Domes - Whats out there that is good and won't break the bank?

[Tomatobro]

I made up a device using a finder scope (with cross hairs), a compass and a digital angle finder. I plotted in 10 degree intervals the horizon.

Its surprising how a few metres change in location can open up the visible sky.

[sloz1664]

6 hours ago, RayD said:

Looks great.  That looks like a Velleman board?  I use a couple of these with the Lesvedome driver on my roof and can't fault them.

Yes Ray, I use two Velleman K8055 boards, one for dome rotation & the second using the switch interface for individually powering my equipment in conjunction with a Velleman 8 channel relay module.

Steve

[Jkulin]

6 hours ago, Tomatobro said:

I made up a device using a finder scope (with cross hairs), a compass and a digital angle finder. I plotted in 10 degree intervals the horizon.

Its surprising how a few metres change in location can open up the visible sky.

That's really quite an interesting thought, I usually go to CdC or DSO Browser and determine the angle of my targets to see whether they will clear or no.

[Tomatobro]

I used Blocklayer.com to print out the scale. A most useful website.

[Astrokev]

Neat set up

[Jkulin]

I haven't gone away just been doing loads of thinking.

I am not an engineer, far from it but various things are going through my mind and one of the options was to try and build my own Octagonal summerhouse style observatory, as the ones I have seen which I would need to convert don't look too brilliant and I would need to probably pay a carpenter to come and modify, so I thought if I could sit down and design such an obsy then it might be easier to build rather than buy and convert.

Now although I'm fairly good with a computer I have never used a CAD program, is there anything easy out there to get to grips with designing it on my computer and then visualise it?

This is just one of the options that I'm looking at, I have loads of questions such as how I could butt together the 45 degree angles of each panel, how could I seal the edges of each panel, how I could build the roof octagonally  and make it slide and also keep it sealed.

Building an Octagonal sliding RoR obsy would probably function much better than trying to rotate and motorise a roof.

I've also thought about building an attractive summer house base and then buy an dome roof, but then there is more expense with rotating it.

There's a couple of Obsy companies planning to be at the Practical Astro show next month, so may potentially have further discussions with them.

First thing though is to start drawing ideas and then render to see how they would look.

Appreciate any help, Thanks.

[Astrokev]

I'd suggest giving SketchUp a try. I used this to design my observatory and it's quite popular with a number of other SGL builders. 

It's a 3D drawing program (poor- man's CAD!) and the basic version is free, downloadable from the web. Simple Google will find it. It'll do everything you need, including dimensioning, which I found useful to print dimensioned drawings of the different elevations when I came to build the obsy.

It's fairly easy to use once you get to grips with it. There are loads of videos on the site to get you started. 

Good luck

[Gina]

Yup - what I used to design my observatory.

[Jkulin]

Thanks Kev and Gina, I started watching a video at 02:30 this morning in bed, but then gave up as I was tired.

I'm hoping I'll be able to draw up a octagonal design on it, so I probably need to watch me videos ?

[Gina]

Why do you want an octagonal design?  Isn't this just making things much more difficult?  An octagonal design makes more sense for a dome rather than a ROR.

[Jkulin]

46 minutes ago, Gina said:

Why do you want an octagonal design?  Isn't this just making things much more difficult?  An octagonal design makes more sense for a dome rather than a ROR.

Hi Gina,

The only way to appease my wife (I say that tongue in cheek as she really is a darling) is to make the Obsy blend in as best as possible in the middle of the garden, by making it look like a Summer House worked for her and she relented, and I have to admit I want to work with her, not against her.

If I keep it to a RoR design, then it would appear not to be that difficult to build incorporate it into our existing Pergola by running two rails out to it.

Keeping it to an Octagon would mean that I have two parallel sides, whereas a Hexagon would not be as easy or seamless.

A RoR would appear to get rid of the issues with needing a motorised dome so reduced costs and a hopefully easier design.

I hope that explains it a little better, I'm no engineer Gina, far from it, so trying to keep things simple.

[Gina]

Nice explanation - thank you ?

[Rusted]

I haven't read the whole thread but would warn against building an octagon.
As I did. Two floors high to clear the trees and hedges!
If you draw a circle over an octagon you will find you need a much larger dome [or hat] to avoid rain running inside the building.

I now much prefer round buildings and would definitely build a round one next time.
Cylinders can look very smart with vertical planking or corrugated, metal roofing sheets, running up and down.
No useless corners and no flat walls pushing you inwards.

Easily built from glued and overlapped arcs of plywood forming circles using a cheap, handheld jigsaw.
Or a router on the end of [plank] radius bar for a little more precision.
You join the cut circles with vertical [roofing batten posts] simply notched into the outside radius of the curves to build a strong skeleton.
Or roll your own on the ground. Using the metal, corrugated roofing fixed over the circles. [Rather more difficult!]

