Astwood Observatory - belated update.... c)

[Robd]

First Turret frame and two turrets near completion

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Installing first turret

On the move.

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Going up.

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Steady does it.

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The turret was the carefully slid into position and lowered. Not easy it was da....d heavy and had a mind of it's own.

To be continued.

Rob

[George]

I already have an observatory, but seeing that wants me to tear it all down and do it again

Keep the posts coming its looking very good.

[barkis]

Sure is looking Good Rob. It is a very professional build, and I look forward to the opening ceremony. You must be very pleased it's nearly done.

Ron.

[Jeff RV]

Looks very well made Rob, Fantastic stuff!

Jeff.

[centroid]

Hey, that turret looks remarkably familiar, its even got the same number of sides.

Its really looking 'the business' Rob.

Dave

[Robd]

No surprise there Dave, I seem to recall that we banded around a few thoughts about the turret shape and rings at the beginning of the year.

I managed to get out a couple of nights ago and start aligning the SW rig. Miles off but had plenty of adjustment. I am having a lot of trouble getting my head round the relationship between the modified webcam view, ascom's NSEW and the which way to rotate the mount - too many three dimensional views for my old grey cells. The process was not helped by the target star galloping across the field of view on the webcam. I have also lost sight of Polaris behind a tree due to the mount being moved 1m to the east, making initial set up pure guess work.

Still perseverance will get me there eventually.

Rob

[centroid]

Still perseverance will get me there eventually.

Absolutely Rob, remember old 'Robert the Bruce', and the spider.

BTW, looks like you've also used the Thompsons High Performance Roof Sealer, on the top.

We've had a really wet period since I finished my obs conversion, and up to now, the Thompson's seems to be very effective and durable. Winter is coming up of course, but I feel very confident with it.

Dave

[barkis]

Does this Thompson High Performance Roof Sealer get painted on, just as if you were painting the surface. Then does it turn into a rubberised membrane when dry. ?

Cheers.

Ron.

[Robd]

Dave,

yes it is the Thompsons roof sealer. I used it following your own experience with it. I had originally thought of felt but the turrets are heavy enough already so seeing your comments I went for it. The only problem that I have had was of my own making. The turrets at 2m dia. are to big to get out of 1 board so I had to use two with a 2" x 2" joist under the join running from the back of the shutter aperture. Unfortunately I did not put enough screws in and it leaked. Similarly with the shutters I could only get 1 out of an 8' x 4' panel so used the offcuts from the turret roofs with 2" x 1" reinforcements over the joins. These also leaked, so I had to get another 2 sheets and re do the shutters.

Since then there has been no sign of any more ingress, despite all of the rain that we've had.

In hind sight I should have put a little more angle on each turret roof, I only aloud 1" on each, should have gone for 4" as I think you did. 1" does not allow enough for 'build errors' resulting in a small puddle.

Ron.

In principle yes just paint it on. However it has the consistency of slightly thin treacle. It can be applied with brush, roller or broom at 1/2l per sq m (if I remember correctly ), which seems a lot, especially to me since I have a tendency to under apply paint. I therefore have had to apply three coats where two should have been enough.

I found out the hard way that it will not stick to mastic sealer. As a belt and braces job I applied the mastic to the edges of the roof panels where thy contacted the frame. The THPRS would not stick to it so I had to sand all the mastic off and start again.

And yes you end up with a rubberised membrane.

The other comment on it is do not apply on a nice hot sunny day - it drys to quickly in the sun and picks up very easily making it difficult to get a decent finish when doing a large area.

Rob

[centroid]

My turret is 1.8m wide Rob, and the roof panel has two joins in it, but these are underneath the 25mm x 25mm aluminium angle track, onto which the hatch runs off. These joins were sealed with Polyfilla felixible exterior sealant, as were the seats of the countersunk screws, that fix the track to the roof.

The roof comprises three separate 6mm ext ply panels. Two full length ones, running fore and aft, on either side of the slot which are 600mm wide, and overhang the turret sides by about 30mm. The third panel, fits in the gap betwen the outside panels, and the back end of the slot, with the joins covered by the ally track.

The roof has a 5 degree slope on it, running towards the rear, and sheds the rain nicely. Not had any leaks or puddles at all.

The ply panels came as 2400m x 600mm.

It al probably better explained by the pictures on my website.

Dave

[saturn5]

Superb work guys.a lot of very envious ppl looking on.