Sirius 2.3m or 3.5m dome?

[Amaranthus]

So, I've now settled into my dark-sky site in southern Tassie (yay - the Milky Way is now awesomely rich in Bortle 2 skies, with limiting visual mag of about 6.8). Next step, get an observatory built to set my gear up permanently.

I've basically decided on a Sirius Observatory, and am tossing up between the 2.3m "Home" model and the 3.5m "School" version. (http://www.siriusobservatories.com/index.php/products) I wondered if anyone here had feedback on these - did anyone get the smaller one and then regret it, for instance? It's a big price leap from the 2.3 to 3.5m version (over double the cost), and I'm just not sure I will need the larger one.

I currently use a tripod-mounted AZ-EQ6 but am considering putting this on a pier. My current imaging scopes are 80mm and 120mm refractors and an 8" SCT. I'm definitely going to get a 130mm apo in the near future and am also thinking of a (much) later upgrade to something like a PMX + 8-12" RCOS (...one step at a time, but I want this observatory project to be 'future proof' for the reasonably long term).

I don't need full automation since this will not be a remote observatory, and I like to monitor things -- but I can see the advantage of motorised dome control to keep the slit aligned with where the telescope is pointing, etc. I'd also like the room to set up a desk/chair in the dome. I'm not a 'handyman' by any means, which is why the pre-fab and commercial dome installation appeals to me.

I love any feedback that past Sirius customers might have!

[rustigsmed]

must be exciting Barry!

i have no advice to give other than if they are over twice the price for the 3.5m version and you haven't got a massive scope why not get two 2.3m domes and double the imaging time!?

it would look rather impressive...

cheers

rusty

[Amaranthus]

That's a pretty darned good point Rusty - hadn't thought of that. I could start with the 2.3m, and later 'upgrade' to either a 2nd 2.3m or else a 3.5m if/when I need it -- no rush! I certainly have the physical space for 2 domes.

[rustigsmed]

:thumbsup: sounds like an additional option!

am jealous of those skies! should make for some deep imaging!

[Amaranthus]

The skies here are definitely fantastic. I just wish the clouds would cooperate more frequently :P But then again, I understand the whole east coast has been pretty rotten, weather-wise, this last month.

[el_draco]

I have always believed in building for redundancy. You may end up with a bigger scope at some point in time. If the capital allows it, always go bigger especially in observatories.

Welcome to the Dark side ;-)

Rom

[spinnaker]

I've got a 2.4m KiwiDome, which I believe is based on the 2.3m Sirius? It is heaps big enough for the scopes you've listed. My recommendation would be to go for the smaller option, and put the cost difference into other astro-toys ;-)

[Amaranthus]

Thanks spinnaker.

I got a quote for the freight, comes in at almost $3K just for transport of the kit (which I then need to put together), and unfortunately insurance from Melbourne to Tassie leg is not covered. Given this and the relatively high cost of the whole setup (motorized dome control etc.), I'm still considering other options.

One may be to get a roll-off roof shed constructed. That way I can have 2 scopes side-by-side in the same building. So still thinking...

[rustigsmed]

that is the other option I reckon if you aren't after the 'dome look' a large shed sized roll off roof could fit a few scopes in no trouble at all - line them up!

[h0ughy]

the shipping alone would give you a great roll off roof shed, i own 2.3m and tit gets cosy with a large scope, mount and a computer and monitors, i used a small computer desk iin mine on wheels and set it up on the northern side and had my door entrance near the desk. lookup doghouse and you will find it. strongpong mike has created a dream setup with his 2.3m;)

[Amaranthus]

Thanks Russell & David, yeah, that's what I'm thinking now. I can get a lot more floor space that way, at significantly lower cost. The thing is, this is never going to be a remote automated observatory. I'll be there to roll off the roof, set up etc., and so I can minimise that aspect of automation. And, as noted, use the saved $$ more wisely for investment in toys :D

[AstroJunk]

Do it once and do it properly!

Get the 3.5 with at least dome rotation. I constantly wish I'd got the 3.5 instead of the 2.3.

