Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Planning an observatory. Is placement critical?

  • Please log in to reply
8 replies to this topic

#1 Oscar Szentirmai

Oscar Szentirmai

    Messenger

  • -----
  • topic starter
  • Posts: 495
  • Joined: 28 Dec 2006
  • Loc: London - UK

Posted 17 April 2021 - 07:26 AM

Hi everyone

 

I’m planning to build a remote Obs in the Middle East. Cairo to be specific. 
 

So, roughly 30.° N, 31.° E

 

By remote, I meant the country in relation to London, UK. 

 

The Obs will be in a gated compound, about 30 miles west of Cairo, bortle 7ish. It’s the best I can do. 
 

The main advantage is virtually no rain, minimal cloud, and September to May weather is great. June to August it gears HOT, like 36-40C daytime and 25-30C nighttime. 
 

I’m still not settled on dome vs ROR, but since this kind of service is non existent in the country, it will have to be a complete DIY 100%, so dome might be difficult, as there are no companies that will make or sell a dome.
 

The Villa has a garden that is about 25m x 20m. 
 

If I choose a corner in the garden, the villa will obscure the lower altitudes of the WESTERN sky. 
 

I am thinking of building a ROR on TOP of the villa, on the roof? Is that doable, and if possible, what do I need to take into consideration?

 

If I go with the roof, I will have 360 clear skies. Also power and internet will be much easier.
 

Construction is Egypt is 100% concrete with metal rods inside (not sure what to call that), so buildings are very very sturdy. The roof can take any weight, according to the architect anyway.
 

Do I need to orient the ROR in any particular N/S or E/W direction?

 

Since it’s on a concrete roof, will a heavy hollow concrete filled steel pillar bolted to the floor be OK? There will be no one walking on the roof, so there shouldn't be any transmitted vibrations?

 

So many questions, and would appreciate the advice. 
 

Thanks

 


Edited by Oscar Szentirmai, 17 April 2021 - 07:39 AM.

  • archer1960 likes this

#2 archer1960

archer1960

    Viking 1

  • *****
  • Posts: 764
  • Joined: 26 Jul 2011
  • Loc: Southern New England

Posted 17 April 2021 - 08:43 AM

There are a couple of people here who have built RORs on top of their house (or more commonly, their garage). Most commonly, the roof rolls off toward the north since most of the interesting objects are in the south (when you're in the northern hemisphere). It is also reasonable to roll the roof off toward the east, figuring that anything obstructed by it will eventually rise high enough to see anyway, and viewing them early in the night will likely put you in poor seeing. In your case, that would also be toward the city, which would hurt the seeing and light pollution even more, so rolling off toward the east may be the way to go.


  • Oscar Szentirmai likes this

#3 mark77

mark77

    Viking 1

  • *****
  • Posts: 798
  • Joined: 28 Jun 2015
  • Loc: PA

Posted 17 April 2021 - 09:22 AM

If you are doing a 2nd story to an existing structure, you must figure out a way to get a pier down to ground level and isolated as best as you can from EVERYTHING.

 

That is the single biggest issue with adding an observatory to the top of an existing structure. If you just sit a tripod on the floor, it will vibrate with EVERY footstep.

 

Mark


  • Oscar Szentirmai and archer1960 like this

#4 archer1960

archer1960

    Viking 1

  • *****
  • Posts: 764
  • Joined: 26 Jul 2011
  • Loc: Southern New England

Posted 17 April 2021 - 09:29 AM

If you are doing a 2nd story to an existing structure, you must figure out a way to get a pier down to ground level and isolated as best as you can from EVERYTHING.

 

That is the single biggest issue with adding an observatory to the top of an existing structure. If you just sit a tripod on the floor, it will vibrate with EVERY footstep.

 

Mark

Well, he said it's a concrete roof with nobody walking around it, so I'd bet it will work ok.


  • Oscar Szentirmai likes this

#5 Oscar Szentirmai

Oscar Szentirmai

    Messenger

  • -----
  • topic starter
  • Posts: 495
  • Joined: 28 Dec 2006
  • Loc: London - UK

Posted 17 April 2021 - 12:23 PM

There are a couple of people here who have built RORs on top of their house (or more commonly, their garage). Most commonly, the roof rolls off toward the north since most of the interesting objects are in the south (when you're in the northern hemisphere). It is also reasonable to roll the roof off toward the east, figuring that anything obstructed by it will eventually rise high enough to see anyway, and viewing them early in the night will likely put you in poor seeing. In your case, that would also be toward the city, which would hurt the seeing and light pollution even more, so rolling off toward the east may be the way to go.

ahh...excellent point. I never thought of the direction where the city is. 
 

Yes, Greater Cairo with all its light pollution is DIRECT EAST. 

 

So you are suggesting the roof to roll off to the EAST?


Edited by Oscar Szentirmai, 17 April 2021 - 12:26 PM.

  • archer1960 likes this

#6 Oscar Szentirmai

Oscar Szentirmai

    Messenger

  • -----
  • topic starter
  • Posts: 495
  • Joined: 28 Dec 2006
  • Loc: London - UK

Posted 17 April 2021 - 12:25 PM

If you are doing a 2nd story to an existing structure, you must figure out a way to get a pier down to ground level and isolated as best as you can from EVERYTHING.

 

That is the single biggest issue with adding an observatory to the top of an existing structure. If you just sit a tripod on the floor, it will vibrate with EVERY footstep.

 

Mark

Hi Mark

 

The villa is already 2 stories, and the ROR Obs will be on the roof, so practically on the third floor. No one will walk there after I set it up. 
 

Doing the concrete pillar thing will not be possible. 
 

My only option is a DIY hollow steel pier bolted to the concrete and filled with some kind of cement. 



#7 Oscar Szentirmai

Oscar Szentirmai

    Messenger

  • -----
  • topic starter
  • Posts: 495
  • Joined: 28 Dec 2006
  • Loc: London - UK

Posted 17 April 2021 - 12:29 PM

Well, he said it's a concrete roof with nobody walking around it, so I'd bet it will work ok.

Yes. That’s all the misses will allow. It needs to be completely concealed and a concrete pillar through the 2 floors into the ground is not possible. 
 

Are there any plans online I can use or show to our architect to build the ROR, and also some kind of design for a steel pier?



#8 archer1960

archer1960

    Viking 1

  • *****
  • Posts: 764
  • Joined: 26 Jul 2011
  • Loc: Southern New England

Posted 17 April 2021 - 04:24 PM

ahh...excellent point. I never thought of the direction where the city is. 
 

Yes, Greater Cairo with all its light pollution is DIRECT EAST. 

 

So you are suggesting the roof to roll off to the EAST?

That would be my suggestion. That would mean the highest obstruction is to the east, but that's the direction where you won't be shooting low to the horizon anyway.


  • Oscar Szentirmai likes this

#9 Oscar Szentirmai

Oscar Szentirmai

    Messenger

  • -----
  • topic starter
  • Posts: 495
  • Joined: 28 Dec 2006
  • Loc: London - UK

Posted 17 April 2021 - 04:44 PM

That would be my suggestion. That would mean the highest obstruction is to the east, but that's the direction where you won't be shooting low to the horizon anyway.

Excellent. So the long axis of the ROR Obs will be E/W with the ROR sliding toward the east. That’s a start. 
 

Since there are no local companies that do this kind of work, are there any plans online I can give to our architect and engineers?

 

Or are there plans that I can pay a company here in the UK to setup, and use those in Egypt?




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics