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pjogrinc

Planning an observatory, which style?

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I'm planning on building an observatory, but living in Northern Minnesota country side presents some unique problems. I'll list them here, with my ideas and hope you can provide additional input. :hmm:

1. Frost line requires minimum of 6 foot deep pier, with water table in the spring at 4 ft down and mid July is 5 ft down and in September it is 7 ft down.

Hydralic affect would be interesting, if any. No visable pitching of ground over the last 3 years anywhere around observatory site.

2. Ground fog up to 3 feet high typical 2 nights a week, disappating usually 2 to 3 hours after sunset with excellent clear skys.

3. Due to being in a high hymidity area, I believe a dome would be better. Also have to consider snow loading, code here is 25 LB minimum.

4. Planed size is 8 ft by 14 with a warming/computer room on the north side.

I've entertained the thought of a 2 pier system versus a large T mount plate on top of a single pier for running 2 telescopes, but wonder how often I would use 2 different telescopes vs. 2 telescopes piggybacked.

Any additional comments/info would be appreciated.

TNKS, Pat

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I think with snow to contend with that you should be aiming for a dome shaped roof. Snow becomes very heavy and could damage a flat roll off roof design. The dome could be placed onto a concrete platform about 1 metre high to raise it off the ground. this could help with your ground fog problem maybe.

Tom

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G"day Pat

I've gone the Roll off roof with a pitched roof.

Admittedly its not as grand as you are planning but it serves me well

My warm room is in the house 50 ft away (south) as well as a garage 50ft away (west) both hard wired with 2 runs of cat5e

http://www.grampianstars.com.au/observatory.htm

My neighbor down the road built a 2,4mt dome and it is like a sauna inside

2 piers is a nice option

I'm planning on building an observatory,....... :hmm:

.............

3. Due to being in a high hymidity area, I believe a dome would be better. Also have to consider snow loading, code here is 25 LB minimum.

4. Planed size is 8 ft by 14 with a warming/computer room on the north side.

I've entertained the thought of a 2 pier system...........

TNKS, Pat

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Howdy, Pat

Just a few thought's...

1. Frost line requires minimum of 6 foot deep pier, with water table in the spring at 4 ft down and mid July is 5 ft down and in September it is 7 ft down.

If your pier is encompassed by a concrete pad, which has a footer at a depth of your building code, 36" should be adequate.

As far as the roof, I like the idea of a two pier ob too. You might check into those heat cables that install on the roof that you can plug in, to melt off the snow...The roll off roof 'could' be on a slight pitch say a 3/12 pitch and allow for snow melting. Gonnna be just a tad complicated, but do-able.

And here's an old link you might find helpful...

http://www.myastrospace.com/forums/showthread.php?t=1126

Also working on some idea's for a wooden pier.(if it can be done with metal...chances are it was done with wood first.)

have a good'un:smile:

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Talked with one of the local sign installers, large upright display signs, and he suggested just going down 3 ft and making the pier base 3x3x3 ft high and level with the ground or add some more height, but no more than 3/4 the distance from ground level to bottom of floor joists. This is assuming that I remove any and all top dirt to get down to the gravel bar (from glaciers) this area is located on. Test holes on the property indicate that this should be no deeper than 2 feet in most areas, but I had to go down 5 feet for the left front corner of the new garage and less than 1 foot for the right rear. Had to hall in 90 cubic yards of class 5 for the bed (26 x 38 ft. approx.) that the garage sits on to bring it up 6 inches above grade.

Anyway, back to the concrete pier. He said that it would float a little, but since I would have adjustments at both top and bottom of the pier, that the movements over time could be easily taken out and should not be much, but going down 6 ft would reduce this floating. He said he could drill a 3 ft or 4 ft diameter hole, 6 ft deep in 10 to 15 minutes! Lets see, by hand would be... by back hoe would be...

I thought about a roll off roof, but am concerned with the dew issue with normal humidity running around 65 %. Roll off roof would be constructed with a 4/12 pitch rafters on 1 ft centers with 2 inch sheet foam insulation with steel roofing on top. Side walls attached to this would be 2 ft in elevation with a 6 inch skirt to eliminate water and insect intrusion. This roof would roll off north and stop over the warming area. The actual viewing area would be 8 x 9 1/2 ft. with 4 ft high walls. Snow can be easily removed with a snow rake to help keep the loading down. Roof would have to be bolted down when not in use do to the occasional 50 mph storms we have come through occasionally.

