59 replies to this topic

[astrovienna]

I can’t tell you how many times today I said to myself what a harebrained idea this observabox thing is, and how it’s never going to work, and how I’m an idiot for trying this. But at the end of the day we have a “pier” and top plate in the ground with five bags of concrete. We’ll see.



The pier assembly is four 4x4s bonded with construction adhesive and lagged together at two points in two directions. The top plate is three sheets of 3/4 plywood, fastened with the rest of the construction adhesive.


Here’s the location. Note the perfectly good, yet doomed, dogwood cowering over the work site. This tree was all rotted out at the base and limbs when we moved in. Yet here it fluorishes, 16 years later. Note also the picket fence, which will hopefully be taller than the finished observabox.

The hole was about 45 inches deep when I stopped. Hard to go much deeper. Actually, digging the hole was surprisingly easy. I actually thought about renting a posthole digger, but I realized I would do far more harm to my back getting the digger in and out of my car than simply digging the hole myself. My yard is notorious for big quartz rocks, but there were none in the hole. An auspicious start. I put some gravel and a large rock at the bottom as the “footer” for the pier.


Here’s where it got tricky. My single top plate approach minimizes the height of the assembly, but requires an atypical attachment. I used 3/8" x 4" hanger bolts, which are screw threaded on one end and machine threaded on the other. I ratcheted them in by putting three nuts and a washer together. Then I drilled the top plate, with a recess for each hanger bolt to hold a nut and washer. I’ll tool the top plate tomorrow for my Celestron wedge.


And here is the “pier,” all eight inches of it, with the last bag of cement poured in just after dusk. There was only one D’OH! moment. It was when I discovered that, despite carefully taking magnetic declination into account, my pier was lined up 15 degrees off true north. Remember how some folks note that steel can throw off a compass? D’oh! I don’t think it matters, since I won’t be tooling the top plate until I can line up on Polaris anyway. It will just look a bit odd. If that’s the worst that happens with this project, I’m golden.

Advice is welcome!

- Kevin

[astrovienna]

Post deleted by astrovienna

[andyschlei]

Kevin,

It looks good so far! Anything to avoid the set-up / tear-down labor and reduce the marginal cost of observing. And your experience with the mount and north has me feeling good about picking a pier design that didn't require north alignment for setting anything in concrete.

For posting pictures, if you get the url with Firefox's "copy image location" option when your mouse is floating over the image and use that for the image url, it should work.

Clear skies,

--Andy

[Chris Schroeder]

Looking good Kevin

[astrovienna]

Progress continues on the Absurditory. Tomorrow I hope to frame out the roller box. I laid out the track yesterday:



On Sunday night, there were enough holes in the clouds that I was able to set up the scope and check polar alignment. As expected the pier is about 15 degrees off true north, but I just shifted the hole alignment on the top plate, so no big deal. I had the scope setup just long enough to realize how very, very cool it will be to have a permanent setup.



Then I hoisted the scope back up on to the observadolly for what may be the last time, and rolled it back into my shed. I'll miss rolling the old observadolly around my yard.

Not!!!

- Kevin

[mtb.daily]

Kevin;


Very cool idea...

-Jerry

[astrovienna]

Kevin;

Very cool idea...

-Jerry

Thanks, Jerry. So far I'm spending way more time thinking about this than actually building it. Trying to keep the box small (a "low-observable" observatory) has me constantly rechecking my figures, so as not to wind up with a box that is TOO small.

- Kevin

[mtb.daily]

Kevin, your very welcome.


I am gonna watch this thread very closely as I have contemplated building my own 'ObservaBox' but was concerned about a number of issues such as size (to small and its a waste, to big, well then I might as well use a full shed).

Keep the pics comming.

