nightvision

Just returning to Astro and this deep galaxy hunting is inspirational!

Really impressive, what camera are you using? .... Just found it in another post SX Ultra.

This explains them very well: https://www.designingbuildings.co.uk/wiki/Breather_membranes_for_buildings

That's the thing; when the designer and builder is the same person the whole project becomes organic/dynamic, it happens so often... my wife just calls it 'over-engineering again'. I call it 'optimisation that delivers results and motivational energy' (how noble). ? oh yes and more work and more expenditure...? Good luck with your obsy trials and tribulations..

! Yikes sorry I mentioned it, seems you have enough on your plate with this impressive build. If you go ahead you could just float the osb edges and put some supporting wood behind the seams, the structure looks solid enough.

This loglap seems good value and is unlikely to come apart like shiplap. Loglap at £1.30 a metre: https://www.ebay.co.uk/itm/100mm-x-22mm-TREATED-SHED-TIMBER-CLADDING-LOG-LAP-GRADE-A-SEE-POSTCODES-/272755487107?_trksid=p2385738.m4383.l4275.c10&var=571890564978

It can be quite alarming seeing seasonal daylight appear between cladding boards or via knot holes! You could take the cladding purchase off the critical path; separate aesthetics from structure and get your obsy operational by sealing the whole structure in 9mm exterior shutter-ply (only £14.40 for 2440x1220 sheets). More stable than ship-lap or feather-edge cladding and more resilient than OSB. Leave a few mm expansion gap between boards and seal with silicone. For about £150 it would give you a weather and bug proof structure in one day, At a later date you could install any cladding on top of the ply (make sure to mark the stud locations). It won't matter what warps or shrinkage you get in the cladding you choose as the box will already be sealed.

Outdoor and obsy cabling considerations: Pipes can really attract slugs, had a motor control unit burnt out by a slug that thought a buried electrical conduit a good route to somewhere nice and warm. It started a fire on the pcb where the mains transformer was mounted. Now all conduit/cabling pipes are sealed with silicone.

The NLC's do look amazing tonight!

A picture or 2 would be great, I'll start a thread on adjustable piers.

Sounds impressive, does it keep PA from night to night? Sorry to James for the thread hijack!

I've been looking at actuators, is there a thread on how you did this? Interested in what you used mechanically to get a precision lift, was it a telescopic pier?

Good luck with your build Alex, I've done loads of projects lately and found some local suppliers that really help keep costs down. Check out some of the cheapest pressure treated framing timber in the country and not too far away so cheap delivery. http://www.diyclick2buy.com/ Another local supplier (good for ply, treated framing and decking) with a great reputation: https://www.savoytimber.com/ For shiplap/loglap these seem the best value: http://www.ebaystores.co.uk/qualitytimberproducts Curious about the roof tech you intend to use, any more info?

Be careful when adding or laminating more lateral thickness to your end supported beams, this will add more weight and not a lot more resistance to long term flex. Thinner taller beams if they can't move laterally will be stronger and lighter, laminating thinner beams with carbon will save weight and increase rigidity.

If you are height restricted (2.5m) you may not be able to increase your yellow beam size to 150x22. You might see some distortion of the yellow beams over time. You could consider using some carbon tape and resin between the yellow beams and also do a little pre-stressing while the resin sets. It would be even better to use 4 x 100x22 with carbon laminated between each beam. This would probably do the job: Carbon tape. You would also need some laminating resin .