A dome roof would be a little harder to construct do to support issues and turning issues, but snow loading would be considerably less of an issue. An 8 ft wide by 5 ft high would work perfectly if sitting on a 4 ft wall.

The more I talk about it and redo the plans for the umpteenth time, I think I will go with a single pier with a common mounting plate predrilled for both telescope mounts. The floor will be on footers 18 inches off of the ground to help eliminate the ground fog issues. Electrical will have to be by extension cord due to permitting issue with a 'shed' versus an 'inhabitable building' issue. This issue is still in discussion with the county inspector as he has never ran accross an observatory before. Construction will begin in the spring of 09.

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Hi Pat,

I also agree that the Roll Off Roof design would be better for your purposes. I think snow loading could be a problem.

Sounds like you live in quite a damp area, so raising the obs up off the floor would also be helpful. I'd go higher than lower. 1 metre upwards would make a huge difference.

What Tim said about using somekind of heating system to melt snow would be quite helpful but I'm not sure how hard this would be to implement.

Ray

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Hi Pat

I built a timber roll-off-roof observatory, and used this for some six years.

However, living in rural location, and backing onto open farm land, the observatory is quite exposed to the wind, especially in winter, when there are no leaves on the trees.

This meant that long exposure CCD imaging, was difficult under windy conditions, as the slightest tremor of the scope, resulting from a gust of wind, would wreck the image.

Therefore, this spring. I removed the roll-off-roof, and built and installed a rotating turret arrangement.

This now provides excellent protection from the wind.

You can see the observatory on my website at:

http://uk.geocities.com/daves.astronomy@btinternet.com/

Dave

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G'day Dave

Hey a "Darlek" roaming free in the UK now that's a surprise :biggrin:

I'm thinking of a r.o.r. dome for the same wind issue

I had 30 knot winds yesterday :eek:

Hi Pat

I built a timber roll-off-roof observatory, and used this for some six years.

However, living in rural location, and backing onto open farm land, the observatory is quite exposed to the wind, especially in winter........

Therefore, this spring. I removed the roll-off-roof, and built and installed a rotating turret arrangement.......

Dave

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I'm thinking of a r.o.r. dome for the same wind issue

A r.o.r dome? Interesting. I've never seen one of these before. Do you mean the dome actually rolls away from the scope Rob?

Ray

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That would be nice to compare your plans to mine and look for improvements I can make in mine.

As I have access to large of sheets of card board, I was planing on making a 1/2 scale mockup in the barn to check for flaws. My roof opening original plan was to be 4 ft. wide so I would not have to rotate the dome while imaging. I have since realized that, 15 deg. rotation.hr, 4 ft wide opening is way to large (DA!!!). A 3 ft opening would be sufficent, as I decided not to go with a CCD camera and will be using a DSLR. The DSLR will be modified this winter to increase red sensitivity.

The snow loading will still be an issue, so the dome will have to reinforced to carry the load. The opening on mine was to be a dual flip open versus a sliding. This was to eliminate water intrusion due to wind, but the more I think about it, a rolling opening would be easier as long as I used spring loaded rollers so I can lock it down when not in use. Also considered a 45 degree flat roof (12/6 pitch) for the dome. That would work and be easier. Here is a link to one that I helped build while I lived in Boise, Idaho.

http://www.visitidaho.org/mapsimages/view-photo.aspx?id=3769

County inspector has just got back to me with the following info:

1. Building has to be less than 100 square feet or will require and permit.

2. Building can not have permanent power without a building permit AND electrical permit and inspections.

The county inspector is interested in seeing how this turns out and asked my permission to take pictures after it was done for his collection. He also asked if he could bring over his family to take a look through the telescope.

I guess, your attitude when approaching the county zoning/permitting people really makes a difference. I went in and asked for their help, explained what I was trying to do and showed them a couple of pictures of other peoples observatories. Their first answer was, a what ?? They researched their database and found only one observatory in the county records. That one is at the University of Minnesota, Duluth, UMD.

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Gday there pjogrinc.

Send us a PM with your email and ill send them to you.

You can compare all you like , might even come up with some new ideas.

I built mine 2 years ago , still standing strong works like a charm.

