Gina

Print finished. Here are a couple of photos with the top camera casing, camera, lens and focus motor added. Rather a rough print at high speed just as a prototype - not the finished version.

Thought I'd do a Google search for aluminium boxes with the thought that a Peltier TEC in the bottom could warm the dome and found another possibility :- ALUMINIUM SQUARE BOX SECTION 11 Sizes 10 Lengths with one option as 4" square and 100mm high. That's 4" outside and 3mm thickness. This makes the inside 95.6mm square. Now the passive cooler is 95.0mm square so the top of it would fit nicely inside the box section. It would need clamping on and sealing to keep damp out but it's an interesting idea, I think.

The Peltier TEC eventually came off the passive cooler so I can change the cooling if I want to. OTOH passive cooling does have its advantages.

It's just occurred to me that I was going to use some of the heat from the hot side of the Peltier TEC to warm the underside of the dome to help with dew heating and stop dew on the outside, but now I don't see how I can. It just seems daft to have heat to get rid of and heat wanted under the dome yet "ne'er the twain shall meet". I may get thinking again and see if there is any way of using the spare heat.

Next try at the model for the bottom casing.

Not right yet but going in the right direction... Needs more room for the focus motor.

When I last looked there was just one left on Amazon.

Here's a screenshot of the first CAD model. I think I'll print one and see how it goes. There are other bits to add such as clamping for the camera casing top and attachments for the top part of the outside casing.

I think combining the two is on. There would be a 5mm gap between the housing and the cooler which could be filled with rubber foam for sealing. The disadvantage would be that this seal would by the only thing separating the camera from the atmosphere unless I use sealant around the Peltier TEC and its leads.

I'm just wondering if the bottom of the camera casing and the bottom of the outer casing want printing in one piece. OTOH I doubt this would be possible without support material.

Gap between camera casing and and passive cooler is just 4mm. From cooler to top of camera housing is 44mm.

I think the outer casing is going to have to be in two parts bolted together.

This is the south side in the scope room. I'm planning to use the east end (left in the photo) base upright to take the hinge band for the roof lock that prevents roof lift off when closed, with the hinge pin part on the ROR bottom frame member. The solenoid latch and lever that holds the roof closed could go on the second from left upright with a pin or plate screwed to the roof lower frame member. I plan to keep the over-centre latch in the middle as the ultimate storm protection to be applied when a storm is forecast or if I don't plan any imaging.

The roof latch solenoid has arrived so here's a photo together with a steel rule to show size, which may be a tad small. I think I shall implement my lever idea as shown below to give more holding the roof closed. The lever design will need to be such that there is minimal amount of possible roof movement when roof closed and latched.

The camera clamping could be part of the outer casing. This would mean the outer casing could be attached to the passive cooler with the four threaded holes in the cooler and M3 screws. Rubber foam could be used as the seal between casing and cooler.

Still to do :- Pair of gears for focussing. Simple. Clamping camera to Peltier TEC. Not so simple. Outer case design with weather seal. Difficult. Fixing to observatory. Relatively simple I think.

The observatory jobs are on hold today - weather not good enough for roof repairs and waiting for parts for the roof automation - so this project may get some attention today, if I can get my brain to engage! ?

I remember those slo-mo drives for decades back when I was playing with radios, for tuning drives.

Here's a screenshot of the FITS image - out of focus! 30s and gain at 50. Camera temperature 1.2°C no cooling. Too tired tonight to do much but may do more to it tomorrow though whilst the weather is good I want to do the observatory.

This needs work before I can do any more testing. The focus I set up manually needs setting up again and it's very critical - a few degrees rotation makes a difference, so I need the motor focuser working. I also need to arrange to clamp the camera onto the Peltier TEC. Then there's the outer casing and dome to sort out, with the problem of sealing. I've been concentrating on my observatory today.

Ordered a pair so will just have to wait and see if they work.

These look suitable for the east end :- 10" GATE CRANKED HOOK & BAND HINGES HEAVY DUTY STABLE GARAGE SHED BARN DOOR D30 The amount the hook part sticks out would seem to be alright. There are other hinges available but no dimensions given.

Been out to town to try and get hardware for holding the roof down. Only a modicum of success! The shop I usually go to has closed down and replaced by a furniture store. Another I've used in the past now only does pet stuff. Got a recommendation for another agricultural shop but they had a very small range and most of it was far too big. I did get one bit and another that I might be able to use though I think it's too small. Also tried ScrewFix and Homebase. Did pick up guttering parts at Homebase for the roof repair.

Oh yes - I like a challenge too - as you know.

Been out to the observatory again this morning checking up on things but just thought of another possible problem so I'll be out again shortly to check. When the roof is closed you forget what happens when the roof is opened and that attachments to the ROR have to go through the gap between ROR and middle wall.