Obsy help and plans

[Gina]

Brilliant! So simple.

[Gina]

Dug some more out of my hole. Quite wet clay now plus plenty of stones - quite hard going but not too far to go to the 2ft depth.

I've taken the plunge and ordered the NEQ6 Pro mount. After checking my bank balance I went for the full SynScan GoTo model. That way I can get going straight away and sort out computer control later.

[malc-c]

Gina, nice to hear your bank balance has taken such a hit

On the subject of brick built obs, I'm raising the floor of my intended build, something like this

Brick built observatories are around

Piazzi Smyth Observatory in Bedford is one example

[Gina]

Your obs looks good Malcolm - nice diagram. Should be a nice place. Good luck with it

[swag72]

Great news Gina!! Thats it, brick seems fine!!! I'm having a plan now!!

Just one pier question - Can it be as high as I like?

[malc-c]

Uhmm.. been out with the tape measure and I think I've come up with a flaw in my plan to raise the floor.. this would mean the headroom would be a max 5' so even my small stature would have to stoop whilst opening and closing the roof.

Looks like I'll have to go with the option of 6' walls with a higher pillar and use a set of steps if I need to visual anything that is above my eye level.

[Bizibilder]

I strongly suspect that the brick built version is for building security rather than anything else - it seems to be "public", it has disabled entrance ramp and a VERY thick steel door!!

As to pier height - any height you want if you make your own. Usefully you can set the scope up in such a position that it can be shielded from local lights - you may lose a bit of horizon but that is a small price to pay.

[swag72]

Excellent - I am going to get my pier fabricated out here, so I guess I'll be able to go any height. What width does the pier stand have to be? It will be holding a SW 120ED + camera etc at the moment. Who knows in the future!!!

[Bizibilder]

Around 300-450mm should do. It'll be firmly bolted to a planet so it shouldn't move much!

[swag72]

Sorry, didn't mean the stand - Meant the diameter of the tube!!!

[Bizibilder]

The larger diameter the better, wall thickness is a secondary consideration. I would suggest somewhere around 5" -8" - but beware prices rocket up for the larger sizes! My own is 5.5" (140mm OD) with four 50x10 braces welded up the sides of the tube (like a cross in section).

[Digz]

This is an interesting read.

I can see the issue with using blocks in a warm climate - all day will be spent soaking the heat into the blocks only for it to radiate back out at night!

To avoid this problem you need to disengage the block from the atmosphere. You could insulate externally, which sounds kind of perverse but the insulation will keep the blocks cool. The only issue with this is additional cost and making sure the insulation is made waterproof for any wet downpours.

Its really interesting, as an Architect, I like to employ thermal mass (i.e. blockwork, concrete etc) because I can use it to cool buildings down at night and keep buildings cool. However the Architecture of observatory design is completely different.

You might be as well to build it out of timber as this is thermally light therefore any heat gathered during the day will be lost quickly as the temperature drops. A secure obsy can be built with a suitable timber frame.

Anyway, just my 2p worth

[swag72]

Great comments - Thanks. So if I go down the brick build I will need to insulate the outside. Does sound odd doesn't it?!

[Digz]

That would be my advice on a brick built obs in such a climate as yours. I don't know the exact numbers but I would imagine a brick structure which has been soaking up the sun all day would radiate that heat back out for several hours after sunset. Insulating or disengaging the brick from the heat source in the first place will help to stop it, in my opinion.

[swag72]

My other reasoning on a brick build is as follows.

Where I am looking at putting it - In fact anywhere it could go - Is covered in concrete slabs, with 8m3 of concrete underneath them (That's one whole cement lorry to you and me!!). I've got concrete and brick build out houses around me, a concrete pool - So all in all, I decided that with all that radiating heat, a few more bricks probably really wouldn't make any difference!

This is the first full year that I have used the scope so far, so I have no experience of what to expect with all those heat thermals in my spanish sun. Perhaps it will be so bad that I can't do anything in the hot months anywhere on my plot - I really don't know.

[Digz]

Ah ok that's good and it does help. Another thing to consider is the area of existing concrete that you will effectively be covering up with your obsy as this will offset, to a degree, any additional bricks added by the obsy. There is also no harm in building it from brick and seeing how it goes, you can always overclad with insulation later if you need to.

[Bizibilder]

On reflecting on your last post any form of insulation would be pointless - you are surrounded by so much concrete, brick and whatever that adding an observatory will have no effect at all on the radiated heat that you will have to contend with.

You main friend may well be the clear sky - allowing quick radiation of all that heat early in the night so you should be OK once it is fully dark.

I wonder if you are worrying over nothing?

[swag72]

I'm thinking about how to roof it at the moment. If I have solida walls and an aluminium door into it, then I will want some type of dome type roof structure as I will have the pier quite high to get over the walls - I'm wondering about some kind of big square agricultural type container for part of the roof.

If this comes off, it's going to be VERY Heath Robinson!!

I do hope I'm worrying over nothing!!

[Bizibilder]

Heath-Robinson are the Rolls-Royce of Observatories!!

[Digz]

On reflecting on your last post any form of insulation would be pointless - you are surrounded by so much concrete, brick and whatever that adding an observatory will have no effect at all on the radiated heat that you will have to contend with.

You main friend may well be the clear sky - allowing quick radiation of all that heat early in the night so you should be OK once it is fully dark.

I wonder if you are worrying over nothing?

I reckon, in this instanace, you are right. There is so much concrete and block around the addition of the obs shouldnt make any noticeable difference.

[Gina]

I agree.

[swag72]

Chief engineer (my Dad) is up to measure tomorrow!!

[swag72]

OK, plans in my head, will see how they go later on today - However I do have a couple of questions that I need to sort out in my head first.

1) Is it OK to have the scope and mount in the horizontal position (balanced) when not in use? That will minimise my height and help with roof ideas.

2) Do I need to offset the pier in the obsy? If so in what direction and why?

3) I have read about getting the pier / adaptor really well aligned prior to fixing - Why? What I don't get with this is that the adaptor and seating for the mount is circular, so you can surely put the adaptor plate and pier a direction roughly facing north and then make it exact when seating the mount. The mount will afterall move around 360 degrees.

That's it for now - More questions will be incoming!!!!

[Gina]

1) These mounts have a "Park" position (well my EQ6 does and I think the 5 is the same). The mount is upright, scope on top, scope horizontal. Not as low as you would like but at least the scope isn't vertical.

2) I don't really know - some people do. I'll let others answer that.

3) There is limited movement on the azimuth adjustment on the mount. Can't remember ATM just how much. The mount has a gap with two handwheel screws which press on the peg to adjust azimuth for polar alignment. As I recall the adjustment is something like plus or minus half an inch at something like 2" radius. I calculate that as +- 15 degrees. So if you get the pier adapter aligned with the peg north within 10 degrees say you should be alright.

[swag72]

Does the mount HAVE to be left in the park position? I ask as this will give me extra height issues if so.