And on that note , im going there now:biggrin:

Cheers

Patrick

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I am in the materials sourcing stage of my shed project.

I'm pretty sure I'll go for a roll off gable roof style with timber trusses and wall frames on a concrete slab (if the form working and concreting works out cheaper than an off-ground deck on stubby concrete or metal piers (Ive a slightly sloping ground in my back yard).

We get winter cyclones and the sometimes even tropical cyclones and tornadoes here from time to time so I need to ensure everything is well attached to the ground or the slab or can be securely bolted down.

Will have metal sheeting (corrigated) on the walls and insulated metal roof. I wont be insulating the walls or lining them at this stage - though I may install my old window mounted 1/2 HP refrigerative A/C in a convenient location even though I'll need to run an extension cord from the house to the shed to run (will be handy for cooling the shed before a session and for cooling the DSLR on warm nights) , everything else will run from 12V batteries and jumpstarter packs or internal batteries (lappy and DSLR).

Gets hot in summer here and the insulated roof sheets will keep the heat sinking down.

My two main gems (the New Atlux for the main scope and the old CG5 for the skypatrol rig) will be permanently mounted on concrete piers (I'll retire the tripods for "away missions" or holidays and trips when I take some gear with me, concidered future proofing and using steel tube piers bolted to the slab but I think this will work out too expensive as I have to pay someone to fabricate these (do the welding).

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G'day there Patrick

Say I'm investigating a dome structure for the roll off roof modification

Some big winds on occasion here

was the ply / masonite difficult to work with ?

nice looking obs obs by the way :smile:

G'day there Pat,

I have PDF plans for a 8ft dome made out of plywood and skinned with masonite that i used for making my observatory if you need them.

http://www.myastrospace.com/forums/attachment.php?attachmentid=239&d=1170061372

Cheers

Patrick

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I took Patricks plan's and combined them with what I had. His plans are great and showed me a couple of points that I had missed and would not have releaized until in the construction phase.

Due to a high water table in my area, had to change the design on the concrete peir and had to plan in the year-to-year movement of the pier. This required extra clearance around the pier to oservatory floor, changing the pier tube to concrete pier base mounting bolts from standard course thread to fine thread custom made one and elevating the floor for the observatory around the pier/dome joint. This was to allow for a sloped roof to shovel off the snow.

Currently, it's -28 deg C out we have 2 1/2 feet of packed snow on the ground. My contractor friend says the frost line is at about 5 1/2 feet down. Right at my water table level where the observatory is going.

This is goig to be an interesting project this summer.

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I took Patricks plan's and combined them with what I had. His plans are great and showed me a couple of points that I had missed and would not have releaized until in the construction phase.

Due to a high water table in my area, had to change the design on the concrete peir and had to plan in the year-to-year movement of the pier. This required extra clearance around the pier to oservatory floor, changing the pier tube to concrete pier base mounting bolts from standard course thread to fine thread custom made one and elevating the floor for the observatory around the pier/dome joint. This was to allow for a sloped roof to shovel off the snow.

Currently, it's -28 deg C out we have 2 1/2 feet of packed snow on the ground. My contractor friend says the frost line is at about 5 1/2 feet down. Right at my water table level where the observatory is going.

This is goig to be an interesting project this summer.

it's -28 deg C out , Brrrrr..... too cold for me . Watch out those brass monkeys who've lost their ....

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Currently' date=' it's -28 deg C out we have 2 1/2 feet of packed snow on the ground[/quote']

Man that's cold! Some serious design work needed for that climate.

Ray

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G'day there Patrick

Say I'm investigating a dome structure for the roll off roof modification

Some big winds on occasion here

was the ply / masonite difficult to work with ?

nice looking obs obs by the way :smile:

Gday Rob.

If your handy with tools this is an easy way to do it.

Not hard at all , just take your time, masonite is easy , just make a cardboard template for each section , then make a little bigger and plane it to fit.

Good luck and post some pics when you have some to share.

I took Patricks plan's and combined them with what I had. His plans are great and showed me a couple of points that I had missed and would not have releaized until in the construction phase.

Due to a high water table in my area, had to change the design on the concrete peir and had to plan in the year-to-year movement of the pier. This required extra clearance around the pier to oservatory floor, changing the pier tube to concrete pier base mounting bolts from standard course thread to fine thread custom made one and elevating the floor for the observatory around the pier/dome joint. This was to allow for a sloped roof to shovel off the snow.