-Jerry

[roscoe]

Hey Kevin, Looks great so far!!!!! So you could just cut the top plate on the pier round, and nobody but you would know the difference.......and if they did, you could tell them it was a nod to magnetic north........ Hey, you're an astronomer, they'll believe you!!!! Russ

[roscoe]

Wow, suddenly I clicked on this thread and got a whole bunch more photos and seemingly some different text! I never will understand these durn computer-thingies! So an idea that just occured to me: If you're thinking of any wiring that goes to your house - power or whatever, you might consider burying some plastic electrical conduit (the gray stuff) with an end that rises up right beside your pier. If you are thinking that too, I can give you some suggestions.... (I'm a carpenter, by the way)
Also, that dogwood tree looks very diseased and close to dead to me, jeez, it doesn't even have any leaves left! I think you ought to cut it down before it falls right over and squishes your new observatory!! Or grows some more leaves so you'll get to thinking it's still alive..... (And you can tell your wife I said so, so it's not your fault if she thinks it's a bad idea................. ;-)

[astrovienna]

I edited the thread to fix the problems with the pictures (thanks, Andy! didn't know FF did that)

A carpenter! I could use one of those! I have been thinking about power, although for now I was just planning to run an extension cord to a nearby outdoor receptable that powers a sump pump. If I dig in a line now towards that receptacle, I figure an electrician will be able to tie it in later, right? But where would I put the outlet? The pier is only eight inches high, so I think it would need to be up on the plywood deck that will run between the runners. Eventually I also would like to run data lines to the house (about 20 feet away).

As for the dogwood, it's going. That will be nothing compared to the huge tulip poplar that I had taken out a few weeks back. I feel bad about that one - carbon guilt - but we do have over a dozen more where that one came from. The Hole-in-the-Trees is a bit bigger now, but it's still just a hole.

- Kevin

[astrovienna]

The view from Day 6:



You can see some blocks attached to the left ends of the runners. To lock the box, two pins (really 5" carriage bolts) drop through holes in each arm of the roller frame and into the blocks. It's simple, but pretty solid. When the walls are ready I'm going to add angle iron at the bottom edges that will hook under the runners and under a crosspiece at the rear of the box. Hopefully that will prevent derailment in the event of kid crashes.

Here it is with the box rolled back (and before I added the frame locks and the roof):

http://lh4.ggpht.com...40/IMG_2632.jpg

I actually have a bit more than this done now. I've got tar paper on the roof, and have cut out all four walls. But it was dark by the time I finished today, per usual, so I don't have an up-to-date picture.

Only one D'OH moment the last few days, when I discovered that my box frame was 3/4" too wide for the runners. No idea where I calculated wrong, but it was pretty easy to fix. My real challenge has been getting the tops of the front and rear walls to match up with the slant of the roof. There must be a trick to this. In my case, the trick will be using quarter round trim (shoe molding) to hide my incompetence. Ah, to be a carpenter like Russ!

I'm going to make a really big push tomorrow to try to get the scope in the box by tomorrow night. It's a lot, but without too many d'oh moments I might have a chance. Wish me luck.

- Kevin

[4Texans]

Kevin,

Looking good. Looking forward to seeing the finished product, and getting a first light use report.

Jeff

[Chris Schroeder]

I'll second what Jeff said

[astrovienna]

Thanks, Jeff and Chris. Turns out I won't get to it until tomorrow, because the rain we were supposed to have gotten last night waited until today. Rain until sunset. So tomorrow will be the big push instead. I'll keep you filled in.

- Kevin

[Odin]

Kevin.... Excellent Idea..... Any Dimensions you can give would be appreciated.

[quantumac]

I'd be concerned that the scope is so close to the ground. The temperature differentials might be a problem. My telescope is about six feet off ground level and I still often deal with shaky seeing (probably because I'm in a valley...)

[roscoe]

looks great, Kevin!!! Russ
PS the skill of a good carpenter isn't building it right the first time, it's figuring out a good way to fix the d'oh moments.........