The dome would be cheaper than the full height GRP walled observatory.
A roof could be flat or sloping to drain easily. Or arched for domestic bliss!
With half-round {semicircular] gables. Dead easy!

[Gasman]

Haven't read all this thread so not sure if you have dismissed Pulsar's yet but I love mine and I acquired it second hand (right place right time ?) about 12yrs ago and other than coat of paint once a year had no probs at all.

 

Steve

[Rusted]

99%, of those who expressed an opinion, agreed that sage green is a good colour for an observatory.

But that octagons make absolutely no sense.

[saac]

On 17/02/2019 at 18:55, Jkulin said:

Right bit of an update and potentially something unusual, my wife is really working with me on this and she has fed in some ideas.

Our home is only about 20 years old and the gardens were never planned to be like beautiful Victorian rambling jobs with mysteries around each corner.

I've created a roughly scale drawing of the layout with the grey part our patio and the small grey block the pier: -

 

The wooden trellis is a pergola style and you pass under it to enter the garden, the front of the patio has an 18" high brick wall which meets either side of the pergola.

Now one of the potential ideas we have come up with which wouldn't look unattractive is to erect an octagonal summer house in the middle of the garden with a sliding roof and then extend two rails out to the pergola that the roof could slide on to clear the walls of the summer house, it would probably have to be eight sided so that you had enough roof to slide on: -

Something sliding like this: -

 

I'd have to either extend the width of the pergola or build a new one to match the width of the roof of the summer house.

The summer house walls would be false, just made to look like windows.

What do you think, would it work and how simple do you think it would be to make the roof slide off?

Jkulin, using an octagonal summer house is perfectly feasible and makes for a really good solution when you want something that is aesthetically pleasing. I did exactly that with my own observatory; my original thread is below.  Watch out the links to the photographs have expired so I've attached a new link that should get you to some photographs of the build.  I opted for an all cedar construction summer house to give it a bit of protection against rot etc.  As far as roll-off roofs are concerned this is a fairly straightforward  conversion. Having said that because it is a standard summer house the roof is fairly heavy so I opted to put in some additional cross bracing to the roof together with a third roof rail which runs centrally and is removed once the roof rolls back.  So far I have had no problems with condensation and remain completely happy with the observatory. I have since installed some plywood lining to the back wall together with a desk and electrical  power and data cables; I generally now run it remotely.  If you want any other information or photographs then I would be happy to help. 

link to one drive photographs:   Octagonal Summerhouse Obsy

Jim

 

 

 

 

 

[tooth_dr]

5 hours ago, Rusted said:

99%, of those who expressed an opinion, agreed that sage green is a good colour for an observatory.

But that octagons make absolutely no sense.

Fab! Any interior pictures? I’m planning a brick octagonal observatory in the future.  

[Rusted]

54 minutes ago, tooth_dr said:

Fab! Any interior pictures? I’m planning a brick octagonal observatory in the future.  

Check my profile and choose "About me" for a number of images. Or:

https://stargazerslounge.com/profile/54930-rusted/?tab=field_core_pfield_12

My advice remains: Octagons are a very poor choice of building where all space is valuable.
The dimensions across the flats [walls] are so much smaller than a round thing.
Which means you lose a foot, or easily double that, of useful diameter across the width.
Few of us have the luxury to be able to waste that much space!

BTW: Brick or block, unless painted white, will absorb lots of sunshine.
And then let it out slowly all evening and night.
Just when you want stable temperatures around your telescope.

Even sage green painted, 4mm plywood has a very low thermal mass.
So it becomes modestly warm [90F] in hot sunshine but loses the temperature gain in mere seconds.

I have been monitoring my dome's air and panel temperature continuously during my hours of  solar viewing.
A passing cloud is enough to knock the dome panel temperatures [inside] back to near ambient.
The thermal differential between the air temperature inside the dome [in shade] and outside temperatures [in deep shade]
has not exceeded 10F so far. The difference soon drops to only 4-5F once a cloud crosses the sun.

Only rarely do I see thermal agitation on the limb of the sun, or Moon.
So my dome and two story building seem not to suffer from so called "dome seeing."
I have used 220x in bright sunshine on the sun in WL [including today] with hardly any thermal issues.
The same on the Moon after a full day of sunshine. My building is thermally "innocent."
Probably thanks to all wood and plywood construction and being raised well above ground thermals.

 

 

[Jkulin]

21 hours ago, Gasman said:

Haven't read all this thread so not sure if you have dismissed Pulsar's yet but I love mine and I acquired it second hand (right place right time ?) about 12yrs ago and other than coat of paint once a year had no probs at all.

 

Steve

Hi Steve, I had a good look at the Pulsar at the PAS yesterday and as it would stick smack in the middle of the garden it wasn't for me

Sorry @Rusted  I can just see my wife being happy about something that size in the middle of the Garden, it has to blend in, not look like a sore thumb, I have to admit that you have made a beautiful job of that though, you need to read at the beginning of the thread as to what my criteria was.

