I'll try a close-up as you suggest.

I can't see any way to repair the image board myself.  Whether ZWO would be interested in repairing it I don't know but I have an uneasy feeling about the cost if they do.  Also, I have no idea if the wet has caused damage elsewhere but suspect it probably has.  I guess one option would be to see if they could repair the camera as a whole.  ATM it all seems too much trouble! 

I have a mono camera (ASI178MM) I could use, with much the same sensor size but this was a similar price and not sure about risking it in an ASC plus I would prefer colour. This camera has a much higher resolution than the dud one - higher than needed really.

I shall continue to give this thought.

Looking at camera specs, I don't think the ASI178MM is suitable for this application.  Of the range of ZWO cameras sold by FLO, only two seem to make any sense.

1. ZWO ASI 120MC-S USB 3.0 Colour Camera - £154  which wouldn't cover the whole sky.
2. ZWO ASI 385MC USB 3.0 Colour Camera - £348  The replacement model for the camera that got destroyed and twice as sensitive.  This would be the ideal night sky camera.

ZWO ASI 185MC or 385MC have a coverage of 7.26mm x 4.11mm.  ASI 120MC has a coverage of 4.8mm x 3.6mm.  That is 87.6% of the height of the 185/385.  This is not as bad as the diagonal sizes would indicate as the 120 has a narrower X to Y ratio.  Here are a couple of screenshots of the two image sizes.  First is the image from the ASI 185MC and the second the same image cropped to the size of the ASI 120 image sensor with the original size (185 camera) shown as a dashed box.  The loss of coverage is far less that I anticipated and seems acceptable

I have decided to get the ZWO ASI 120MC-S from FLO.  I feel a bit "lost" without the ASC image to look at!  If this camera turns out not right for my ASC I can use it for planetary imaging later as I have in mind.  My standard widefield imaging rig is taking priority though.

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

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.

1 minute ago, Gina said:

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.

I'd suggest exterior grade silicone sealant rather than hot-melt I think.

James

I haven't used my casing yet... but I just printed a two-part base and glued the halves together. A USB cable goes in through a hole sealed with hot melt, there's a pocket for silica gel pouch(es) and I made a foam gasket for the dome. Hopefully sealed!

Must try it out some time, but I only have the one suitable camera.

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.

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...

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.

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.

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.

I was looking at the older photo Gina, wondering if it might be less work to mount it on the western end of the warm room, so you wouldn't be cabling up to something that needed to move?

James

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.

9 minutes ago, JamesF said:

I was looking at the older photo Gina, wondering if it might be less work to mount it on the western end of the warm room, so you wouldn't be cabling up to something that needed to move?

James

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.

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.

46 minutes ago, Gina said:

Not a problem have CAD software and 3D printer.

You don't say! ?

You could possibly use a satellite/FM aerial mount such as this to avoid the roof?

https://www.ebay.co.uk/itm/Satellite-Dish-Wall-Mount-Bracket-Terrestrial-Aerial-TV-Mast-LNB-Universal-UK/301286434985

James

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.

5 minutes ago, JamesF said:

You could possibly use a satellite/FM aerial mount such as this to avoid the roof?

https://www.ebay.co.uk/itm/Satellite-Dish-Wall-Mount-Bracket-Terrestrial-Aerial-TV-Mast-LNB-Universal-UK/301286434985 

James

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.

I'm going out to scour my property for pipes ?.

7 minutes ago, Gina said:

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.

Perhaps an ultrasonic wind speed/direction detector might be useful in that instance.  I imagine a rotating cup design might induce a fair bit of vibration.

James

2 minutes ago, Gina said:

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.

Yes, making sure it's adequately mounted on the wall would be the important bit.  If that's not possible then clearly it's a non-starter.  If it's designed to carry a satellite dish though, I imagine an ASC shouldn't present a big problem in terms of the wind.

James