Personally I think fully automated is the way to go so that I never have to go into it, I just log in from my office and control it from there - but that's my preference.

[Amaranthus]

Sage advice Jonathan. I'd come to kind of the same decision regarding size. But a roll-off roof might suit me better, which could fit say two piers for AP and a Dob for visual, so that is something I'm investigating now.

[Merlin66]

Barry,
If you go down the route of more sophisticated instrumentation and get involved in serious AP.....there's no way you want to sit outside with the mozzies etc. taking a (boring) two hour series of exposures - believe me.

The best thing, when you move from visual, is a suitable sized shed (See the TSO threads) to house the gear safely and then link to a home PC/Laptop ( Teamviewer is free and works well)

In my new location I'm just about to complete a telescope enclosure (Plan E) to weatherproof the C11 and spectroscope and be ready at a few minutes warning to start "data farming"
Think about where you want to be.......

[Amaranthus]

Thanks Ken. The site of my future observatory is 30m from to my house, so even with a roll-off roof design, I can set it up, and then go inside and drive it all via my wireless network (I get a perfect signal out at the scope). The idea was to leave a cheap Notebook out at the scope (under a shelter), and then monitor it from my living room. I do a similar thing now with AP, but I have to break the whole setup down each night and move it all indoors, which is a pain I want to avoid. (and means polar aligning, etc. each new session).

[AstroJunk]

The only issue with the visual set-up will be the wall height which rather restricts the view. A small shed with an end door which rolls off altogether is a neat way of storing a larger dobsonian for visual use.

Whatever your preferred solution, a permanent setup enhances the hobby 1000% :thumbsup:

[Amaranthus]

Height is definitely an issue, I was thinking of a low wall/roof that essentially protected the gear, but then opened up most of the horizon with the roof off (i.e. only crouchable if entered with the roof on). But I haven't yet given up on the idea of a dome (the wind and dew control appeal particularly).

[ericwbenson]

Hi Barry,

Have you thought about how your system will be protected from rain etc? I imagine the weather in Tassie can change very quickly. Once you get going with AP you'll want to take a nap while the AG is running, that nap will turn into deep sleep, to be hopefully woken by an alarm clock to drag yourself outside to close the roof. That's when you find out that clouds quickly rolled in and drenched everything...in addition to the dew that you get every night!

Roll-off obs are great for reaching thermal equilibrium very quickly, are cheaper to build and can house multiple OTAs pointed in different directions, but a dome can close with the telescope pointed in any direction, keeps everything inside fairly free of dew, and gives you much better horizons.

It's somewhat ironic that most professional sites could easily make due with a roll-off roof (very dry, rain is abnormal), but amateurs, who can least afford a dome, get the most benefits from it!?!

After having used a push-off dome for a few years (SkyShed POD + zenith table) to now using an automated 3m ScopeDome, the difference is night and day.

I don't think the size of the dome will be a big factor, you should be in there very rarely once all setup. I had a C14 side by side with a C11 on a PME in the POD, it was workable. But from what I've seen the complicated/expensive shutter motorization of the Sirius 2.3m is not ideal.

Best,
EB

[Peter Ward]

I've got a fully automated Sirius 2.3 metre.

It wasn't always automated.....as the technology didn't exist when I bought it over 20 years ago....

(I actually paid Cyanogen to develop the original Sirius dome controller....but that's another story...)

Over the years it has housed: Meade 10SCT, Celestron 11, RCOS12.5, AP130, AP155, APRHA305, RCOS14.5...many mounts, CCDs & PC's

I worked out it's cost me about $500 a year to own....and figure the gelcoat has another decade (or more) left in it before I have to scrap it.

If you think you'll be using a 16" or larger scope, get the 3.5metre.

If not get the 2.3 with lots of lockers and *fully* automate it. Get a weather sensor & de-humidifier.

Then you can enjoy:

refined polar alignment
zero dome seeing
no wind buffeting
protected instrumentation


Just my 2 cents worth...

