Dome vs Roll off ?

[Astrokev]

I've been "planning" building an observatory for, ooh, probably a few decades now. The dream is still alive.

For much of the last few years I've been following roll-off build threads with great relish, thinking that this would be the approach I would adopt. I'm reasonably proficient at Bodge-It-Yourself, so would enjoy such a project.

Then, a week or so ago, my lovely wife suggested the idea of getting a dome (and building the base, pier, rest of the install myself - thereby qualifying for inclusion in this forum!). Although more expensive (probably), her logic was that I never have enough time to do anything, and my roll-off dream shed was at risk of never getting started, let alone completed.

So, my dilemma - what should I do????

If I do decide to "Go-Dome", I'd be really interested in recommendations from other dome-ers regarding suppliers, quality, pricing, etc, etc, to give me a few pointers.

Looking forward to your guidance and wisdom......

[Jessun]

Got neither but I'd imagine that a dome would be ideal - less wind basically, possibly less dew. Then there's is the matter of being able to comfortably move around the telescope should you wish to - rather than just building it for a remote imaging setup - pushing the price for a larger dome.

Interesting to see what you decide on!

[ollypenrice]

To be honest small domes seem to me to offer nothing much more than sex appeal - they do look more like observatories! When they are small they offer no headroom in the space where you need it. It can be said that they protect from stray light and wind but they also need organizing in terms of keeping the slit orientated. This may mean motorizing. If you navigate the sky manually they are a nightmare because you can't see enough sky. You miss all the shooting stars, too.

I've built five roll offs of different kinds and think they are easy to make and nice to use. I do have a dark site, though. Bays for computer or whatever brin,g he footprint down big time.

Olly

[michaelmorris]

As I see it, the advantages of a dome over a roll off are:

Better dew protection

Better at excluding stray light and glare

Better priotrection form the wind (for both you and the scope)

The potential down side are:

Less sky to see

More hassle

It shouts "Look, there's expensive stuff in here"

Chimney effect of heat escaping through the slit > poorer seeing

Personally, I went for a roll-off roof with high sides (good wind and stray light protection) and some good dew heaters.

You pays your money and you makes your choice.

[Gina]

I agree with what's been posted. I chose a roll off system for three reasons :-

1. Cost - domes are very expensive.
   
2. Ease of construction
   
3. Security - as said above, domes shout "I contain very expensive equipment".
   

[carastro]

I have a POD and whilst I love it, the biggest drawback of this obsy is that the dome only pulls back to the Zenith.

Most of the year this is not a problem as most things I want to image do not pass directly over, but it is a problem when Cygnus is high and I have had to resort to pitching my kit on the lawn during August as additionally many of the bright alignment stars are overhead as well. I also like the bays in it in which to keep your kit and a work surface for the laptop. You do not get this option with other domes and I can't imagine how difficult it must be to store kit and erect a table/work top with circular walls. Also the Slotted dome needs to be motorised if you are imaging and need it to rotate. I don't have this problem with the POD as half the dome is open.

It does look neater in the garden than a large roll off rook obsy with extended legs, but I do worry though about it being an indication that there is expensive kit inside, and on reflection if I was to start over again, I think I would go for a roll off roof with a warm room.

Carole

[carastro]

Excuse typos. obviusly roll of Roof and not Rook.

[r3i]

I agree with what's been posted. I chose a roll off system for three reasons :-

1. Cost - domes are very expensive.
   
2. Ease of construction
   
3. Security - as said above, domes shout "I contain very expensive equipment".
   

I think those 3 points sum it up for me too - my observatory construction project is imminent and I'm going to be venturing down the ROR route.

[Gina]

Having the roll off roof and attached warm room means the whole thing just looks like a large garden shed or (two sheds bolted together)

[Gina]

Must pop into our neighbour's field and take a photo or two from that angle

[callump]

I currently have a RORO observatory, but am having the kinda counter-intuitive plan of converting it to a domed observatory, or building a separate domed observatory and knocking down the RORO.

Currently the roof does not roll - the external wooden rails rotted (poor maintenance on my part), and need replacing - not a big job really, though.

But the area the roof rolls over is dead space, and could be better used in the garden.

So, if you don't have a lot of spare space in your garden a dome is a good option.

I will be doing a DIY dome - either along the lines of nytecam's or astronomyasylum.com - but still not decided whether to put a dome on the current, or build a new one.

The main problem with the existing site, is the trees that have grown over the 10 years since it was placed there - a new site would have better aspect.

Callum

[RogerTheDodger]

If I ever get the chance to build one it'll be like Gina's or Malc-c's.

[The Sailor]

To be honest small domes seem to me to offer nothing much more than sex appeal - they do look more like observatories! When they are small they offer no headroom in the space where you need it.

What a load of tosh, sorry to be so critical of your comment but I have a "small" dome on my observatory and it is great, loads of room. I obtained a SW 200 a couple of weeks ago and although I cannot now put that extra coat of paint on it fits perfectly. Now I know it has been described as part Dalek but I don't mind, it has helped me enormously, was cheap to get made and is fun (for others) .

