New Forest Observatory planning and Sketchup.

[BRAMLEYD]

Hi All,

So I've been planning my ROR observatory in the New Forest for a few months now and have been picking up loads of good tips from here on the way. So now as I am further forward in my thinking I think It is time to give a little back in the form of my sketchup design and to canvass a bit of feedback and advice.

Firstly my design for a 14' x 8'  Observatory can be found be found here:

http://dombramley.com/astro/ObservatoryMk2.0.3.skp

There are quite a lot of layers to play about with and the telescope and pier are (hopefully) to correct scale. The Pergola is to the west where I have a bad horizon obscured by large trees. My best view is towards the East.

The design has picked up a fair bit of detail along the way - primarily as I have had to wait ages to get Planning Permission. Living in a conservation area my permitted development rights were removed when the previous owner built an extension. All a bit of a pain in the rear really. Especially as a tree protection officer has got involved and mandated a no-dig design -  So my  pier base wont be as depp as on the design.

Still all granted now - though I'm probably gonig to wait until the weather starts improving before puring any concrete.

The observatory will house (initially at least)  a William Optics FLT132 on an NEQ6 used primarily if not exclusively for imaging.

Couple of things in particular I'd be interested to hear opinions on are;

1) How high have you piers been? Standard size specified by Pier manufacturers appears to be 42". But I reckon once height of floor and walls is taken into account 52" sounds more likely for a longish refractor.

2) What have people been using for automating roof opening? I'm thinking of maybe a single phase motor with a Rack but not sure what HP or spec etc. The observatory will be close to a neighbours house so I need it it to be as quiet as possible,

Anyways - reckon this is the start of a fun adventure. S  would love to hear your comments and feedback!

Dom

[BRAMLEYD]

I should have included some pictures of the design in my first post so you can see what is in the sketchup without having to download it. So here are a couple of views of the plan in various states of undress:

[r3i]

Best of luck with the build and look forward to seeing how it progresses. Sounds like you have had plenty of fun and games with the planners but hopefully now that's all behind you.

My only comment on your plans is to ask why you are proposing to motorise the roof? This tends to be done if remote operation of the observatory is the intention or if moving it manually would be physically difficult/impossible for the owner. When designing my observatory I had grand plans to automate the hind legs off it but in the end I've kept things as basic as possible (less stuff to go wrong and all that).

[BRAMLEYD]

Thanks Mike,

Totally understand the sentiments. Guess my motivation is twofold:

1) It will be a fun project for cloudy nights and part of my job is promotion of Internet of Things tech so will make a great demo example for that.

2) More practically, I will mostly be imaging through the night whilst I am asleep, so would ideally want it as a rain safety feature. Admittedly my current  solution of automating a light in the bedroom to wake me up would still be a viable alternative to motorizing the roof!

I'm not sure If I would automate it straight away, but want a good idea how I would do it so I can incorporate it into the design.

Cheers

Dom

[rwg]

Your plans are looking good

I used sketchup extensively when planning my build and by planning every component in detail I saved myself a lot of hassle during the build. It helped me catch several things in my initial plans that would have been very difficult to build in practice and redesign around the problem with no wasted materials. My observatory build is detailed here : http://www.astronomyshed.co.uk/forum/viewtopic.php?f=35&t=19209

Your roof worries me just a bit - it's quite flat, so snow loading could be an issue if we get any more cold winters. Also, you will probably want a diagonal brace to keep the framing square until you put the boarding on. I left my diagonal brace in place as it doesn't get in the way of anything.

Depending on your pier height and how low your horizons are, you may want to add one or more fold down flaps to get views closer to the horizon. This is particularly valuable for views to the south.

When it comes to the build, beware that unless your cladding timber is fully dried it will shrink several mm in width as it dries, leaving gaps between the boards. I ended up removing every board and refitting them after about 6 months. To be honest, I'm not sure what else I could have done as I didn't have the space to dry that amount of timber effectively under cover. I deliberately didn't hammer the nails home the last few mm on the first fix because I was concerned about this - on the re-fix I used DeckTite coated screws instead of nails.

cheers,

Robin

[r3i]

Some great advice from Robin.

It would be worthwhile adding a pitch to the roof as a good fall of snow can be rather heavy.

Angled bracing on the framework adds a lot to the rigidity of the structure.

I also got some shrinkage of the cladding during the summer months particularly on the sides in direct sunshine. That's a good tip about fitting them so that they can be subsequently refitted without too much difficulty.

