Gina

That would be too far from the observatory and windage on the rig would put a lot of strain on the mounting plate and hence the woodwork of the observatory, I think. Thanks for the suggestion though.

A while back I was thinking of a combined ASC and wind instruments. That still has certain appeal. It means the weather station doesn't obstruct the ASC view. Now I have a 3D printer with a 400mm x 400mm printing area that works well, I can make bigger prints than before.

I previously had an aluminium pipe attached to the ROR running rail on the south side with the ASC being just above the ROR apex. Better would be to mount the mast on the north side of the warm room spaced out from the wall by about 3" to make room for the ROR. I guess if I used a fairly large pipe I could feed dry air into it from the warm room. Hmm... needs more thought. I agree that having fixed cabling is best even though it's only power feed. Earlier ASC versions tried using the aluminium pipe to conduct heat away but it wasn't adequate and the hot side of the Peltier TEC got quite hot. Actually, I already have a bracket for a 1¾" ali pipe in the middle of the north side which I had planned to use for the wind instruments of a weather station.

This photo shows why this isn't practical unless the ASC is on a long pole (mast) mounted clear of the ROR. That was what I did with earlier versions but had problems.

The south side of the roof doesn't have this bar as the construction is different being a solid wall. So the hole for an air duct could be immediately below the barge board. OTOH I still don't feel like working on the south side in view of the access problem and safety issues. Also, it would need a hole in the shiplap cladding and I'm not sure how I could seal that.

Here are new photos of the north side window from outside and inside. This shows that a hole for an air duct (or the ASC casing) would have to go below that cross member just inside the window.

ZWO ASI 120MC-S has arrived. It's a bit smaller than the 185MC so I shall need a new housing. Not a problem have CAD software and 3D printer.

That looks ideal for planetary imaging. Following with great interest...

Depending on the weather, I should be able to go out to the observatory tomorrow and check things out. I think the main roof opening and closing was pretty much sorted out though the big pulley may need to go back further towards the warm room as I recall. I have an H-bridge motor driver Arduino shield that Per recommended 4 years ago that I can use to control the roof motor unit, though I expect to control everything with an RPi under INDI and KStars/Ekos (there's an INDI driver for controlling roll off roofs). If I use the roof to operate the drop-down window, it will have to be on the south side as the north side of the roof is too high. This will mean moving the downpipe from the guttering on the ROR as it will be in the way. One option would be to have the downpipe on the north side - not a problem, I don't think.

Yes, linear actuators would be good I think but on looking at prices are probably not the cheapest option.

I think the answer to the east window problem is to counterbalance it and use the Olly type system. Not particularly neat but nor is anything on my property! It will need stiffening up but I think I can do that. As for the storm protection, the roof already engages with holes and eyes when closed, on the south side and I should be able to arrange the same on the north side. Then it would be just a matted of remote controlled bolts or latches to stop the roof opening. That shouldn't be too difficult - they could be motor driven like the main roof but on a smaller scale. Windscreen wiper motors could be arranged to serve the purpose, I reckon.

With probably the best chance of clear skies and good seeing being in the middle of winter on a freezing cold night, the thought of being able to open the observatory roof and start up an imaging rig remotely while sitting in my lovely warm living room certainly has some appeal!

Well, I said it wasn't really possible to unlock the storm lock-down systems remotely but to quote a saying we had at work umpteen decades ago, "The difficult we do straight away, the impossible takes a little longer!" and I have gone by that paradigm ever since. With 60 years of engineering experience I reckon there's a good chance of coming up with something ?

Well, I think it probably is! ? I'm certainly giving it thought...

Camera held by two brackets (avoiding printed bridges). The focus motor bracket will be attached to the lens rather than the camera bracket or dovetail and the electronics box will be attached to the dovetail separately.

Yes, I have. I may be able to do something like that.

I have several PC processor coolers of various sizes and I'm thinking a small air blown cooler is going to be more efficient than my 90mm x 90mm x 60mm passive cooler, particularly as the passive cooler is not in it's most efficient orientation. Once I get the ZWO camera I think I shall set up some comparison tests. I have a 60mm fan cooler and 50mm flexible air duct and one option might be to put the cooler in the ASC and feed relatively dry air from the scope room through the flexible 50mm ducting. I also have 100mm air ducting but that is fragile and intended for indoor use and I doubt it would stand up to storms outdoors. The north side of the ROR has acrylic sheet for a window and it wouldn't be difficult to cut a hole in it - I have various size hole saws - so it occurs to me that I could cut a round hole near the apex. With my large 3D printers I could print a pretty large housing that could actually go into the scope room. Of course, there is still the problem of sealing the astro camera from the heatsink air side. This is a rather old photo of the north side of the observatory and shows nice pristine window panes. ATM they are broken at the bottom and covered in mould or something and I expect to be replacing them with new acrylic sheet sometime soon. So I can cut the hole before fitting the new pane.

Since I seem to be getting back into imaging I think there's a very good chance of resurrecting this project. The main outstanding problem is the fold down window flap but if rain arrives it's usually from the SW and the window faces east so wouldn't matter if it were left open. The storm latches and bolts can't really be automated so there would be a manual "pre-opening" anyway.

Just been out to the observatory to re-examine ASC position options. The ROR apex still looks best but I think I'll put it on the north side instead of the south as I can get at this more easily. The south side is close to the boundary and awkward to get steps in. Also, I can see all of it and not just the top from the living room window. The power cable run is much the same except to the north of the pier rather than the south. It connects at the pier-head to the main 13.8v observatory supply. I might change the cooling arrangement for the Peltier TEC that cools the camera. Rather than a passive, convection cooled heatsink outside, I could use a copper strip to go inside the roof to a proper fan cooled heatsink (I have several designed for PC processors). The passive cooler is rather dependent on wind conditions - with a good wind blowing through it's very efficient otherwise, less so. The other thought I had was to cut a hole in the side of the roof and put in a fan blowing air out of the scope room over the fins of the passive cooler but I doubt this would be practical. Of course, if there was an outdoor type 12v fan I could use that but I don't think ordinary PC case fans would survive. Unless anyone knows different...

My earlier ASC versions had the electronics inside the same casing as the camera and lens. That meant just the power cable going into the enclosure but I wasn't happy to have the RPi plus other electronics inside an unventilated and maybe heated enclosure.

I now need to redesign the casing to make it totally waterproof - I don't want the next storm to destroy another camera. As I see it, the main problem with waterproofing is cables. I have grommets for round cables but ATM the motor cable is the flat type and the dew heater and camera cooling wires are single wires. The other cable is the USB camera feed. That is round but has connectors on both ends. One answer might be to combine all the wires in one or maybe two large(ish) round multi-core cables or maybe I could "cheat" and seal the cables/wires with the ubiquitous hot-melt glue.

ZWO ASI 120MC-S ordered and on it's way.

Why the multiturn precision pot? Do you really need that resolution?

You are right! It did but worse was that the print parted from the bed after a couple more layers. However, it holds the camera very firmly without the top/back part. The arch at the top of the camera is very stiff. I may print it again but without the back ring. I'll sort that out tomorrow.

I have my (fitted) bench under the window where it will get best light in daytime.