Observatory Progress

[Tony G]

Mark, (or any else interested)

Whilst out on Saturday I spotted a real bargain which was a 240v cable hoist, and didn't know if it could be utilised in the opening and closing of the Obs roof.
There was about 20 or so of these at £10 each, as they are trying to get rid of old stock (Lidl's) and as you see from the link below, someone is trying to cash in on them.
If anyone would like me to pick one up (whether you have an Obs or not) just let me know.Postage and Packaging £46.50 Free P&P, which means you'll get it the next time I see you. 

http://www.ebay.co.uk/itm/Parkside-cable-winch-garage-hoist-/111098061616?pt=UK_Home_Power_Tools&hash=item19ddf5e330

Tony G

[MarkS]

Meteorologists say we are in for a decade of wet cloudy summers:
http://www.independent.co.uk/news/uk/home-news/stand-by-for-another-decade-of-wet-summers-say-met-office-meteorologists-8663024.html

They blame it on the "Atlantic Multi-decadal Oscillation".  But I think I can guess the true reason.

Really sorry about this, folks 

Mark

[MarkS]

Hoping to get the "ventilation ducts" ready for the concrete tomorrow (Saturday).  First need to cut them down to size and then erect temporary framework to hold them in place and vertical.

I bought a 2nd hand NEQ6 mount this week (the new style with the dual Vixen/Losmandy saddle and the extension bar for the weights) to sit alongside my existing EQ6.

Last weekend, on the Jodrell Bank trip, someone asked me about how the roof rolls.  
The answer is that it sits on two giant "inline roller skates":


Here's another view, sitting on the angle iron "track" with the roof trusses screwed on top:


The nylon wheels are good quality with proper bearings.  A set of 4 has a load capacity of 600kg.  I've used 6 wheels to build in some safety margin because  I reckon the roof weighs around 700kg.

[Rocket Pooch]

Wow that roof is heavy, I can lift mine up, I hope the wood does not split where the bolts go through if it really is 600kg, might be worth putting some string reinforcement around the bolt holes if it is.

[MarkS]

I hope the wood does not split where the bolts go through if it really is 600kg, might be worth putting some string reinforcement around the bolt holes if it is.

I'm not sure that string would help much

[Mike]

Mark what keeps the wheels from rolling off? Do they sit in a track?

[MarkS]

A 40mm angle iron track ("L" cross section).

[mickw]

It looks like the rollers are set about 5' apart and the "axles" for the rollers have about 3" of timber (twice) above them which would only put around 70-75 kilo load  on a 5' span (of effectively) 4" x 3".  I did have my doubts but it does look strong enough.

What will stop the rails moving apart or closer ?

Apologies for resorting to maths 

[MarkS]

Yes the wheels are approx 5' apart.

What will stop the rails moving apart or closer ?

The angle iron is screwed down (I drilled holes through it).

Or were you asking something different?

[mickw]

Sorry I meant the rails the wheels are fixed into

[MarkS]

The rails holding the wheels are screwed to the roof trusses.  So their distance will be always fixed.

[mickw]

Doh
Obvious really 

[MarkS]

Today's gusts of wind succeeded in sliding the roof backwards, since I haven't yet fitted the internal locks.  It may weigh 600kg or so but it moves relatively easily.  I think I need to uses wedges for the wheels - at least until I've fitted the locks.

[Rocket Pooch]

Hi Mark,

The string bit is called whipping, when you have the grain going left to right and a whole through the middle you can whip either side and dope it and it becomes incredibly strong, like the old planes in ww1 and before.

I have fixed many wooden garden chairs doing this when the bolts holding the folding legs together cause a split.  You glue and whilp and bingo all done.

Chris

[MarkS]

Right - now I understand!

I remember my dad doing similar on camping equipment.  But it's a long time since I've seen it done.