[SpaceNoob]

I just put up a 2.3m Sirius in the backyard with full automation cloud / rain / wind detection, power, data, and home security system integration with a Rottweiler for redundancy :lol: . My life has changed..... well it did for the brief moment of cloudless nights. Now I am cursed by clear days and clouded nights.

Very happy with mine so far but it is still a work in progress as it has only been up for around 4 weeks or so. It sits on a raised steel frame deck plus thick merbau decking which I corked on the interior of the observatory. The pier sits on a concrete column that comes up just below deck height. The column goes down to the ground where it is around 1 cubic meter inside the ground.

I run a CDK 12.5 in mine, probably similar tube size to a C14, I wouldn't go much bigger.

[strongmanmike]

Awesome looking setup there Chris :thumbsup: You in Gungahlin?

Mike

[SpaceNoob]

Cheers Mike it has been a mission! I'm out at West Macgregor, just on the edge of the boarder. Your setup is not far from mine I'd imagine ;)

I believe the column design was based on your monolithic structure :lol: .... Can't say I ever intend to dig another 1m deep hole into clay by hand or mix anymore concrete ever again.....

[Paul Haese]

I run both types of roof systems. Roll off and a dome. Both fully automated and both protected from rain, cloud etc.

The roll off roof has killed one Eaton UPS because of the dew. The Dome is great for minimal dew issues. It was not cheap to build though. About a similar price to buy the dome.

The only down side to the dome is you could not have a desk in there. I have a Scope dome which runs on a track at ground level and has an umbilical cord. Though you could mount the dome on a wall and have the umbilical running down near the wall under a false floor. I rarely go into it when it is imaging. I just don't have the need to be in there.

You can buy a fully automated Scopedome 3M for around 12-13k from the Australian distributor. I am not sure about freight, but that does seem like a lot. I can get whole truck loads of materials to a site 800km away for $1200.

Think about going full remote as it will eventually be a want. Staying up night after night to do a long imaging run has knobs on it. The cost outlay is nothing compared to what your sleep is worth. It will also mean you can image from anywhere in the world. Just a thought. ;)

[Amaranthus]

This is where a forum like IIS really shines -- the feedback here (on a financially significant decision) has been tremendous! Thanks to Eric, Peter, Chris and Paul for sharing your experiences and given really sound advice.

Given that I just can't see myself ever getting anything as bigger than an RC12, I reckon the 2.3m with a bunch of pod bays will suit me fine. Yes, I'm convinced now that a dome is the way to go, and although it's going to be more expensive, I reckon full automation is also going to be key, or else I'm going to regret it in the future. Paul, I remember I was very impressed with your talk on this topic in Adelaide a few months back, but at the time thought "yeah, but I won't need to go the whole hog". Now I think maybe I will. Even with a dome right near the house, sleep is nice, and maximising imaging time via weather detectors etc. also sounds sweet.

So thanks. I really value all this.

Paul - who is the Oz distributor for Scopedome? I should check it out before I make a final decision.

I'm also wondering whether I might be best to get a pier installed from the start.

[Paul Haese]

Hi Barry,

I had no idea that you had seen my talk on remote imaging. Glad you got something from it.

Rally (a member here) is the distributor of ScopeDomes here in Australia. His sig here is simply Rally.

As for pier, you will need to consider how big the scope is and which dome you will go with. With that thought out there is no reason you cannot go and start this straight away.

[Amaranthus]

Yep - it was when I was still living in Adelaide. I'm the guy who bought your 12nm narrowband filters!

Is there any particular pier supplier that is recommended?

[Paul Haese]

Sorry Barry, gold fish effect occurring there. :sadeyes: It is now indelibly etched into my brain that you are the Barry I know. :thanx:

I had my piers made up. I recommend you go to a local steel fabricator and ask them to make you one up. They will want a drawing to show what you want. My recommendation is go at least 8" in diameter and if you can 10mm wall thickness or more.

[Neil]

G'day Barry, I have the Sirius 2.3m Dome only mounted on a colourbond steel framed shed 6x3m.Obviously this gives me plenty of space, but you can expect to pay twice as much as the 2.3m observatory. Clear skies.:D:D