JamesF's observatory build

[Rusted]

16 minutes ago, Dr_Ju_ju said:

define work.....

That which one would otherwise avoid were one not recompensed in kind, in keep, in rations or in tokens to the local, monopoly food store.

[JamesF]

14 minutes ago, Craney said:

Your shadow looks like you are enjoying a fine malt whiskey, as you survey the task ahead....

It does rather :D

James

[Stub Mandrel]

2 hours ago, Dr_Ju_ju said:

define work.....

Expending energy to move the point of application of a force.

Sounds a waste of time. Probably best avoided.

[JamesF]

Well, with the tiles for the scope room floor arriving today, what's a chap supposed to do?

Not leave them sitting there in the packaging, certainly.  I spent a good half hour just playing with arrangements to try to minimise the cuts around the piers.  I even thought about offsetting rows from each other, but the edges of the tiles are effectively "keyed", so that isn't possible.  In the end I came up with something that meant two of the three piers were fairly straightforward to work around.  The last requires a hole to be cut from the middle of a tile, or I accept that there will be at least a couple of joins that aren't keyed together.

A couple of hours or so later, here's what I have:

That last tile standing up is the awkward one to fit around the pier and it is the last one I have.  There is no room for error.  The waste (from two dozen tiles) is what's lying on the floor.  In fact that's not entirely all waste, as I have a couple of little bits still to fit around the trunking and on the right hand side of the closer pier.  It was 10pm and I was feeling a little tired, so I decided I'd leave the complicated bit until tomorrow.

Overall I'm very pleased with them.  They're comfortable and warm underfoot (I was working barefoot again) and very easy to work with.  They cut very easily with a sharp knife and can be marked with a pencil when measuring them up.  I was a little confused initially by the fact that the edging pieces didn't all match.  They are one of two shapes and won't fit along an edge together.  It's necessary to stick with one of the edges or cut a little piece off the second so it matches.  Hardly a big problem.  They were really quite smelly when I opened the packaging too, but either that got better during the course of the evening or I got used to it

I have cut the tiles to fit a little more snugly than people have recommended.  As I don't really know how much expansion there will be over the area I have I decided I'd leave a small gap and if I need to take off a little more that won't be a problem.

Also arriving today were the "feet" for the posts to support the ends of the roof rails.  They're basically a U-shaped bit of galvanised steel plate to hold the end of the post with a short section of rebar (also galvanised) welded to the bottom.  The rebar just goes into a bit of concrete in a hole in the ground.  I'll take a photo when I get around to fitting them.  My cup truly runneth over as that wasn't even the end of it.  A new (to me) PSU arrived courtesy of another SGL member to replace my old Maplin XM21X that died a while back.

I was hoping to get the power supply plugged into a mount and sort out a telescope to do a little lunar viewing tonight and perhaps even some imaging, but tiredness has caught up with me a bit.  Saturday after next is the first anniversary of breaking ground on this project though, so I'd really like to have an opportunity to use it by then.

James

[Astrokev]

Looking really good James. It feels good to get the flooring down doesn't it! Looks like you've done a great job.

The post support feet sound a great idea. I've seen these in a new housing estate near to where I live, supporting the posts used to construct front porchways. I wish I'd used them for my posts now, mine being embedded in concrete. I've resorted to painting the bottom of my posts with about half a gallon of creocote, so hopefully I shouldn't have anything too much to worry about regarding risk of decay!

[JamesF]

It does feel as though it's made a big difference even though there's still a fair way to go.  Must get on with the warm room floor now.

James

[Stub Mandrel]

I have thsoe in my workshop. they make prolonged standing much more comfortable.

[Bukko]

Impressed with the flooring James.

In fact, impressed with the whole build. Epic project to take on and build from scratch.

Did you manage to fit the last couple of pieces? I used similar on my old Skyshed, it really helped and is much kinder to an EP if you drop it. If you are still struggling to cut to shape the last few pieces, do you have any offcuts you can use as a template?

Good luck,

Gordon

[JamesF]

Thank you, Gordon.  I fitted the last pieces tonight, fortunately making no errors in the process   Very happy with it.

I know I'm a long way from finished, but I need to give some serious thought to using it now, and what really needs to get done for that to happen.  I can probably live without the warm room being finished during the summer for example, so I don't really need to prioritise that though it might be handy for hiding from the Sun to do some solar imaging.  The end flap on the other hand really needs finishing off and some sort of mechanism to hold it in place when closed, which may just actually be a couple of bolts into the roof somewhere.  I need a drip bar over the flap, too, as I'm relying on an untrimmed section of membrane to stop any rain blowing in and that always catches on the flap when I close it.  With a bit of protection from dew I can probably use a couple of trailing sockets to provide power to the lighting and for a mount.  And I might as well use up the materials I have already bought so I don't have to store them any more.

Need to start another list, I think.  Or at least to re-prioritise the one I already have.

James

[Astrokev]

Re: the discussion a short while ago about floor tiles expanding, or not....

I said my tiles are laying completely flat and show no obvious sign of expanding. This statement clearly annoyed the observatory gods, as today I did some solar with a good friend. Once in the sunshine, the floor tiles buckled up like a bucking bronco. Hmm, me thinks I’m going to need to trim some off the edges!

