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Started by jhapeman, 04/02/2002 08:12PM
Posted 04/02/2002 08:12PM Opening Post
After yet another winter where I think I may have permanently sterilized myself from exposure to Wisconsin's sub zero temps, I have decided I must have an oservatory before next winter. The wife has signed on the PO, so it is a go.

What I can't decide is, roll-off roof or dome? I am looking from input from both camps, and maybe someone who has done/used both. I want to keep the scope and electronics (computer and CCD) permanently in the observatory, and hope to remotely run most of it since I mostly image. This makes me lean more towards a dome. Aesthetically, I think a roll-off roof might look better....

I will have a variety of scopes in there, but probably no more than one at a time. Largest scope for now is the FCT-150, which is about 1.5 meters long.

Comments, thoughts, etc?


Jeff 8O
Posted 04/03/2002 10:39AM #1
I have both. My backyard observatory is a dome and my dark-sky observatory is a roll-off roof. Both have their pros and cons - I prefer the dome. The dome is much better at shielding stray light (as you’ve seen over the CCD Imaging forum) and wind.

The dome I’m using is an HD-6T from Home-Dome. It’s a self-contained 6’ dome with 45” walls and a small door. It works very well but has a few oddities. The door also serves as part of the dome rotation rail. This means in order to rotate the dome the door must be shut. This is a problem if you just started a long exposure and want to leave the dome! In my case I run the camera, mount, etc from in the house so it works fine.

The 6’ dome *barely* holds the AP155. It will soon be replaced with a 10” RCOS which will be snug as well. And there is precious little room for a person in the dome once you’re all rigged up.

If the 6’ dome matches your needs I would recommend getting the dome alone and build a small building underneath it. I would give you more wiggle room, cost less and get around the entry/exit problem while imaging.

Posted 04/05/2002 01:57PM #2
I have a 16X16 foot roll-off roof and I love it. My understanding is that domes can (but not always will) have seeing problems. My building in Sonoita AZ (about 2 miles from Herb) cools of quickly after the roof is opened. It was designed for a 22" f/5 Newtonian but that scope had some problems so now have a C-14 on older AP1200 on a pier in center of floor (will eventually have a 17" RC in it). There are a few problems or issues: since AZ can get some wind, if it is windy I can't open the roof (I don't want to have to retrieve it from the next county). Also, I had to get a permit and engineer's stamp for the roof hold down system. Thus far it has lived through a 72mph wind gust (it is designed to stand 80mph winds). Depending on neighbors and such, a dome might not fit into the neighborhood very well. Also, at least in theory, a roll off might be cheaper than a dome.

Posted 04/07/2002 02:26PM #3
I would recommend a HomeDome 6' with the transition piece, placed on top of your own stick-built structure. My structure is 10' X 10' and I've had 5 adult visitors inside with no problem. My scope is an FS-128 (about the same length as an FCT-150) on a GEM. The standard domes with round walls (6') are OK for fork-mounted SCT's, but a refractor on a GEM requires considerably more room due to the "swing" involved while moving.

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