Gina

Ah yes, that's the other one I was looking at.  It's a lot bigger than needed (and wanted).

I have another idea.  I have another waterblock which is 40mm x 40mm x 10mm with side connections/pipes.  This is easily enclosed within the box and the water pipes could come out in a different part of the box.

That link isn't working for me.

Here is is with both parts of the box - shown in Blue (clear).  This shows the pipe connections on the waterblock poking through the bottom.  However, I believe I have an answer to this.  Add an extension to the case with a sealing O ring in the same way as the dome is sealed to the top.  Then, the water hoses can go through holes slightly smaller to provide a seal.

Waterblock modelled and added to assembly.

Been designing parts for the ASC using that PVC box.  With this case I can have a longer focus lever giving finer control.  As with the other design I can still use the little 28BYJ-48 gearbox stepper motor with cam.  This can be mounted inside the box from the lid top.  Here are some screenshots of the assembly.  The Peltier TEC fits in the cavity against the red casing of the camera and the waterblock onto that being secured by screws into the 4 holes around the camera casing.  The model of the box is approximate since I don't have complete details.

Been looking at how I could use the box and reckon I can solve all the problems - probably.   It should be better in a couple of ways.  I have ordered one.  I can't be sure everything will work until I get it.  Should arrive tomorrow.

I've been looking again at plastic boxes for the ASC casing but not found anything really suitable.  This one is the nearest I've found.  It has a big enough flat area on the top for attaching the dome with sealing O ring but the bottom makes for less easy attachment of the ASC to the mast pipe while keeping things sealed.  It's also a little on the shallow side and the waterblock connections would protrude below the bottom.  I'm thinking about it - it could shorten the time to get the ASC up and running again if I can get round the limitations.

With the dome cover being very tricky to design and taking a long time I'm thinking of leaving that for now and producing an ASC without it so that I can get an ASC working to allow me to see the sky conditions for imaging.  Coming up to new moon I could do with it.

Thank you for your post, I'm always grateful for suggestions and opinions.

I have tried so-called waterproof enclosures for the ASC casing but found them worse than 3D printed casings.  I have produced 3D prints which hold water fine but I do appreciate that there's a difference between holding water and being totally vapour-proof.  I don't think any plastic is entirely vapour-proof.

I have come to the conclusion that a totally vapour-proof casing is so near impossible that another approach is needed.  This is to apply a slight positive air pressure inside with dried air.  I would hope that any permeability or leakage would be small and that the airflow through some silica gel desiccant sachets would be minimal so that I won't need to change them very often.  I'm thinking of a small radial fan for providing the air pressure.

Been searching for brass worms and worm gears without much success other than on a slow boat from China and not quite what I want anyway.  OK I can 3D print a pair but this is not ideal - I would prefer metal (other than ordinary steel).

It would seem that there's plenty of room for the RPi 3 plus HAT to sit flat inside the casing and I reckon I may be able to halve the space required which would result in this.

I'm doing a test print to see how all the electronics fits in and it's looking like I shall be able to reduce the height considerably.

Offset bracket and drive wheel (probably a 3D printed spur gear).  It's very close to shedding rainwater in the open position and I may be able to make the main casing shorter depending on how well the electrons fits in.

Think I'm nearly there- watch this space.

I'm not sure what you mean by a 2 lever arrangement but one thing is sure - what I have won't do - there's nowhere to put a drive gear or pulley that wouldn't be in the FoV!!

Tried your suggestion of cranking the cover to axle part which does help with the angle but too much intrudes on the FoV!

I've changed the cover design to ease the rainwater problem.

There's another thing to add to the list - must be capable of being 3D printed (without support).

And closed also showing the axle.  That mounting axle is all of 100mm (4") out from the edge of the cover.

This solves the rainwater problem but...

This shows the sort of problem.

My first thought was to feed a shaft through a gland for sealing - this does seem the simplest solution.  I have a box of small O rings.

At first it seems simple enough to make a remote controlled cover but when you look into all the details, it isn't.

1. The cover must not obscure any part of the all-sky view so all of it must be below the top of the lens
2. It must not collect rainwater.  Even though it will only be opened in good weather, rain can come suddenly.
3. The drive mechanism must not be subject to corrosion
4. It must be robust enough to withstand storms

The biggest problem is driving the cover without risking wet getting inside the ASC casing yet have the motor protected from damp.  Either that or some method of opening and closing the cover that will stand getting wet or at least damp.

This is where the SGL membership with the vast range of experience might help.  Any ideas very welcome, please.

Started designing the cover.