To tilt or not to tilt a dome
- Hi all,
We are leaning (tilting?) toward a tilted dome, but are trying to decide on
the degree of tilt. None of us is really interested in a very steep tilt.
It's only a 30 footer. I have have heard of everything from a few degrees
to twenty-something. I am intrigued by the approximately ten degree tilts
I have heard of. Many of you have tilted domes. I would love to hear pros
and cons. As in all things with the process, money will come into play at
State Chair, Great Lakes Planetarium Association (GLPA)
University of Michigan Museum of Natural History Planetarium
Room 4508 Museums
1109 Geddes Ave.
Ann Arbor, MI 48109
First dome I ever worked in was in Roanoke VA at the Hopkins Plantarium. It is a 40-foot dome tilted 41-degrees. Now you have heard of much more than 20-degrees!
The purpose was three fold, there are 140 seats that need a clear view of the sky (Spitz 512) the five-pan, triple stacked slide system, and the 35/70mm film projector. The design is quite unique and was fun to work and learn in. It got me where I am today.
There are a few other unique items that I won't go into here.
I have worked in flat, tilted and extreme tilted. My favorite is what I have now, slightly stair stepped seating for 160 and a 12.5-degree tilted dome. I believe it to be the right thing for a dome that is used as a theater, planetarium, lecture and classroom facility and more.
My choice: uni-directional seating and 10 to 15 degree tilt. I like both Spitz and Astro-Tech domes equaly.
This is my two cents, let me know if it helps.
Univ. of Louisville
- Hi Matt,
I am probably biased, since ours is a tilted dome, but I see a lot of pro
points for tilted domes. :)
We have a 15 degree tilted dome and uni-directional seating. Nowadays, most
of the fulldome shows available are more suited for unidirectional seating.
Some of the other planetaria in India, which started out with concentric
seating and optomechanical projection systems, ripped out their seats and
converted to uni-directional seating when they upgraded to fulldome
projection. Others are trying to roll their own shows to suit their
concentric seating. So, in our case, the uni-directional seating and the
tilted dome seems to be a good choice.
There's a pic of our theatre at
With a tilted dome and uni seating, the horizon can go lower down than with
concentric seating without tilt, since stepped seats mean that the people
in the back rows are not blocked by the people in front. The seats can be
more upright, tilting at an angle rather than completely reclining, too.
This could help with increasing seat density, too.
There were some older threads some time back about concentric vs
unidirectional seating, tilted domes, etc those may also be relevant for
Sri Sathya Sai Space Theatre
AP - 515134
Here's one caveat to consider with a tilted dome. Because of the tilt, you
will not have a continuous horizon completely around the dome. This isn't a
problem if you're only presenting fulldome video, but it can be
problematical when giving star presentations. For example, when I give a
lesson on the seasons, I like the students to track the sun's apparent
motion from horizon to horizon. With a tilted dome, if the students are
facing south, this cannot be done properly when the sun is north of the
celestial equator, because the the horizon stops at the east and west
Just something to consider.
Retired & Domeless