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Need help planning my future observatory with two large scopes

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#1 Tyson M

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Posted 21 May 2021 - 04:17 PM

Hello all

 

I have two large telescopes and want to get this observatory finally going. My 25" f5 dob and my 9" f7.7 istar achro refractor on my losmandy tripod. 

 

No pier, as I cannot have a permanent set up on the ground In order to avoid additional taxes.

 

Unfortunately this means I'll need the whole thing on a deck (Including the support beams to hold the roof while it's off).

 

I bought the skyshed plans which are great, and I'm thinking about going with the 10'x14' observatory. 

 

Does anyone have any tips for my approach? The plans show windows on the front wall, is that really necessary? 

 

Any insight or advice is welcome about this non permanent structure observatory.

 

Regards 


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#2 TOMDEY

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Posted 21 May 2021 - 06:08 PM

Will those instruments fit in a 10'x14' space? As you know, a deck can be quite the trampoline. That's annoying with a small scope and worse with a large one. Might want to consider a "temporary" support to ground below the instrument pad above. Something like this jack-stand in the picture. It wouldn't be there to support the load, but only to dampen/snuff most of the trampoline effect. Just snug it up enough to achieve that.    Tom

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#3 Tyson M

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Posted 22 May 2021 - 07:17 AM

I have decided to scrap the deck. Huge cost and unnecessary. The support beams can sit on concrete blocks and the structure will not be fixed to the ground but not considered movable once built due to rails and support beams.



#4 macdonjh

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Posted 22 May 2021 - 08:12 AM

Tyson M, I understand why you're planning what you're planning.  Something to be aware of: your concrete blocks will shift and settle and your wood platform/deck will warp and sag.  There are a couple of observatories owned by local club members here sitting on decks.  That's exactly what happened to them.  Since you're considering a roll-off roof, it may cause operational problems as the roof support beams/ track get out of alignment. 

 

I hope you can figure something out which checks all your boxes.  Having an observatory is great.  Extra work in some respects, but great for observing.



#5 Tyson M

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Posted 22 May 2021 - 08:46 AM

The more I'm thinking about this the more difficult this is becoming.

 

I am trying to plan out my dimensions but due to the very different scope designs means different placements inside the observatory.

 

The dob base needs to be in the center, with a 10ft arc facing 3 directions of East, South and West. Then the refractor which needs more or less the same but needs A 5ft arc.

 

If you had my two scopes and a ton of space to put an observatory, what would you build?

 

Do I scrap the idea of having the dob set up in the observatory? And just store the dob in there but roll it outside of the observatory and set up each time?



#6 Tyson M

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Posted 22 May 2021 - 08:52 AM

Will those instruments fit in a 10'x14' space? As you know, a deck can be quite the trampoline. That's annoying with a small scope and worse with a large one. Might want to consider a "temporary" support to ground below the instrument pad above. Something like this jack-stand in the picture. It wouldn't be there to support the load, but only to dampen/snuff most of the trampoline effect. Just snug it up enough to achieve that.    Tom

You're right,  the 10'x14' won't work. I need at least 12' x16' doing rough calculations but it's not so simple as I made it out to be.



#7 speedster

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Posted 22 May 2021 - 02:19 PM

Might it be better to pay a nominal property tax and then build on a sound foundation and avoid a slew of potential problems?


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#8 Tyson M

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Posted 22 May 2021 - 04:26 PM

I agree with that sentiment.

 

A solid foundation isn't something I'm taking a gamble on. That's why I scrapped the idea of a deck. I don't like the idea of concrete blocks.

 

For all intents and purposes it's not going to be moved. The skyshed ROR builds on buried patio stones On the ground. My shed will be likely prefabbed into a shop and delivered at site. Perhaps I'll do the same with buried patio stones for it to rest on.

 

So really the only issue is the roof rail posts.  I'm speaking with a contractor now and he figures there are triangle support blocks they can sit in and directly on the ground. Just got to make sure to level it off and it's directly on the ground, which would be solid foundation.



#9 archer1960

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Posted 22 May 2021 - 05:17 PM

I agree with that sentiment.

 

A solid foundation isn't something I'm taking a gamble on. That's why I scrapped the idea of a deck. I don't like the idea of concrete blocks.

 

For all intents and purposes it's not going to be moved. The skyshed ROR builds on buried patio stones On the ground. My shed will be likely prefabbed into a shop and delivered at site. Perhaps I'll do the same with buried patio stones for it to rest on.