[Garethr]

Not sure I would be too worried about snow loading TBH. At roughly 15lb a cubic foot when was the last time we had that much snow even in the uk let alone new Forrest. Keep the design simple and don't over engineer things that's what I'm keeping to with my build. Even if we did get exceptional snow surely a quick sweep off would sort the issue. We have enough stress with cloudy nights , bad tracking and a hundred other bits to deal with. A few feet of snow would be right at the bottom of my list for design considerations.

[fondofchips]

Some answers to your questions

1. Pier height, probably the most difficult thing to get right in an obsy, it depends on your height & the height of your obsy walls.   Mine are as follows, I'm 6' 2" tall & my obsy walls are 6' 6" tall & the pier is 1260mm tall (including adaptors) to the bottom of my EQ6 mount. I have 2 scopes, the 102mm Lyra refractor works OK at this height, the 200mm Newt needs a 10" or so step to get to the eyepiece.  I'm not too bothered about objects low on the horizon, but just in case I had 2 bolt on pier extensions made to adjust the height 100, 200 or 300mm taller.  I've not had to use them with my current scopes.
2. Motorised roof, not a fan of automatic functions they are only OK if they are fail safe (switch off when a problem is detected), for example I was doing some adjustments to my mount during the day with the obsy roof closed, I left it for a while & when I came back the mount had continued tracking & came close to doing some serious damage to my scope.
3. Flat roof, my obsy was constructed by a professional shed builder who told me that a steep angle would be more likely to leak to the inside of the obsy, apparently the faster rain runs off a shed roof the more likely it is to end up inside. This way you do not need to fit seals etc on your ROR roof runners. Just overlap the roof down below the level of the runners.  I've had no problems with water inside my obsy & it is in the most exposed part of my garden.  Also the viewing part of the obsy needs ventilation anyway, don't insulate this part of the obsy as the wood will naturally breathe & damp will escape through the wood.
4. Free heat - if you can have some small windows in your warm room that catch the sun during the day.  This free heat is pulled through in my obsy by a small fan (30mm) that pulls this warm dry air through into the observing room 24/7 keeping the astronomy gear in the observing room dry.  Your warm room won't be as cold after a sunny day either & will require less heat.
5. Take your time, think every stage through, it took me nearly 18 months to complete my project & I've not had the hassle or expense of correcting mistakes.  The only thing I got wrong was the alignment of the pier adaptor to North & had to strip it down again & drill and tap a new locating pin hole.
6. Enjoy - the first light with a new obsy is very special indeed.

Pictures here: -  http://stargazerslounge.com/gallery/album/2477-my-obsy-build/

Cheers,

Fondofchips.

[BRAMLEYD]

Firstly - many thanks for all the advice - this really is invaluable. I'm no builder and haven't ever constructed anything of note before. Infact I have only had a garden for a couple of years now having mostly lived in flats. 

I agree with Robin that Sketchup is amazingly helpful and quite staggering that such a powerful piece of software can be downloaded for free. Takes a little while to get to grips with it but well worth the effort. I've spent quite a while exploring different frame structures and different wheel designs.

Seems to be different schools of thoughts on the roof, but I think I will look to reinforce it with some angled support. I don't like the idea of it distorting if it needs to track nicely along rails.

The cladding shrinkage is not something I had considered (though as I said I know nothing about woodwork!) - does this apply to tanalised wood also?

I haven't included drop down sides as I'm not blessed with low horizons, and I will mostly be imaging so should try and avoid low elevations. 

Another question; have you all found any issues with water ingress from the end of the roof? The sides can overlap the runners and provide protection but this isn't possible at the end..

Cheers

Dom 

[Gina]

Brush type draught excluder is what I used with good effect

I agree - SketchUp is fantastic - I used it to design my obsy too

[Mikyg]

I should have included some pictures of the design in my first post so you can see what is in the sketchup without having to download it. So here are a couple of views of the plan in various states of undress:

hey i too am in the planning stage of a new obey and was wondering what software you used for your sketch up? looks good by the way

[BRAMLEYD]

Thanks Miky,

The software I used is Google Sketchup:  http://www.sketchup.com/  It is pretty awesome once you get the hang of it. Free too,.

Feel free to download my plan to get you started:

http://dombramley.co...toryMk2.0.3.skp

(though bear in mind I haven;t built it yet so it might be rubbish )

Good luck with the plans!

Dom

[Mikyg]

ha ha i'm sure it won't be rubbish. i'm building an obey for my dad and his warm room is going to be in his conservatory so some major planning needed lol but just got the green light to order the materials so its all hands on deck.

