Housing a big SCT - and a question.

[ollypenrice]

I have the slightly daunting task of housing a newly acquired 14 inch SCT, the late Aan Longstaff's mighty Meade LX200. It will be great to have my old friend's instrument here for all to enjoy but it is on the intimidating side! You wouldn't call it portable. More like 'Grab 'n' stay.'

I'm also one for working with what I have, so I have an under-used 'sentry box' roll off already in place and I have an aluminium pier adapter plate which does not, on closer inspection, seem to be designed for this scope. However, it's flat and round so I'll use it. The scope will be for visual use and in Alt Az confuguration so I need a level base for it. Hmmm...

So I went to the builders' yard and bought four 20cm high cast circular concrete pillar segments intended to make presentable pillars. I've epoxy-bonded these to the floor of the observatory and and to each other and added some rebar, also bonded into the floor, which rises up into the void in the pillar. Tomorrow I'll fill this with concrete. (Giving the interior a good wetting first.)

I've also bought some threaded bar to attach the top plate to the concrete pillar. I need access from beneath so I'll be limited to 5x10mm bars. They don't need to be much higher than the top of the concrete - just enough to get a spanner in to hold the mount down with its centre bolt.

Now, should I try to embed the threaded bars, already bolted to the top plate, as I fill the concrete or should I fill the concrete then drill it to accept the five bars and epoxy the bars in later? The latter sounds easier, I think.

I'd take a pic or two but it's in the thirties outside and I'm too tired!

Olly

[Davey-T]

I used the epoxy route recently very easy as long as you choose the right system that mixes it as it comes out of the nozzle.

Mind your back 

Dave

[jACK101]

Olly,

 

I have just completed a similar exercise. I am using a car brake disc, Mercedes no less. Not because it was Mercedes, but because I needed a 300mm diameter disc. (£20 on Ebay)

 

I drilled out the five existing holes to 16mmm to match the screwed rod I was planning to use, (screwfix) then used that as a template to make 2 identical plates in plywood. I bolted one plate to the bottom of the five rods and the other near the top, but below the finished level. I dropped this assembly into the shuttering for my concrete and poured the concrete. The plywood kept the bars parallel and all I had to do as the concrete was being poured was to ensure that the rods remained as vertical as I could manage. In any case I can adjust the brake disc later to make it as horizontal as possible. The nuts on the immersed plywood templates I think will also make it more difficult for the rods to be pulled out of the concrete.

 

I hope this helps.

 

Jack

 

That is as far as I have progressed, the rest of the obsy has still to be built.

[barkis]

Is the 14" on a Wedge Olly? I assume it is, so perhaps you can report 
on how you find the setup as an Imaging rig. I've heard some disparaging comments 
about the wedge being unsuitable as a guiding platform for AP. 
I did own a 12" LX 90 for a while, I loved for Observing, but never got to demonstrate it's 
Imaging capability., and I don't think the LX 90  Is as good as the LX200 from an Imaging POV.

I'm assuming you intend doing some Imaging with it, I may be wrong, as
you already have very a capable Imaging base at your site in the Mountains.

 

[AKB]

10 minutes ago, barkis said:

Is the 14" on a Wedge Olly?

It seems not...

1 hour ago, ollypenrice said:

The scope will be for visual use and in Alt Az confuguration so I need a level base for it.

 

[Pig]

I would screw a few nuts onto the threaded bar first, leaving gaps of course, and then concrete them in. This will give something for the concrete to grip onto ?

[ollypenrice]

11 minutes ago, Pig said:

I would screw a few nuts onto the threaded bar first, leaving gaps of course, and then concrete them in. This will give something for the concrete to grip onto ?

Good thinking. Thanks.