 

So really the only issue is the roof rail posts.  I'm speaking with a contractor now and he figures there are triangle support blocks they can sit in and directly on the ground. Just got to make sure to level it off and it's directly on the ground, which would be solid foundation.

And they would likely be able to be tweaked if necessary such as the blocks settling over time.



#10 John Fitzgerald

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Posted 22 May 2021 - 05:44 PM

Pour piers into the ground well below ground level, set the patio blocks onto the concrete piers.  Cover the edges of the patio blocks with dirt.  Hidden supports.  Things that cannot ever be seen won't be taxed.  If there was solid rock four inches down, same thing.  Make your own rock.


Edited by John Fitzgerald, 22 May 2021 - 05:47 PM.

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#11 John Fitzgerald

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Posted 22 May 2021 - 05:59 PM

Tyson,

I have a 16x16 foot ROR.  When we put a 12 inch F/5 Dob and a C14 in it, there is just enough room to be barely comfortable, with both in use.  You will need larger than that, unless one scope at a time is used, and the other strategically parked.  I think you will need 20 feet of length for both scopes to have enough separation, and at least 14 feet of width, preferably, for that Dob to swing 360 degrees, and have much room for the observer.  You really need a slab, or you might find your ROR a haven for rodents, without a means to seal it at the floor against burrowing.   Wooden floors close to the ground have rot problems, and rodents make homes underneath.  I know about that.  My warming hut is on a wooden floor close to the ground.

 

I would not have built my existing ROR without the concrete slab, and if I had to do it over, the warming hut would also sit on a slab.


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#12 Tyson M

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Posted 22 May 2021 - 07:57 PM

Tyson,
I have a 16x16 foot ROR. When we put a 12 inch F/5 Dob and a C14 in it, there is just enough room to be barely comfortable, with both in use. You will need larger than that, unless one scope at a time is used, and the other strategically parked. I think you will need 20 feet of length for both scopes to have enough separation, and at least 14 feet of width, preferably, for that Dob to swing 360 degrees, and have much room for the observer. You really need a slab, or you might find your ROR a haven for rodents, without a means to seal it at the floor against burrowing. Wooden floors close to the ground have rot problems, and rodents make homes underneath. I know about that. My warming hut is on a wooden floor close to the ground.

I would not have built my existing ROR without the concrete slab, and if I had to do it over, the warming hut would also sit on a slab.

Excellent feedback here. I might pull the plug on dual scope observatory. I have room but I don't want a warehouse on my gf parents land for two scopes lol.

I might scale back to just my 25" dob. Keep my 9" achro and mount in my backyard with a tarp over it, bound at the mount with bungee cords or something.

Say just the 25" f5 dob....I think the 12' x 16" would work hey? Eyepiece height of approx 10' at zenith.

I will look into a slab being poured as well. If a structure is over top, it's hard to tell.

#13 John Fitzgerald

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Posted 22 May 2021 - 08:38 PM

Excellent feedback here. I might pull the plug on dual scope observatory. I have room but I don't want a warehouse on my gf parents land for two scopes lol.

I might scale back to just my 25" dob. Keep my 9" achro and mount in my backyard with a tarp over it, bound at the mount with bungee cords or something.

Say just the 25" f5 dob....I think the 12' x 16" would work hey? Eyepiece height of approx 10' at zenith.

I will look into a slab being poured as well. If a structure is over top, it's hard to tell.

Tyson, the swing of that Dob will be about 8 feet.  With a 12 foot wide (outside dimension, I assume), you won't have enough room to swing it around unless it's pointed well above the horizon.  I'd put the refractor in there permanently, and leave the Dob in there, but wheel it out with wheelbarrow handles onto another pad of patio blocks to use.  Observatory for the refractor, storage for the Dob.  With this configuration, you could make a smaller building.

 

You can use concrete board for siding, and extend it to the ground all around, and the slab won't show.



#14 Tyson M

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Posted 22 May 2021 - 08:40 PM

I really like that idea John. The refractor has an arc of about 5 ft. What size would you think would work for this for the shed and then the extension to roll the dob out

#15 John Fitzgerald

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Posted 22 May 2021 - 08:52 PM

I really like that idea John. The refractor has an arc of about 5 ft. What size would you think would work for this for the shed and then the extension to roll the dob out

I think if you made it 12x12 feet it would work fine for the refractor and Dob storage.  You could park the Dob under the parked refractor.  For a refractor, make the walls higher than you would for a Dob, probably 7 feet or a bit more even.  Better wind protection, and a higher park position for the refractor. I would place some well levelled patio blocks far enough outside the door to use the Dob with a minimum of movement.  No use placing it any farther than necessary, as you would probably keep the ep case, etc in the observatory while you are viewing.  Make the door as wide as practical, probably 4 feet wide.  Under and against the bottom of the door, place a big slab of wood to hide the slab, presumably as a door stop for additional security.