[perfrej]

I recommend a garage door opener motor. You want everything to be 12V so that you can close up and be safe in the event of weather. They often drive standard bicycle chains so it is easy to get everything fixed.

Slant the roof a bit. The Russian Arctic and Antarctic Institute (AARI) last year issued a long range forecast for the supposed heating of the planet, which speaks of Arctic temperatures falling and ice buildup on the increase from next year to 2035. Couple their forecast with the fact that the planet hasn't actually seen a temperature increase in the past 18 years and you may have snow in the New Forest as well

Pier height is something that always amazes me. If you are not actually going to stand out there and peek at the wonders of the universe with your own eye you can halve the building and pier heights. In our remote observatory we have four piers, all 40cm high including adjustment. The only important thing is that the camera clears the floor

/per

[BRAMLEYD]

Thanks Per,

Do you drive the roof with a rack or do you use a pulley system?

I've decided to to increase the gradient on the roof. One thing to be aware of: unlike Sweden, if it snows in the UK we can't go anywhere! so I'll always be around to scrape it off if necessary!

Your point on pier height is logical, but I think the reason people go with full height structures is twofold:

a) Garden layout often dictates the observatory needs to be near a border and thus the the telescope needs to be high enough to look over the fence. In my case I am on the SOuth border.

Aesthetics. Most people choose a ROR design as they don't want anything to look un-natural in their garden. In my case this is not just a personal preference, as the National Park Authority won't give planning permission to anything that isn't in keeping with the local surroundings.

Personally I think you have the right idea: build it in someone elses garden!

Dom

[perfrej]

Haha! Yes, we use a bicycle chain and a garage door opener. Very simple.

/per

[michaelmorris]

On the quetsion of pier height, as I see it you have a number of potentailly competing factors -.

To maximise possible targets, you want the the scope mounted as high as possible.

To minimise the risk of the scope getting buffeted by the wind, you want the scope mounted as low as possible.

To minimise glare from local point-source light pollut, you want the scope mounted as low as possible.

To maximise the flexiblility to add extra bits or change your set up, you want the scope mounted either a low pier or have the facility to change the pier height in the future.

Want ends up bg the best solution will depend on your individual circumtsances and budget.

[NickK]

On the quetsion of pier height, as I see it you have a number of potentailly competing factors -.

To maximise possible targets, you want the the scope mounted as high as possible.

To minimise the risk of the scope getting buffeted by the wind, you want the scope mounted as low as possible.

To minimise glare from local point-source light pollut, you want the scope mounted as low as possible.

To maximise the flexiblility to add extra bits or change your set up, you want the scope mounted either a low pier or have the facility to change the pier height in the future.

Want ends up bg the best solution will depend on your individual circumtsances and budget.

To maximise targets the scope needs clear view of the lowest point on the horizon - however that is if you don't mind shooting through miles of water vapour and sky glow! In the UK that realistically means planning against the sky profile (i.e. the arch where it doesn't start diminishing the image).

Ground effect - is also something to consider - you probably want to get the scope out of the lower boundary - making the image more stable.. but that then depends on the heat coming off the ground around it too (obsy, houses etc)..

Olly's spot is up high.. so that helps - even with 40 cm Per peirs! it was -15 degC hard wind chill when I was there (I remember the six layers, four head layers etc..). Hence that's a little extreme!

[Gina]

All good points   I made the height of the warm room just sufficient to allow me to stand up in it.  Then the scope room a bit highter so that the roof rolled off over the warm room.  A lower side on the south side with top part that rolls off with the roof and a fold down flap on the east wall provide views down to the horizon to the south and east.  Views to the west and north were limited be trees and buildings.  It works pretty well

When I decided I wanted a second pier, mount and imaging rig, I went for an equipment only observatory with everything remote controlled.  The southern boundary to the property is only a low pig netting fence backed up with an electric fence and about 3ft high so no need for a high pier.  The other side is a field owned by my neighbour who has beef cattle so no obstructions.  This will be a mini observatory and is described in another thread.  Minimal size just big enough to take my triple imaging widefield rig on NEQ6 mount.

[BRAMLEYD]

Thanks for the advice guys - all very helpful.

I have modeled my FLT132 scope and NEQ6 mount in the sketchup also - so I have been able to check the viewing angles with different wall heights. Factoring in a bit of headroom in the vain hope that one day I may win the lottery and buy a 14"  ODK -  I think a 52" pier is the way to go.