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JamesF

JamesF's observatory build

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I was pondering on usability today.  Fixing the cladding on the piers is quite dusty because of the drilling, but I could put a bin bag over a mount/telescope and tape it completely closed around the top of the pier whilst I'm working.  The question then of course is which telescope do I go for?  I can probably pass on the C9.25 as I mostly use it for planetary and there's not much to trouble it there for the time being.  But the 127 Mak is great for lunar and white light solar, or there's the ST120 with a Herschel wedge for white light solar, and the PST.  Or should I go for the ED80?  I'm not sure that would fit inside a bin bag, actually.  But the Photoline 72ED might.  It's all so complicated!

James

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8 hours ago, JamesF said:

But the Photoline 72ED might.  It's all so complicated!

You need another scope to cut out complicated decision making...?

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10 hours ago, fwm891 said:

You need another scope to cut out complicated decision making...?

I'll pass this information on to my wife.  Please do drop me your contact details.  I'm sure she'll be wanting to get in touch to thank you for your wise words :D

James

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Circumstances have dictated that I shift some stuff out of the workshop and the house, so my first job today was to cut down the piece of worktop that I've been saving for a desk and get that fitted.  It's just resting in place at the moment as it will need some cut-outs making when I get the electrics done.

obsy-build-97.jpg

A NEQ6 has also made its way down from the house even though I have no suitable bolts to attach it to a pier yet.

I then took the circular saw to my son's old wardrobe to make it shorter and less deep and install that in the warm room.  The plan is to have drawers on the left hand side (I have a number of drawers saved from some other furniture) and shelving on the right.  I may well remove the left hand door.

obsy-build-96.jpg

Of course I still have some sort of floor covering to put in the warm room, but for the moment I just had to get this out of the house and I can't put it in the workshop because we need to empty stuff out of the workshop to get access to fix the electrics -- at the moment I'm dragging a 30m extension lead around with me to whichever power tool I want to use next, which is really not desirable.

In the same vein I have a plan for this week to cut down another old wardrobe currently in the workshop and turn it into a cupboard to go in a corner of the scope room.  It's irritating that things have worked out this way, but such is life.  It won't be too hard to work around when I come to sorting the flooring as long as I don't start filling it up with stuff :)

I also refitted the aluminium section in the warm room ceiling today, so I can get on with making up the lighting this week.  Because it involves cutting the strip and rejoining it with right angle connectors I'm going to make it up on the kitchen table when no-one is looking and test it all out before fitting it.

And the last thing I'm going to attempt to make progress with this week is cladding the other piers.

There are a few hours of clear sky forecast this week.  I'm hoping that one way or another I can get a mount and telescope fixed up to use, even if it's just temporary.

James

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Chopped up the wardrobe this evening and moved the pieces I still want into the observatory for assembly.  Amazingly the workshop looks more empty already.

I also found a suitable 10mm bolt and tried my HEQ5 on the finished pier (the pier adaptor I have is reversible and fits a number of different mounts).  Unfortunately the AZ pin that I have doesn't fit very well with the HEQ5.  I might have to make a new one.  Strange that the HEQ5 tripod uses an AZ pin that's part of the tripod head moulding, but the NEQ6 has a screw-in pin.

Anyhow, that's as far as I got before realising that in the thrill of having ten days away from work, I'd forgotten to do the VAT return so I had to get on with that.  Now I'm feeling rather tired and don't want to risk chopping up the lighting strip for the warm room until I'm a little more on the ball.

James

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Struggling not to get very sweary at my father-in-law this evening :(

Came home this afternoon to find that he'd smashed one of the closures I'd put in the openings in the barn (so the swallows don't get in and start nesting in it before we want to start the conversion work on it) by hitting it with the digger.  But all he could actually offer, like some guilty seven year old child, was "It fell out", before walking off to do something else.  How on Earth can you get to your mid 80s and not learn that it's possible sometimes to say "It was my fault.  I wasn't paying attention and I broke it.  Sorry", nor even that when you lie about it (albeit by omission), intelligent adults are going to realise within about five seconds flat?  Anyhow, I shall have to fix that tomorrow.

I thought I'd regain some calm by finishing cutting the timber for cladding my piers, only to discover as I tried to rip the first piece down on the bandsaw that it no longer cuts true.  It actually forces the workpiece away from the fence.  It didn't do that last time I used it.  But guess who has been "adjusting" it since?  How he's managed to get it to behave like that I have no idea.  Grrrr.