Jim

[pete_l]

For the price of a usable sized dome, you could get a handyman in to build you a RoR. Though I think the concept would need a bit of explaining before they got the idea.

"Yes, I want a shed, but I want you to cut the roof off. And I want you to make a frame and add rollers to the roof so that I can slide it open and closed."

[AndrewG]

Although I agree with most posts my personal take was that I didn't have much choice as to get the best views my obs had to be installed in the bottom corner of my garden and a roll off roof would not fit in. I must say that I am more than pleased with the design by Pulsar and Gary / the team did a first class job and I highly recommend them to anyone; although you do need the additional storage bays (mine are located out the back).

With regards to security the Obs is alarmed and insured albeit I have been slightly paranoid regarding theft (on a few occations the alarm has been set off by moths which triggers my mobile response and a possible heart attack! ) hence I have only found the lack of "blending in" (plus the cost) to be the only real downside, notwithstanding that I have introduced plant screening to make it less noticable.

Andy

[Gina]

Practical, easy to use, as much sky available as possible and not costing too much - that's the way I see it And it also needs to fit into the environment and not upset neighbours or planners. Neighbours can be very um... well, you know! We even had one several years ago that complained to the council that we'd cut brambles out of one of our hedges!

[George]

But the area the roof rolls over is dead space, and could be better used in the garden.

Callum

Im lucky in the fact a railway is at the back of my observatory so the roof rolls over the fence onto the railway embankment, its that overgrown that my little incursion cannot be seen from the track below

[Gina]

You could paint it green Andy - I guess Or get some spray paint and use your artistic abilities to paint branches and leaves on it... Or attach a comouflage net to it... Or...

Is the hatch easy to open? Is the dome easy to turn? Do you have it motorised? If motorised, do you have it automated to keep the gap in front of your scope?

[malc-c]

I opted for an ROR observatory for the following reasons

• Even the chavs and yobs of today associate a dome with telescopes and thus in a town environment at least, advertises the fact that there is something of value inside. A ROR looks like a shed and most of the aforementioned arn't interested in lawn mowers or garden sheers
  
• For the same amount of money you get more space and the option of adding a warm room.
  
• I designed mine so that the roof rolled over the top of he warm room. This means that the structure looks like a shed, but with a slightly funny roof when closed.
  
• Design and build - simple framework makes the design and construction simple with no more than a chop saw, drill and screwdriver. Easy to work with, wood is forgiving for drilling holes and nailing stuff to
  

Whilst Andy's dome looks cool, look where it's located. It fits in nicely with the trees and other shrubs in the corner of his garden. A ROR would look out of place there. As would placing the dome in an open setting in the middle of a lawn. The point that I'm trying to make is that it's impossible for anyone to suggest to Kev what he should go for, as we don't know the intended location, his practical ability, or particular needs (like keeping warm in the control room )

[Carbon]

If I had a large secluded back yard a dome might have been an option for me.

I built my ROR to look like an ordinary garden shed to blend in with its surroundings. A large white dome in its place would have been too obtrusive.

[Digz]

I'm intrigued in the two comments that a done offers better dew control - how so?

For me the things to look at would be:

Space - a dome is usually more compact as you don't need space to roll off the roof;

Cost - domes tend to be more expensive, but making a ROR yourself could have the potential for a costly mistake if your like me and can be a bit hasty;

Security - a dome can shout out look expensive kit whereas a self built ROR can be more discrete. Having said that both options can and should be made secure with adequate locks and alarms.

For me I think I have favoured a ROR as I know I have the skill to detail (building it will be another matter) and look forward to the challenge of constructing it.

[AndrewG]

Gina thanks for the advice I may be going down to the army stores this weekend ; if it is interest to anyone Pusar can make the dome in Green, albeit it is not as good as white given the dome will then absorb more heat in the day!

Thanks Malcom for the comment, just to agree I did want to have a roll off roof but by garden layout and positioning just didn't make it possible; notwithstanding that I have got used to it and belive it or not my friends and even friends kids all think it looks cool.

With regards to neighbours I am quite lucky; last week my nextdoor neighbour even let me cut down the tops of his Pear Tree's so not to block any views!!

Andy

[AndrewG]

Oh Gina forgot to reply on my last post, answers are as follows:-

Hatch is easy to open as long as you pull on the correct side of the rope pulley, I have marked mine with tape to make it easier.

The dome can be turned with one hand as it runs on nylon / plastic wheels.

It isn't motorised but maybe one day albeit as I stay in the dome during photo's it is not hard to just move the dome now and then; the dome is the latest Pulsar design and I believe the hatch is larger than the previous version.

I did have a few extras such as the dome security system which prevents strong winds or people taking the top off!

[Gina]

Thanks Andy Sounds pretty good

[Davey-T]

At the risk of upsetting the traditionalist wood shed ROR builders. (incidentley have you seen the price of wood lately) I made my ROR from a Keter plastic shed and if I'd had a plan

to start with, and a solid base, I could do the whole thing in a weekend.

Pictures somewhere on obsy forum.

Dave