[astrovienna]

The results of the weekend's work:
The box in the closed position
The box in the open position

So you can see I didn't hit my goal of getting the scope in the box in one day. Shingling took way longer than I expected. Lots of shingles to cut when your roof is only 48" long. And getting the angle irons (these are bolted on to the back side of the east and west walls and "grab" the underside of the rails when the box is subjected to lateral forces - you can just make out the bolt heads in the first pic) to match up and not bind on the rail bottoms was a challenge too.

The big tasks remaining are, first and foremost, to stain and waterseal the beadboard. I left a beadboard scrap out in the rain the other night and the next day it looked like a pretzel. So the box is covered with a tarp until I can get it sealed. Then I need to get the plywood deck between the rails around the pier, and finish tooling the top plate for my wedge. Trim and other little details after that. But it's raining now until at least Thursday, and I'll be away next weekend. So it might be a week or more before there is much visible progress.

I could really use some advice. The door isn't working out. You can see my plan is for a single piece hinged at the bottom to the first rail crosspiece. I chose this because it seemed to offer the best seal against rain, and provided a very clean look. But it's bowing outward on the northwest corner (closest to the camera) as you can see in the first picture, and even with the corner trim pieces I'll add there might not be a tight seal there. Right now the door bracing is 1x4, which even though it's PT is surprisingly soft and flexible. So I'm going to replace it, maybe even with 2x4, and hope that will pull the door straight. If that doesn't work, I'll probably have to go to a conventional double shed-style door setup, which I don't think will be as watertight. (On the other hand, there is less risk of me stepping on it in the dark!) Any advice?

Odin - I'll try to get more exact dimensions later, but the clear space inside the box is about 34H 37L 26W. The goal was enough to hold a C11.

Quantumac - I didn't realize seeing was worse close to the ground. I'll have a plywood deck beneath the scope itself, so maybe that will help some.

- Kevin

[bdjeep]

Kevin,

Looks great. I like the idea.

Based on the overall size and shape, I suggest you name it "The Doghouse Observatory."

[b1gred]

I could really use some advice. The door isn't working out. You can see my plan is for a single piece hinged at the bottom to the first rail crosspiece. I chose this because it seemed to offer the best seal against rain, and provided a very clean look. But it's bowing outward on the northwest corner (closest to the camera) as you can see in the first picture, and even with the corner trim pieces I'll add there might not be a tight seal there. Right now the door bracing is 1x4, which even though it's PT is surprisingly soft and flexible. So I'm going to replace it, maybe even with 2x4, and hope that will pull the door straight. If that doesn't work, I'll probably have to go to a conventional double shed-style door setup, which I don't think will be as watertight. (On the other hand, there is less risk of me stepping on it in the dark!) Any advice?

Have you thought of using a "Z-Brace" on the door? That is put a strut across the top and bottom, with a like piece diagonally between them. Then I you need to apply tension stress to it, you put a piece of all-thread with a turnbuckle in the middle between the opposite corners...

[Odin]

Kevin..Thanks for the Rough Dimensions.... Looking GREAT So Far... This Project of Yours is Very Inspiring.

[astrovienna]

Kevin,

Looks great. I like the idea.

Based on the overall size and shape, I suggest you name it "The Doghouse Observatory."

Yes, plenty of amusing comments already from my wife and kids. But I think Doghouse Observatory is already taken on this forum, for another reason - he often wound up in the "doghouse" for spending too much time on astronomy.

- Kevin

[astrovienna]

Hi Randy: I'm not sure how the turnbuckle idea would work. If I'm following correctly, a turnbuckle arrangement - like I have on the screen doors on my porch - will pull a door frame back into square. But the problem with my box door isn't that it's out of square, it's that it is bowing outward away from the box. I'm not sure how i can tension it back into shape, but if I'm missing something by all means let me know!

- Kevin

[bdjeep]

Yes, plenty of amusing comments already from my wife and kids. But I think Doghouse Observatory is already taken on this forum, for another reason - he often wound up in the "doghouse" for spending too much time on astronomy.

Ahh...I wasn't aware that the name was taken already. I believe I've been in the "astronomy doghouse" on several occasions myself.

Keep us updated on the build. It's coming along nicely.