Anyhow, I used the circular saw to roughly cut the cladding to size in the end.  I'll need to fix the bandsaw so I can finish it properly.

On the positive side, a compass and some stainless 12mm bolts arrived, so I have temporarily fixed the NEQ6 in position on a pier.  And I also made up the carcass of my cupboard from the bits I cut down from the wardrobe yesterday.

Oh, and the builder had a look around the observatory and was quite impressed, which was pleasing.  He also said that by sheer chance he happens to have the rack and drive gearing from a stair lift at home on his pile of scrap to go to the tip.  But it might well fit rather neatly into the roof space as a means of opening and closing the roof mechanically.  So he's going to stick it in the van and bring it over later in the week.

James

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Posted (edited)

You may get remote roof opening and closing before I do then!! :thumbsup:  Working flat out on imaging rigs ATM...

Edited by Gina

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I need proper electricity first :)  Still just working from an extension lead.

James

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8 minutes ago, JamesF said:

Struggling not to get very sweary at my father-in-law this evening :(

Oh, and the builder had a look around the observatory and was quite impressed, which was pleasing.  He also said that by sheer chance he happens to have the rack and drive gearing from a stair lift at home on his pile of scrap to go to the tip.  But it might well fit rather neatly into the roof space as a means of opening and closing the roof mechanically.  So he's going to stick it in the van and bring it over later in the week.

James

Some compensation for the frustrations with the father-in-law perhaps!

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Just now, Astrokev said:

Some compensation for the frustrations with the father-in-law perhaps!

Indeed so.  And it's the sort of thing that would never have occurred to me as a possible solution.

James

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1 hour ago, JamesF said:

He also said that by sheer chance he happens to have the rack and drive gearing from a stair lift at home on his pile of scrap to go to the tip. 

Don't watch Gremlins - it might give you ideas about the FIL and stairlifts...

 

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Posted (edited)

Two stair lift racks arrived yesterday courtesy of our builder, each in two sections.  The heavier one is solid steel, but may not be long enough.  The other is multiple layers of sheet steel.

obsy-build-98.jpg

obsy-build-99.jpg

The motors and pinion gears will be arriving in a couple of weeks when he's back from doing some work in France.  I suspect the motors will be somewhat over the top for what's required to roll the roof back and forth (though I can't really claim much knowledge of stair lifts), but I can always fit something smaller using the original pinion gear.

None of this is going to happen in a hurry, regardless.  I want to be using it before I start thinking about automation.

James

Edited by JamesF
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I agree - first things first.

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Are you fixing the motor the wall of the obs and have this rack  running on the underneath of the roof?

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2 minutes ago, spillage said:

Are you fixing the motor the wall of the obs and have this rack  running on the underneath of the roof?

That's the picture I have in my head at the moment, yes.

James

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Posted (edited)

Interesting idea about using a stair lift, I imagine a complete one would contain lots of useful bits as they have adjustable eletro' mechanical end stops, decent batteries and remote controls.

The motor may be a bit over the top but no harm in that really, they even have a manual emergency mode that can be operated with an battery drill.

Dave

Edited by Davey-T
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3 hours ago, Davey-T said:

The motor may be a bit over the top but no harm in that really, they even have a manual emergency mode that can be operated with an battery drill.

That's another very interesting bit of information that I didn't know.  Particularly as in this case I have a few cordless drills sitting around that no longer have functioning batteries.  It would be very neat if I can put them to another use.

James

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If you can put motor above the rack on a hinged mounting you will have a  simple drive that won't need any cleverness to adjust the backlash/engagement and if you balance it right in the even of a jam, the gear will ride up rather than stall the motor (although you might want it to adjust it to stall so it blows a fuse if it gets stuck - for unattended operation).

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37 minutes ago, Stub Mandrel said:

If you can put motor above the rack on a hinged mounting you will have a  simple drive that won't need any cleverness to adjust the backlash/engagement and if you balance it right in the even of a jam, the gear will ride up rather than stall the motor (although you might want it to adjust it to stall so it blows a fuse if it gets stuck - for unattended operation).

  A variation of this has the motor and drive pinion on a pivoting plate attached to a fixed wall, with weights and/or springs used to provide engagement force. That makes for fixed wiring but still accommodates inconsistencies in the rack. There are generally three challenges associated with these types of drives. The first is start-up torque. If the motor spins up very quickly, the system can experience very large forces as the inertia of the roof is overcome. A high gear ratio which results in slower opening speed is probably the simplest solution, though in some cases DC motors are used and ramped-up to speed. If the gear drive doesn't allow for back drive (e.g., a typical worm drive), you also have to pay a bit of heed to ramp-down at the other end of travel. With a belt or spur gear reducer, you can probably get away with setting the limit switches such that the roof coasts closed approximately where you want it.