[JamesF]

Just ordered a strap from ebay for lowering and closing the flap, as Alex had posted that he'd bought one some time back.  You do not want to search ebay for "drag strap".  Just trust me on this :)  Well, ok, you might, but only if you're Charles during the week and Chantelle at the weekends, if you get my drift...

James

[Davey-T]

15 minutes ago, JamesF said:

You do not want to search ebay for "drag strap".

Or rubber boots 

Dave

[Yawning Angel]

9 hours ago, JamesF said:

You do not want to search ebay for "drag strap"

So, I checked my ebay history....it's a pull strap, sorry! Link for anyone looking for similar DOOR-PULL-STRAP (Sorry it's too late to save your eyes, James!)

[JamesF]

The last pier adaptor arrived today (from another SGL member) so I fitted that this evening.  This is for the HEQ5 and it's the same as the one @StaceStar is using.  It doesn't come with an alt-az pin so I was hoping to do the same as StaceStar has done and file some flats on a length of M10 thread for the adjusters to push against.  It's not going well, though :(

The adjusters work fine against the pin, but the pin can rock slightly in its threaded hole (not unsurprisingly), which means the mount can still shift position with the adjusters locked up tight.  The obvious solution is to use a locknut as the NEQ6 does, but the HEQ5 adjusters are so close to the body of the mount that a locknut fouls the body.  I even tried filing the corners off the nut (I have some wall-drive spanners so it's not a problem to do it up even without the corners), but there was still insufficient clearance.  I suspect the clearance is only a couple of millimetres, which isn't really enough for a nut of any sort.

At the moment the only simple solution that occurs to me is to see if I have any M10 T-nuts and attempt to use a piece of the sleeve of the nut as a locknut, or grind off most of the "T" and do the same.  Perhaps I'll think of something else overnight.

Having decided to leave that whilst waiting for inspiration to strike I varnished most of the warm room floor and hunted down some trailing sockets to use for temporary power.  Now I either need to make sure I have a laptop set up with all the necessary software to control the mount or to find a handset.  I know I have one somewhere...

James

[Davey-T]

Sorry, do you mean you filed flats all the way including the thread ?

A good wrap of ptfe tape may fix it or of it's going to be permanent some Araldite.

Have to edit your signature soon 

Dave

[JamesF]

I filed flats on the bit that sticks out.  The thread is still pristine where it screws into the plate.  PTFE has to be worth a try given that it's so easy to do.  I could live with Araldite, too.  It is intended to be pretty much permanent, but it wouldn't be too hard to remove the peg even if it were glued in.

Perhaps it's worth trying a few different bolts, too.  It may be that the thread isn't particularly well-formed on what I have now and there's more slop than I'd expect as a result.

James

[Swoop1]

Is there clearance underneath to tighten a nut against the bottom of the plate to put the tension into the pin you need?

[JamesF]

2 minutes ago, Swoop1 said:

Is there clearance underneath to tighten a nut against the bottom of the plate to put the tension into the pin you need?

No, unfortunately not.

James

[Swoop1]

1 minute ago, JamesF said:

No, unfortunately not.

James

Foiled! Screw through the adapter and against the pier top to tension?

[JamesF]

Just now, Swoop1 said:

Foiled! Screw through the adapter and against the pier top to tension?

That's worth a try, even if I have to put a bit of steel plate underneath so it doesn't grind into the face of the block.

James

[Yawning Angel]

I suggested a stud connector to Stacey, but maybe, from your description, there isn’t the clearance to fit it?

Another option is to grind a point on the bolt, like a grub screw, and let it bite into the aluminium bottom of the hole?

[Swoop1]

29 minutes ago, JamesF said:

That's worth a try, even if I have to put a bit of steel plate underneath so it doesn't grind into the face of the block.

James

Whatever you do, you've got this far on your build- you'll think of something👍

[JamesF]

I suspect there will not be room for the stud connector given my trials and tribulations this evening.  Also I think the cast alt-az pin on the tripod head has to slope away from the inside of the mount body to get clearance which may make it even more awkward.  It has to be worth a try though.  It may be that the connectors in question are quite slim.

I'm pretty sure the hole goes all the way through rather than being blind, so locking it against the aluminium isn't an option, but doing as Swoop1 describes above might well be.

The absolute fall-back position is that I find a bit of 10mm or 11mm square bar, turn one end down and cut an M10 thread on it, but I'm not sure cutting the thread so the bar will be in the correct orientation when it locks up is within my capabilities.  Perhaps starting with larger stock, cutting the thread and then facing the top to be square would be easier, if more time-consuming.  I really need the thread to come quite tight up to the undercut, too.  I'm not sure I have suitable dies for that.  Have to have a look tomorrow.

James

[DaveL59]

rather than epoxy as was suggested earlier, some loctite blue threadlock may help? At least you'd be able to undo it later if you needed to tho I can't say the mechanical force acting to rock the pin wouldn't also work it loose over time

Edited May 15, 2019 by DaveL59

[Davey-T]

We use Loctite 55 ptfe cord, does a better job on threads.

Dave