Currently, it's -28 deg C out we have 2 1/2 feet of packed snow on the ground. My contractor friend says the frost line is at about 5 1/2 feet down. Right at my water table level where the observatory is going.

This is going to be an interesting project this summer.

Im so glad i could help you in some way,keep us all updated , and post up some pics of the area for the obs, dont see snow here,,,,,,ever...lol

Cheers

Patrick

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Hi Ian,

I like the roll off gable design as well. When time, money and the boss permits, I think I am going to go with somethng very similiar to this.

http://www.durangoskies.com/bdp_8x10.html

I really like the use of garage door track and rollers for the rolling off feature.

A few size changes, as I would like to have two piers...and most definitely a WARM room, lol.

Cheers, Tim:smile:

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Hi Ian,

I like the roll off gable design as well. When time, money and the boss permits, I think I am going to go with somethng very similiar to this.

http://www.durangoskies.com/bdp_8x10.html

I really like the use of garage door track and rollers for the rolling off feature.

A few size changes, as I would like to have two piers...and most definitely a WARM room, lol.

Cheers, Tim:smile:

I'm also looking at two piers in mine and I want the shed to roomy enough for any future telescope size upgrades that I might have later some time in the future.

One of the options for me is an off the ground deck arrangement , comes down to which is cheaper , a concrete slab (3mx4m) or the off ground deck arrangement a lot of guys go for.

Termites are a problem here , I'm a bit worried about them getting into the timber if the deck is close to the ground , chap next door just had room added the termites promptly ate out his skurting boards and window frames .... my house is OK but I am paranoid about them so regularly go under the house (I can walk about under most of it and don't need to stoop much where floor is closest to the ground , and I check each brick pedestal and the from brick work for the tell tails.

I'm getting close to being ready to visit Bunnings or Mac's Hardware to order the roof trusses , and either prefab wall frames or enough treated pine to make my own wall frames .

A call to Boral and they told me they are out of stock of 8" diam Formatube for a week or two (need if I go for concrete piers, and or a deck).

Got a mate at Onesteel who might be able to get me a couple of 8m lengths or channel , and some square tubes.

I wonder if the Boy Scouts still do odd jobs .... might enlist them to help me with getting the steel onto the roof or lifting the prefab roof onto the channel shaped rails . not good on ladders (I'm too fat to climb them safely).

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Temperature bottomed out at -42 C this winter. December was -4 C colder/day on average than normal and January is looking to be running at -3 C colder on average/day than normal. Hard to believe in global warming.

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WoW what a difference in OZ

we had +46.2 C (in the shade) out here yesterday

its been only 2 years since the last extreme heat

the maggies were standing in the shade of the red gums panting

Temperature bottomed out at -42 C this winter. December was -4 C colder/day on average than normal and January is looking to be running at -3 C colder on average/day than normal. Hard to believe in global warming.

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I know chaps who have closed up their "observatories and brought their scopes and cameras inside (for storage in a nice dry and cool) cupboard inside their airconditioned homes because their observatories are too hot (in South Australia and Victoria and Western Australia , I expect guys in the Northern Territory and Queensland do this too , expectally if there are TCs handing about).

Pretty worm out there and if my detacted double garage is any indication , installing my old sash window mounted refrigerative aircond in one of the wall in my shed will be a good idea. I'd dambed hot in there even though I've left the front roller door open all night and all day.

Am I becoming a old fuddy duddy and a woose .... I've stayed inside with the Fujitsu split aircon running set at 23deg C and it's been running pretty much continuously since this time week , had some real stinkers here in Newcastle , looks like summer has finally arrived !!!!

Anyone here got a small refrigerative airconditioner in their observatories ? do you find it's helpful ?

(Probably handy on those really warm sticky nights (about high 20s and into the 30s --- we do get them !!!) for cooling the DSLR when imaging a little and helping reduce noise .... just an idea .... as well as helping the old stargazer keep his cool !!!

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WoW what a difference in OZ

we had +46.2 C (in the shade) out here yesterday

its been only 2 years since the last extreme heat

the maggies were standing in the shade of the red gums panting

Toasty .... bet you are staying close to the airconditioner , or in the water if you've a pool.

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