  A second concern is stalling during movement. If something jams, you want to be sure that some mechanism stops the motor before anything is damaged. As Stub noted, a fuse may be sufficient protection. This is always more of a concern with unattended operation since there probably won't be anyone around to hit the stop button if things start going wrong.

  Finally, loss of power or a drive failure needs to be considered. The last thing you want is the roof stuck open as weather is moving in. If there's a mechanism which allows override using a separate motor such as a surplus drill, that's a good start. But again, if there's a worm drive which may jam, you should probably consider options to disengage it entirely. This usually isn't too difficult with a pivoted mount if the contingency is considered during the design phase.

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Another three day weekend, so soon!  Just like buses...

As the poet said, "the best-laid schemes o' mice an' men gang aft agley" and despite good intentions I've achieved very little on the observatory this week.  Work has been sufficiently stressful that were it not for having school fees to pay and suchlike I might well have decided to throw in the towel and get a job as a postman.  Or as a swim teacher.  Hints are regularly dropped by the teachers and staff at the pool where I swim and this week it has started to look very tempting.

Anyhow, I decided this morning to sort out the warm room lighting.  Perhaps it was just as well I'd left it until the weekend given my previous comments.  A certain amount of calm was required as the right-angle joins are not the simplest of things to get to work.  They snap open and closed and have four raised contacts inside that are supposed to fit against the contacts on the ends of the LED strips where they have been cut, but they're actually quite awkward to get seated correctly.  Initially I made up the full run of LEDs and tested them to find that only the first strip worked.  From there it was actually easier to work with the strips "live" so I could see when I had the strips positioned in the joining pieces correctly and snap them closed with a pair of pliers whilst holding everything in position with the other hand.

I also discovered that the joining pieces don't sit far enough back in the aluminium section to allow the diffuser strip to go over the top of them which was a bit disappointing, but I guess I can live with that.

obsy-build-100.jpg

obsy-build-101.jpg

Next I fixed the bandsaw.  Actually, I kind of made things worse before better as I managed to snap the existing blade whilst trying to get it properly adjusted, only to find once I'd removed it that the blade had actually developed a curve across its width.  Quite how you get it to do that I really don't know, but it does explain why it wouldn't cut straight.  At least I didn't break a blade that wasn't already useless.

That done I was able to trim down the ply that I cut a few days back to clad the second pier.  I used a dustbin bag to cover up the NEQ6 that I already have in place.  It actually seemed to go much quicker today than last time, and for a change I didn't kill any drill bits.  I ran out of time on the last side (the one with the access hole to get to the bolt that secures the mount), but nipped out again after dinner and fitted it whilst waiting for the chickens to decide it was bedtime.

So, one more pier to go and I think that should be all the really messy work done.  I do plan to paint the pier cladding, but I think I might leave that for now as I can always lift the tiles around the piers to paint later, and instead think about flooring and finishing the storage so I can properly start on moving kit from the house.

The other thing I have at the back of my mind at the moment are the additional pier adapters that I need.  I think I have some round aluminium bar that is big enough to make one for the HEQ5, but it is quite tempting to sidestep the problem and look at using a brake disc.

James

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Sounds like you’ve been busy. Lighting looks good, but a bit concerned with the issues you had with the corners as I still haven’t bought my LED strips. Looks like you got round the problem though. 

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Yeah, they seem to be working fine now.  Some of it might just be down to manufacturing, to be honest.  I bet a fair bit (if not all) of this stuff is knocked out in factories in China without a huge amount of attention to quality control (given how much it costs, how could you?).

Bending the strips around corners where the strip folds at right angles (such as I have in the walls of the scope room) is a doddle.  It was just making the U shape that meant the more awkward fittings.  It does look like you can get splitters for the controller output though, so in retrospect perhaps I should just have passed on the "U" and just gone for two parallel rows.

James

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Come to think of it, given that the strip is quite flexible, as long as I chose the positioning carefully perhaps I could have just gently folded the strip back on itself and then diagonally to create the right angle turn.  That might have saved a whole lot of bother.

James

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All the strips I've seen also have solder pads every 50mm'ish, so another way to 'change direction' without using iffy connectors, is to solder small jumper wires between pads of the same polarity....

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Yes, that's what I've done in the past.

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