51 replies to this topic

[astrovienna]

Skybox 1.0 served faithfully for eight years, but I finally gave in to the inevitable and got a better mount, and it won’t fit into the old Skybox.  So time to move on.  Skybox 2.0 started construction a couple weeks ago.  I’ve made some fairly good progress, so I figure I’d better get a build thread started before I make too many mistakes that can’t be fixed.  There’s always good advice to be had here.

 

Skybox 2.0 is a 10x12 ROR with two piers, one for deep sky and one for planetary.  That sounds tight, and it will be, but I’ll rarely be inside it, since my house is 20 feet away.  Also, one “benefit” of having terrible horizons – the Hole in the Trees – is that I don’t need to see much of the sky because, well, there’s nothing to see but leaves in most directions.  So after setting both mounts up in my basement for a couple weeks and working out all the measurements, I’m pretty sure the two mounts will see everything there is to see and almost never interfere with each other.  The east pier will have a C11 on a Paramount MX+ (the new mount) and the west pier will have a CPC1100 fork mount on a Milburn wedge.

 

I’m mostly following the SkyShed plan, though I put the foundation on posts in concrete rather than having a floating foundation.  I’ve ordered steel piers from SkyShed, which will go on 16” concrete footers sunk 3.5 feet deep and rising to about 3” below the obs floor.  The footers are my only real worry so far.  While waiting for the piers, I dug the footer holes and put in sonotubes, and went ahead with the rest of the build.  I want to hold off pouring concrete, and setting the j-bolts, until the piers arrive. While in theory I could have made templates for the pier bases and gone ahead and poured the concrete, I’d much prefer to have the actual piers. The chances that my homemade templates would be perfect are very low.  😊  The downside is that cardboard tubes aren’t really supposed to sit in dirt for weeks on end.  But we’ve had a dry summer so far, the obs floor covers the footer holes (I don’t plan to cut the holes open until I’m ready to pour), and until the last couple days (since the walls went up) I’ve been covering the worksite with a tarp.  So hopefully everything stays dry down there.

 

Kevin

Edited by astrovienna, 26 June 2017 - 09:32 PM.

[astrovienna]

The work site, with footers dug.  Why yes, since you asked, 16” x 3.5 feet x 2 IS a lot of dirt!    Especially with a post hole digger.

 

 

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[astrovienna]

Progress to date.  I’ve actually got three walls sided (T1-11) so far, and hope to get the last wall (door) sided in the next couple days.  After that, on to the roof.  I attached the siding with deck screws, and found that T1-11 is a lot tougher than I remembered.  I eventually finally started giving the screws a few hits with a hammer to get them started.

 

 

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[astrovienna]

Floor and wall framing,

 

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[Kokatha man]

...saw this thread - wondered what you had been up to!

[astrovienna]

Hi Mo!  Yeah, between learning the new mount and building the obs, there hasn't been much time for imaging.  And planets have pretty much fled the northern sky,

at least with my limited horizons.  My planetary scope will probably be concentrating on the moon for the next few years.

 

Three walls sided:

 

 

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[astrovienna]

Stupid tool question:  how do I make a 22.5 degree cut across the side of a 2x4?  The view below is looking at the 2" side of the 2x4, so this cut leaves a face that's 3.5" by 3.92".  So far I've just used a circular saw to build this (and a few standard sheds), but it won't make a 3.5" deep cut.  And I'd rather not spend hundreds of dollars on a tool I'll likely never use again.  Any ideas?  Chain saw???  The SkyShed plan calls for 8 of these cuts.

 

 

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[xiando]

I'm not exactly sure I'm seeing the 2x4 properly but if your image is showing the 2" side face-on, and presuming you can't adjust far enough to cut 22.5 directly, sketch the cut profile onto the wood, carefully cut one side, then the other.

 

Or sketch the cut profile onto the wood and use a handsaw.

Edited by xiando, 29 June 2017 - 06:48 AM.

[astrovienna]

Yes, you're looking at the 2" side face-on.  I suppose I could start the cut with the circular saw and speed square, and finish with a handsaw?  That might not be very smooth though.  Maybe you're right, do the whole job with a hand saw.

 

Kevin

[xiando]

Just make sure the saw is sharp. Many of us have an old handsaw, but they're often dull and worn out. 

Edited by xiando, 29 June 2017 - 08:04 AM.

[astrovienna]

How about this for steel roofing?

 

http://www.homedepot...13230/204254799

 

It looks very much like Fabral Grandrib 3, perhaps a private label?  I'd be happy to get genuine Fabral, but there's no dealer anywhere near me.  And I've found very little in the way of instructions to guide me in collecting all the parts I'd need.  Without a dealer to help, I'd have to watch all the Fabral videos and just figure it out.  I've only done shingles before, never metal.

 

For rollers, SkyShed specs these:

https://www.amazon.c...DKIKX0DER&psc=1

with hinges from the same manufacturer:

https://www.amazon.c...DKIKX0DER&psc=1

Knowing nothing about garage doors (except by looking at my own), they look as good as anything else to me, but let me know if you think I should use something else.  I still haven't lined up a supplier for tracks.  BTW, a "vertical" track is what I want, even though it'll be used in the horizontal position, right?

 

Kevin

[burdij]

Home Depot sells a hand miter box by Stanley for $53 that would let you do those 22 1/2 deg. and 67 1/2 deg angle cuts without losing any fingers. I am building a 16 sided base for a circular building that requires 11.1 deg. cuts on the ends of each side face but I am using a 12" power miter box.

