Planning My Observatory - Feedback Wanted!

The is a good idea on your last point.

Alternatively, you can use a good compass and correct for magnetic diurnal motion for 2005. In addition their is an advantage of using the very finest threaded long bolts for fine tuning azimuth. Of course you probably have fine tuning facility within the mounting. Its comforting to have +/- 5 degree from N -S line for flexibility.

Eamonn A

The is a good idea on your last point.

Alternatively, you can use a good compass and correct for magnetic diurnal motion for 2005. In addition their is an advantage of using the very finest threaded long bolts for fine tuning azimuth. Of course you probably have fine tuning facility within the mounting. Its comforting to have +/- 5 degree from N -S line for flexibility.

Eamonn A

The wedge I have came with a compass but I can't trust it completely. Looks great and shows all sorts of markings for magnetic diurnal motion etc. However, when I rotate it back and forth, the needle also turns a bit and doesn't always come back to the original position, strangely enough.

Does the wedge have a built-in bubble level. If it does, dont blindly trust it.
Mine was off, I now use a 6 inch mini level.
Also, the liquid in my bubble level actually evaporated even though it was "sealed" , :lol:
I had debated in my mind when doing my pier whether to use 3 or 4 thread bars for the top plate, 3 would be easier to level, but I went with 4 for the increased stability.
This might not be such a big factor for you as your scope + wedge is much lighter, 3 might do it for you???

I got my steel pillar today. It's made of a 200mm box section of steel 750mm high with 350mm x 350mm x 12mm thick steel plates top and bottom. This thing is *seriously* heavy. Was a real struggle to lift it in and out of the car. Now I am trying to drill the holes - really slow work. Anyway, here's a pic:

Must've been heavy - you can see the finger marks where you were holding on for dear life :lol:

Looks like a well solid pier Michael. You won't have any issues with that moving around at all

Just out of interest, how long did it take for the concrete to set?

Cheers

Dave

Concrete gains about 70-80% of it's strength in 24hours. At this stage however, I haven't drilled any holes in it, just positioned the pillar in the shed. The concrete is more than strong enough to walk on etc after 24hours.