly as you stick it on the side. Exterior ply would work as long as its properly sealed with epoxy sealer. I am not a fan of weatherboards as they are too much work and seem more costly than ply. What are the options?

ZeroID (Brent) · #10 27-01-2015, 06:43 AM

I looked at exterior grade ply originally, good couple of coats of paint would be ok over here. Settled on a cheap commercial tin shed in the end. Light coloured and I beefed it up to support roof rails etc. It's in a fenced sheltered backyard location with no insulation but that might not work in Aust temperatures.

glend (Glen) · #11 09-02-2015, 12:04 PM

Trying to decide whether the door will swing in or out. I am leaning towards having it swing out to get more useable room inside. What's the consensus? I know there are potential weather issues.

ZeroID (Brent) · #12 09-02-2015, 12:38 PM

Out, unless my Ob was doubled in width I could not work with an in swing door. You need to be able to open it fully to shift gear in and out.

sharpiel · #13 09-02-2015, 11:01 PM

If space is a premium then definitely out.

glend (Glen) · #14 26-02-2015, 10:33 AM

I have noticed that a couple of recently completed observatories (and beautiful work they are), use interior wall lining material. My view on this has been that lining the interior walls is, while great to look at, a potential problem long term, why: they can hide things that are happening behind the panelling, increase cost marginally, encourage pests, impede cool down, etc. I have not lined my walls - yet, and this has proved useful already in allowing me to see a small leak where rain was running back the track and into the wall joint. Just wanted to get the views of long term observatory owners on this topic.

Merlin66 (Ken) · #15 26-02-2015, 11:00 AM

I never bother with lining previously....
With the latest "PlanA+1/2" design the walls will be lined out with 6mm ply ( to match the rest of the shed)
I'd say, fix the leaks......then put on some insulation and lining boards.

5ash (Philip) · #16 01-03-2015, 01:45 PM

Quote
" 1800 x 1800 will be too small. Mine is 1800 x 2700. You need the space to one end to just get in and move around. I have to be a little careful when I am working low south as the cameras only just miss the back wall. "

I agree , my observatory started out as a wind break enclosure comprising 6 pine posts arranged in a hexagon , clad with an above ground swimming pool roll of steel sheet. The dimensions to opposite hexagonal walls is 2.1 metres. Now the enclosure is the base of an observatory with a rotating hexagonal roof and an adjoining tiny computer room. I have tried a 10" SW Newtonian and it was a squeeze , a 10" SN was much better and a 9.25" SCT was just right. I hit the " goldylocks zone " for a suitable telescope. I am at present running a SW 120 ED and now find the camera something to negotiate in the dark. However with plenty of luminous dots and use of luminous paint it becomes easier. Anyway the bigger the better. Determine the goldylocks zone for your telescope if you want the minimum size of observatory or the observatory will do it for you.
Philip