 

BTW, your girlfriend sounds like a keeper, at least her parents are. cool.gif lol.gif



#16 555aaa

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Posted 22 May 2021 - 09:40 PM

My pier is just a four foot by four foot concrete pad about six inches thick, with masonry blocks mortared to it. The telescope in my avatar photo sits on that. It’s all up weight is close to a thousand pounds. Eventually it will move but it’s been stable enough to only require realignment once per season. I’m at a semi desert site and being in the middle of a building it’s not really liable to frost heave.

#17 Tyson M

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Posted 23 May 2021 - 07:27 AM

I think if you made it 12x12 feet it would work fine for the refractor and Dob storage. You could park the Dob under the parked refractor. For a refractor, make the walls higher than you would for a Dob, probably 7 feet or a bit more even. Better wind protection, and a higher park position for the refractor. I would place some well levelled patio blocks far enough outside the door to use the Dob with a minimum of movement. No use placing it any farther than necessary, as you would probably keep the ep case, etc in the observatory while you are viewing. Make the door as wide as practical, probably 4 feet wide. Under and against the bottom of the door, place a big slab of wood to hide the slab, presumably as a door stop for additional security.

BTW, your girlfriend sounds like a keeper, at least her parents are. cool.giflol.gif

I've been dating her for 7 years or so hah.

Question: if the observatory is being delivered to me and then roof rails and support beams installed at site, is there a point to pour a concrete pad underneath? I guess it depends how it's built but I'm guessing the shed will be on some kind of skid. So rodents potentially living under it by digging holes in the ground.

#18 John Fitzgerald

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Posted 23 May 2021 - 08:43 AM

You would need to pour the pad first, then stick build the observatory on top of it.  It's much simpler that way, than trying to modify a pre-built shed to have a roll off roof.

 

BTW, I'm helping a nearby friend build a 16x16 ROR this summer. He's pouring the slab first.



#19 dnrmilspec

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Posted 23 May 2021 - 08:53 AM

I've been dating her for 7 years or so hah.

Question: if the observatory is being delivered to me and then roof rails and support beams installed at site, is there a point to pour a concrete pad underneath? I guess it depends how it's built but I'm guessing the shed will be on some kind of skid. So rodents potentially living under it by digging holes in the ground.

7 Years and you are going to build on her parent's property?  Maybe its time......Just saying.



#20 StephenW

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Posted 23 May 2021 - 06:45 PM

In addition to what others have suggested, I'd imagine you would want the wall height for the Dob-servatory to be much lower than for the refractor.

If it was me, and permits, cost etc allowed, I'd build two observatories :), one for the dob with low walls and one for the refractor...
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#21 Cotts

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Posted 27 May 2021 - 12:59 PM

Tyson, I have just begun to imagine a deck for my dob with a removeable "outhouse" cover for it.  Just an open air deck, maybe 8'x8' with a concrete slab/block of some sort to sit the dob on......  I'll be starting thread here on this today.....rather than jack this one...

 

the observatory needs for your two scopes are so utterly different....

 

Dave



#22 Tyson M

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Posted 27 May 2021 - 02:03 PM

I had some amazing PM's with a CN member on details.

I am going to likely go 12x12', approx 7ft high with a 4' door. I'll simply use the observatory only for storage of the dob, not for setting it up.

The refractor is going to be the main observatory scope in the approximate center and I'll put it on a removable steel pier bolted to a buried concrete foundation below the frost line.

The rest is still up in the air. I need a way to shield the steel tracks from snow. I want to overall structure to not to be permanent (besides being bolted to buried concrete I places). So it will probably go on buried patio blocks. It will be arriving by truck prebuilt on everything except the roll off roof extra supports with tracks.

#23 John Fitzgerald

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Posted 27 May 2021 - 02:13 PM

If you change the plans slightly, and go with inverted V tracks and steel V groove wheels, they are more self clearing of snow when you roll them. With garage door tracks, you will need covers of some kind in winter, where you are located.


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