39 minutes ago, jACK101 said:

Olly,

 

I have just completed a similar exercise. I am using a car brake disc, Mercedes no less. Not because it was Mercedes, but because I needed a 300mm diameter disc. (£20 on Ebay)

 

I drilled out the five existing holes to 16mmm to match the screwed rod I was planning to use, (screwfix) then used that as a template to make 2 identical plates in plywood. I bolted one plate to the bottom of the five rods and the other near the top, but below the finished level. I dropped this assembly into the shuttering for my concrete and poured the concrete. The plywood kept the bars parallel and all I had to do as the concrete was being poured was to ensure that the rods remained as vertical as I could manage. In any case I can adjust the brake disc later to make it as horizontal as possible. The nuts on the immersed plywood templates I think will also make it more difficult for the rods to be pulled out of the concrete.

 

I hope this helps.

 

Jack

 

That is as far as I have progressed, the rest of the obsy has still to be built.

More good thinking. I'd given plywood templates a thought myself. (I was casting a nafarious eye on a load of pizza platters I cut last year but I'm always fearful of Madame finding out...)

31 minutes ago, barkis said:

Is the 14" on a Wedge Olly? I assume it is, so perhaps you can report 
on how you find the setup as an Imaging rig. I've heard some disparaging comments 
about the wedge being unsuitable as a guiding platform for AP. 
I did own a 12" LX 90 for a while, I loved for Observing, but never got to demonstrate it's 
Imaging capability., and I don't think the LX 90  Is as good as the LX200 from an Imaging POV.

I'm assuming you intend doing some Imaging with it, I may be wrong, as
you already have very a capable Imaging base at your site in the Mountains.

 

No wedge, Ron. Strictly Alt Az and strictly visual. One of my worst mistakes was trying to image on a wedge mounted Meade, closely followed by the mistake of de-forking it to try it on an EQ. I want to use Alan's scope for what it's good at, which will be giving GoTo convenience at a serious aperture with the comfort of contorsion-free viewing positions. I ruined a perfectly good LX200 ten years ago. I won't do it again!

Olly

[Stub Mandrel]

I would drill and epoxy in the fixings or use expansion bolts.

[Alien 13]

I am sure it will be a great visual scope Olly but it will still make a killer Planetary/Lunar imaging rig without changing anything.

Alan

[ollypenrice]

33 minutes ago, Stub Mandrel said:

I would drill and epoxy in the fixings or use expansion bolts.

I fear expansion bolts might burst the top of the pier because they'd be close to its circumference and concrete is only strong in compression. But I'm a huge fan of Fischer epoxy. It's almost supernatrually strong. I think you're right. Cast it then drill it.

Olly

[Peter Drew]

30 minutes ago, ollypenrice said:

I fear expansion bolts might burst the top of the pier because they'd be close to its circumference and concrete is only strong in compression. But I'm a huge fan of Fischer epoxy. It's almost supernatrually strong. I think you're right. Cast it then drill it.

Olly

I would "double" drill it as in a smaller drill bit first. Hammer action drills are a bit like road drills, the vibration could cause a split.   

[barkis]

2 hours ago, ollypenrice said:

Good thinking. Thanks.

More good thinking. I'd given plywood templates a thought myself. (I was casting a nafarious eye on a load of pizza platters I cut last year but I'm always fearful of Madame finding out...)

No wedge, Ron. Strictly Alt Az and strictly visual. One of my worst mistakes was trying to image on a wedge mounted Meade, closely followed by the mistake of de-forking it to try it on an EQ. I want to use Alan's scope for what it's good at, which will be giving GoTo convenience at a serious aperture with the comfort of contorsion-free viewing positions. I ruined a perfectly good LX200 ten years ago. I won't do it again!

Olly

, I fully understand Olly, I'm also at an  age where comfort at certain body distortions are to be avoided at all costs,
It's not very nice inducing severe cramps in the Dark.   I'm sure you'll enjoy the 14",  and the easy acquirement of the targets you seek.

[barkis]

3 hours ago, AKB said:

It seems not...

 

How did I miss that, I must pay more  attention .