[astrovienna]

It’s been very much a 3 steps forward, 2 steps backward process.  I’ve got the walls sided, the roll off rails are up, the gable peaks and runners are done, and the piers are in place.  This weekend I’m hoping to get most of the roof done.

 

[astrovienna]

But each step has had its own challenges.  For example, the mitered cuts on the gable peak were a hassle, as expected.  And those roof runners weigh a TON – probably 80 pounds each, before mounting the rollers.  I’m really not sure how I’m going to lift them into place.  Suggestions?  Anti-gravity?

 

Edited by astrovienna, 31 July 2017 - 10:12 PM.

[astrovienna]

Instead of screw jacks, I used scaffolding jacks.  (I think Terry/dawziecat did the same.)  They’re solid aluminum, so rust shouldn’t be an issue.  I hacksawed them in half first, since they’re 24” tall.  Boring out 10” deep, 1.25” holes in the posts really tested my drilling skills.  I stained the roll-off structure the day I finished it, to help avoid twisted rails.

 

[astrovienna]

The concrete footers turned out fine.  I had planted the sonotubes in the ground weeks earlier but was trying to hold off pouring the concrete until the piers arrived so that I could make a bolt template, but with four days of heavy rain in the forecast I decided not to wait any longer.  Rented a mixer and three strong teenagers, and put 2000 pounds in the ground.  East pier will hold a C11 on a Paramount MX+ for deep sky imaging.  West pier will hold a CPC1100 on a Milburn wedge for planetary imaging and visual observing.

 

 

[astrovienna]

I’ll attach the garage door track one night this week.  One club member mentioned that rain water can run into the obs along the tracks.  Any idea how to avoid that?  He drilled weep holes in his tracks, but I’d appreciate any other thoughts as well.

[saga01]

I cut 6" plastic (PVC?} pipe from Lowes in half, painted it, and strap it over the rails to protect the wood and the tracks.

 

Mike

[astrovienna]

Any practical advice for installing those runners?  They weigh a TON - probably 80-100 pounds each.  The steps in the SkyShed plan to install a runner seem to be:

 

1.  Attach two hinges to the runner

2.  Lift the runner up to the rail and (somehow) balance it in the notch on the roll-off wall, so it's half-in and half-out of the observatory building itself

3.  Insert rollers into the two hinges and the garage door track

4.  Roll the runner back into the obs, and attach the remaining hinges and rollers (how?  I take it you need several people to hold the thing up, or it will just rip off the wall, right?)

5.  When all the hinges are attached to the runner, roll it back to the 3/4 rolled off position

6.  Attach cross pieces between the runners and temporarily nail them into place on the rail.  Then build the rest of the roof.

  

Sounds easy enough once the runners are joined together and nailed to the rails, but steps 2-5 sound like killers.  Any suggestions?

 

Kevin

[astrovienna]

I think I just found a problem.  The design calls for attaching the exterior rails to the interior rails with a 4x4 strong tie.  It says to attach with screws, but the holes aren’t tapered – the screw head would stick out if it’s big enough, or slip right through.  So I used 10d nails, as the strong tie instructions call for.  The bracket and nail heads stick out 3/16 inch from the rail side, which will force the garage door track outward at this point.  I suppose I could ignore this, screw the tracks down and accept a bulge at this point, though a similar but opposite bulge from the other rail will mean the tracks are 3/8 inch closer together at this point.

 

 

What do you think?  Leave as is?  Remove the nails and try to use some kind of screws?  With the bracket, the surface will still stick out at least 1/16 inch.  Cut off the strong tie and try to use some kind of mending plate on the top instead?  (I’m not even sure how I could cut it off at this point, but at least it’s fastened with three more nails from the other side.)
Dang, I’ll never make a living as a carpenter.

Edited by astrovienna, 01 August 2017 - 07:20 PM.

[sewhite]

Put spacers under the track to match, washers may do the trick.

Stan

[astrovienna]

Put spacers under the track to match, washers may do the trick.

Stan

Hey, that should work.  Thanks.  I'll never make a living as an engineer, either!

 

Kevin

[astrovienna]

Actuallly, one concern about that: shear force on the screws. Washers will set the screw heads out a bit from the rails. I was planning to use standard 3.5 inch screws. Strong enough?

[sewhite]

Astrovienna,
I should have said use fender washers between the wood and the rail to space out to match your brackets. This will give a solid surface for the rail to sit on. 3.1/2" long screws are more than sufficient on length, diameter is more of a limiting factor. Use as large as reasonable. The observatory will be great, more observing, less setup.

Stan

[astrovienna]

Or . . . . maybe I'm just worrying about nothing.  Tonight I tested out the brute force approach.  I temporarily attached two of the garage door tracks around the bracket:

 

 

Then I mocked up a runner using a 2x4 with three wheels and hinges.  While there's definitely a bulge in the tracks around the bracket, the runner mock up had no problem at all getting around the bulge.  There's enough play in the wheel stems that the runner just goes right past it.  So maybe I'm just obsessing more than most folks here do - though my experience in the observatories forum suggests that probably is NOT the case! 

 

Thanks for the help.  Now, how about some antigravity devices to lift the real runners up into position? 

 

 

Kevin

Edited by astrovienna, 02 August 2017 - 09:38 PM.