Gina

Looking again at the dome cover linkages and control.  There wasn't room for the axles in/on the lid so moved them down.  The first 3 screenshots show the operation.  The 4th shows what can happen if the axles aren't coupled.  The cover just clears the dome and with 180° rotation of the axles, nicely clears the FoV.  Next problem is driving the axles.  They need coupling so that they revolve together.  I've thought of 3 possibilities.

1. Timing belt and pulleys
2. Spur gears with pinion in between.
3. Linkage.

One needs turning from a motor, of course, and that can be the one that runs through the box, so can be driven from inside.

Cloudy here.

Yes, I noticed that!

As Title.  Repeat of Monday's programme about life on Venus.

To answer you question.... no.

It's much easier to use a template for drilling holes than ultra careful marking out and very careful drilling.  Designing and printing a template is much easier and almost guarantees getting the holes in the right places.

I've designed and now printing a template for drilling the holes in the box top - 12 of them.  The circular part fits in the hole in the lid and the two straight bits fit the edges.

I can team this up with an 8 hole dome clamping ring with the ring rotated 22.5° so as not to clash with the arms of the camera casing.

Decided to fasten the camera housing outside the dome clamp ring so the two are independent.  This is the new camera casing.  The previous one inherited so much unwanted code from previous versions that I decided to start again.  The result is a tidier looking model with strength just where needed combined with thermal insulation.

With a steadier wind direction today I have been able to correct the North offset by 2 more points.  We have had light and variable winds since getting the wind sensors working properly and it needs a nice steady breeze to set the North Offset more accurately.

The design still isn't settled!  I realised that I shall want to take the dome off (or not put it on) while having all the rest assembled so that I can rough focus the lens with the motor focussing half way.  The lens focus ring is not so tight in the focus lever ring that it can't be turned by hand.  The current design has the camera housing attached to the box top by the same bolts that hold the dome clamping ring.

Yep, we always like lots of photos 😀  Good luck with the restoration - sound like a fascinating project.

I've measured the bottom of the box and that is as advertised.  Fitted the dome on temporarily with the new dome ring and camera casing, with M3 bolts and nuts.

I need to make some small alterations to my designs as the box isn't as big as advertised.  It's 190mm x 140mm outside not inside.  With walls 3mm thick the inside is 184mm x 134mm.  That's the lid  - I haven't measured the bottom part.

The dome clamp ring is 150mm diameter and that was supposed to be the width of the box outside.  Now I shall have to adjust it.

Underside view of new dome clamp ring with groove for flange.

I'm using 200mm f4 lenses for AP but these are vintage SLR lenses and bought second hand from a well known auction site for very little.  I use them at full aperture on 4/3" sensor cameras.  They are sharp well up into the corners as are all the Asahi(Pentax) Super Takumar or SMC Takumar lenses I use.  One difference from that $700 jobby is that terrestrial lenses are not fully APO right into the deep red but with narrowband this doesn't matter - just that the focus at OIII wavelength is a bit different from Ha or SII.

Cut the hole where the dome goes with a trepanning tool (aka tank cutter) by hand.  Too big for electric drill.  Good exercise 🤣

It will need both shafts driving though, otherwise you can get this.

I think I have it.  I've only modelled the linkages on one side - they will be on both sides in the final construction.

That was just one of a number of problems!! Although the cover is a lot bigger than the dome, it has to lift higher to clear.  I'll continue experimenting...

I'll look at right-angle or curved linkages - good idea.

Thought I'd look at a double linkage for a dome cover (thought if it isn't inverted it won't catch the rain) but it won't work.  I've tried various lengths of linkages and various positions for the pivots/axles but the parts always interfere before the cover clears the FoV.  Guess there are other variation (an infinite number) with different linkage lengths.  This could take a lifetime without previous knowledge of all sorts of linkages, which I haven't got!!

I've been trying the parts in the box and there's not as much room as expected.  I was planning to put the dome towards one end of the box giving maximum length of focus lever but now it looks like the RPi and HAT will need to go at the opposite end from the focus stepper motor as there isn't room for both motor and RPi in one end.  The focus lever may still be longer than with the 3D printed casing though.  I still think I can get everything in but there won't be much empty space!

Sorted out how to produce an extension to the bottom of the box to contain the waterblock connections.  This will be sealed to the flat part of the bottom with an O ring and fastened with either bolts and nuts or self-tapping screws.  A smear of silicone grease should seal any tiny surface irregularities.

I'm now printing some of the parts to see how they fit in the box, starting with the biggest.  This is the camera housing both holding it and providing thermal insulation.  It is attached to the box lid by the legs using 4 of the dome fixing bolts.

The box has arrived and I'm not very impressed!!  The top is alright but the bottom will make it difficult to seal the extension to it.  It isn't waterproof as the lid fixing screws are inside the rubber seal.  I hadn't noticed that.

I think my preference is for the waterblock with downward pointing pipes.  This is a model of an extension I could clamp to the bottom of the box with an O ring for sealing.  The pipe connection in the middle is for the air pipe (to apply slight positive pressure) and the water pipes are a tight fit in the two holes.

With round cone attachment to mast.

Possible mounting methods.