@saac Jim, that looks exactly what I am looking for, I'll spend some more time have a look at you thread and link and if you don't mind may need to contact you, thanks for taking your time to send me that. Just a quick question, how did you manage to close the gaps at the side where the runners are so that no water could get in?

[Gina]

I wondered that.  Sealing an octagonal observatory with a roll off roof must be quite tricky.  It's bad enough with nice simple rectangles.

[saac]

2 hours ago, Jkulin said:

 

@saac Jim, that looks exactly what I am looking for, I'll spend some more time have a look at you thread and link and if you don't mind may need to contact you, thanks for taking your time to send me that. Just a quick question, how did you manage to close the gaps at the side where the runners are so that no water could get in?

Jkulin the roof overhangs the walls enough so that water shedding from the roof falls straight down and not backward into the observatory; the roof is effectively acting like a giant umbrella. I had initially in mind to close the gaps using the brush type seal you often see being used on garage doors. As it turned out I didn't need to and the air gap means there is plenty of unrestricted air flowing. I'm certain that this is the reason why there is no condensation in the observatory. I think the gap and irregular roof shape also helps to keep the roof from lifting off in high wind - with a gap all-round any pressure is quickly dissipated so reducing wind loading.  Having said that the roof is also clamped down.  So far it has survived some pretty awful weather.  The only time I have had water leaking into the inside was from the rail tracking. The track has pre-drilled holes and the ones that I had not used were letting water seep through. Once these were sealed with frame sealant then all was dry again.  

Before I had added a bit of lead flashing above the door so that water would not drip straight down from the roof.  The lead flashing sits under the rail with the excess going inside the observatory and is then turned up. I guess this idea could also be extended to the other sides but I've not yet felt a need to do so. 

 

[saac]

1 hour ago, Gina said:

I wondered that.  Sealing an octagonal observatory with a roll off roof must be quite tricky.  It's bad enough with nice simple rectangles.

It's been surprisingly straightforward Gina as in the diagram above. My back garden is relatively sheltered so the rain from the roof just sheds straight down. I've never really had the wind blowing the rain back into the inside - touch wood  

Jim  

[Jkulin]

Thanks Jim, this Obsy would be in the middle of the garden, so would need to do some careful planning, have you got a link to the rails and rollers you used, I also noticed that you could have chosen concealed rollers, I imagine that would keep the rook lower?

Height like yourself might be a problem, so I may have to either build the obsy myself or plan to left it higher to clear when I use a larger OTA.

[saac]

John, I used a company called FH Brundle: excellent service , can't fault them.  They provide an option of either v groved or round  galvanised track in 3 m sections.  I elected to use the round track; in retrospect the v grove track may provide a higher degree of resistance to side movement. Having said that, I have not had any problem with the round profile which I think provides a lower rolling resistance. Brundle's have a variety of wheels available, I went with the caged wheels which were mounted in their own bracket - made installation that bit easier.  I haven't fully recessed the wheels into the roof timber, something I have been meaning to go back to do; as you say this would lower the profile a little. As for the height of the roof line you can always adjust that to suit by inserting shims; adjusting the height to your local situation should not be a big problem.  One of the things you will need to do is add some bracing to both the roof and the walls. This is not as onerous as it may sound nor particularly difficult but it adds further weight to the roof in particular.  You will want to be sure that the roof can be safely supported. I'll post some more pictures showing the roof section from inside but it will be later on in the week. One thing I would recommend is to inspect the observatory fully built before you purchase it; some roof profiles are easier than others to convert. You effectively want a roof that is separate from the rest of the construction.

Jim 

https://www.fhbrundle.co.uk/products/05GD289__3_Metre_Bolt_Down_Track_for_20mm_Rd_Grvd_Wheels

https://www.fhbrundle.co.uk/products/0515094__120_x_30mm_T_Wheel_With_Internal_Support_Round_Groove_Max_600kg

[Rusted]

11 hours ago, Jkulin said:

Sorry @Rusted  I can just see my wife being happy about something that size in the middle of the Garden, it has to blend in, not look like a sore thumb, I have to admit that you have made a beautiful job of that though, you need to read at the beginning of the thread as to what my criteria was.

 

A "sore thumb" is strictly in the eye of the beholder.
My wife gave me the thumbs up for my colossus but insisted it wasn't a tall, square box.
I usually do as I'm told but would now build a tall cylinder.

Gasman's sage green Pulsar is drop dead gorgeous IMHO and fits its situation like a glove.
It sets a remarkable standard for the acceptable face of "observatoryness."
A standard white one in that situation would be a completely different matter.
The "grass green" Pulsar option is a bit too "loud" for my tastes.
I think they'd sell many more in sage green.

Given your criteria I'd suggest a Patrick Moore style, octagonal "greenhouse."
You can grow tomatoes up the pier and look straight through the glass.
It will soon become completely invisible to the naked eye.