Roll off vs Dome Observatory

[Mark G]

This spring I'm hoping to break ground on an observatory. I've bought backyard observatory blue prints for an 11' 6" x 11' 6" roll off over a decade ago. So its about time. I'm thinking of adding a warm room to enlarge the structure. But before I go there I'm interested in those that have built their own. What type did you build and why?

I look forward to hearing back from folks. TY in advance.

[bluemax]

Mark, I had a dome type for a while and was of course, way better than not having one! But, doing it again, I would go with roll off as I always had issues with dome rotation software/hardware. Others may disagree but that was my take. Especially problematic when doing various alignments and object searches, as the dome would have to move quite a lot; back and forth repeatedly, etc. A roll off obviously would not have this.
Even in cold weather, the dome was almost as cold as outside so, comfort of dome vs roll off does not seem much different. That's my take anyway.

[mark.m]

Mark:
I'm using a clam-shell style roof on a very small building.

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Since all my observing is remote (inside my house), the building is quite small and there are many telescope orientations where it simply isn't possible for a human to squeeze into a position where eyeball observing is possible. However, there may be a couple of lessons learned from this:

1. Plan on upgrading the scope/mount at some point in the future; size the building and roof so you have margin. My aperture upgrade options are limited because clearance around the scope is measured in inches
2. Frost line and building code call for a 40" foundation around here. My pier concrete foundation goes down about 48" and it isn't quite deep enough (or I don't have enough concrete mass at the lowest depths). Every year, I see a noticeable change in polar alignment in early January and then a second change sometime in March as the ground freezes deeply and then thaws.

- Mark M

[Mark G]

Thanks for the in depth advice. I've a lot to ponder on. I like the clam shell idea but leaning towards a roll off atm.

[Pete]

This is a very old URL but a wonderful compilation of different amateur observatories. Some are unlinked due to age but it's probably the best resource on the web for getting creative. Do check out the Outhouse Observatory under "Other Designs".

https://nineplanets.org/amateur-astrono ... rvatories/