Science On a Sphere System Description and Guidelines and
Recommendations for Setup

The goal of this document is to describe a typical setup for Science On
a Sphere and discuss very generally, the lessons that NOAA has learned
while using Science On a Sphere in conferences, conventions, classrooms
and presentations.

# Science On a Sphere -- Enclosure Layout and Design Considerations

## **Spheres**

> The sphere size is 68" in diameter. Other sphere sizes are possible,
> but would require custom engineering (at additional cost to the SOS
> recipient). Description follows:

-   The 68" sphere is built to come a part at the equator in to equal
    halves. There is one seam to hide and it's very straightforward
    process to hide it. The 68" sphere is the sphere that we typically
    use for shows, conferences and conventions. The current version of
    these spheres weighs in at less than 50 pounds.

The sphere is attached to the ceiling or suspension structure via a
three-point suspension system. The cables are rated to hold many times
the weight of the sphere. A three-point suspension system is used to
hold the sphere in place and reduce lateral movement. If the sphere
moves, then the images become un-focused. The cables are strong, yet
small enough to blend into the background. The suspension cables come
with the sphere.

**Sphere Placement**

The sphere is positioned within an enclosure, surrounded by four video
projectors. The projectors form a square footprint around the sphere.
The distance of the projectors from the center of the sphere can be
obtained with the following formula for a sphere of radius, "R": 6.61 x
R. Looking down from above, the sphere sits in the center of a box that
can be formed by drawing lines between each adjacent projector. The
lengths of the sides of this box can calculated by the formula: 2 x 6.61
x R / sqrt(2). A 68" sphere needs a square foot print of about 27 feet.
See the diagram of the Science on a Sphere standard setup.

#### Projector Placement

> As described, the projectors are at the corners of a virtual box with
> the sphere at the center. The projectors should be mounted in a way
> that allows for a 3-axis adjustment (x, y, z planes). In our lab and
> for our traveling exhibit, we have successfully used a gear driven
> tripod mount, on a tripod, or permanently mounted to a structure to
> provide the necessary adjustments. Other mounts are available that
> might be more appropriate for a permanent exhibit. We have also found
> that, due to what is believed to be differences in projector lens,
> that the projectors need to have some flexibility to adjust the
> distance to the sphere, by as much as 4" to 10", so the projector
> mounting mechanism must support this type of lateral movement. The
> heights of the projectors must match the height of the equator of the
> sphere.

#### Sphere and projector height

The height of the sphere is somewhat arbitrary however there are some
best practices that should be followed. We have found through our
numerous demonstrations, that the height at the equator of the sphere
should be about 84" off the ground. This serves two goals, the first
being, that that the projectors are also 84" off of the ground and this
height somewhat minimizes the shadows that occur when an individual
walks directly in front of a projector. This is clearly dependant on the
height of the individual and their closeness to the sphere. The other
goal served, is that the sphere isn't too high for viewers. By stepping
back 4 to 8 feet, the viewers can still get a view of the northern part
of the sphere, yet it's not so high as to not allow a viewer to walk up
very close to the sphere and get a feeling of size, scale and
proportions of the globe.

**Sphere Viewing Considerations**

The four-projector design of Science On a Sphere has some inherent
limitations, the main one being the blackout areas at the top and bottom
of the sphere. The blackout area amounts to a small square at the very
bottom and very top of the sphere. This is the area where the light rays
of projectors cannot reach from their current location. With the sphere
at the recommended height, this blackout area is difficult to see and is
generally of little issue even if someone happens to lean over and see
the little blank area at the bottom.

#### Ancillary Monitors

> The Science On a Sphere system can display ancillary information that
> is synchronized with the data being displayed on the sphere. The
> ancillary information is piped out one of the VGA outputs from the
> control system and can be split and directed to other monitors in the
> enclosure or somewhere near the sphere. In the past, we have used this
> technique to drive PowerPoint-like presentations onto two plasma
> display monitors to provide a more detailed description of the data on
> the sphere. The slide file format is a simple JPEG and can be dumped
> out from numerous presentation packages.

### Synchronized Sound

> The Science On a Sphere system can play sound files, synchronized and
> associated with each discrete data set. As the system switches from
> one data set to another, the appropriate sound file is piped out the
> sound card on the network control computer. This feature provides the
> foundation for running Science On a Sphere in an un-attended mode of
> operation, where the sphere is displaying data in sequence, with audio
> accompaniment. For our traveling exhibit, we pipe sound into a simple
> mixer and send the sound to speakers positioned around the perimeter
> of the enclosure. A wireless microphone system can be tied in for
> other, narrator lead demonstrations.

### Light Levels

> We don't have a lot of information on acceptable light levels for
> Science On a Sphere viewing. Any discussion regarding acceptable light
> levels is fairly subjective. The projectors that are used are bright,
> 3300 lumen projectors. The projectors provide significant amount of
> illumination and contrast, even in well-lit areas, however being able
> to control some aspects of the light conditions in the enclosure will
> be important. The system looks it's best when viewed in fairly dark
> conditions, one in which the sphere appears to be suspended in outer
> space.
>
> The system has been setup in at least one lobby, but there was minimal
> outside light. At on conference we attended, the area around the
> sphere was flooded with high levels of ambient light, from high
> ceiling mercury vapor lamps and the system still looked very sharp and
> attracted a constant stream of spectators.
>
> In terms of direct outside light from the Sun, hot spots, sections or
> spots of light directly on the sphere may be very distracting to the
> viewers. Keeping direct light off of the sphere surface is important.
>
> For those that have seen our basement exhibit of Science On a Sphere,
> at FSL in Boulder, we have some Exposure Values (EV) taken from a
> Gossen Luna Pro Digital light meter, set to ISO 100 (it's the best
> that we could do for the time being):
>
> Near the sphere, lights on: EV 2.2 to 2.8
>
> Reflected light coming off of the sphere: EV. 6.3

### System Noise and Cooling for the Equipment

> The projectors generate a small to moderate amount of noise due to the
> cooling fans. The projectors also generate a fair amount of heat for
> their size. The projector enclosure will have to maintain adequate
> cooling and ventilation for the projectors. The Dell computer systems
> generate very little noise, but a significant amount of heat from rear
> exhaust fans. The standard configuration consisting of five computers
> needs to be kept at an ambient air temperature somewhere in the mid
> 70's with adequate air flow away from the CPU cases.

#### Floor and Seating

> A carpet floor would be desirable for kids to sit down on and to help
> reduce sound echoes. Many times, when children come in for a field
> trip or are their as part of a tour, they immediately sit down on the
> floor.
>
> Generally presentations led by a facilitator involve the audience
> walking around the sphere. However, some audiences don't want to walk
> around the sphere and are content to just stay in one place. In
> several venues, we have had people that just come in and find a place
> to sit (usually on exhibit furniture). It might be nice to accommodate
> a few places for folks to sit down in chairs or benches even though
> these audience members won't get the same, rich experience.

### Walls

> There might be an advantage to having some kind of smoked glass mirror
> on the inside of the enclosure. At one of the venues, we had a room
> that had T.V monitors and a wall of glass bookcases. Seeing the sphere
> reflected off the glass bookcases was very spectacular and seeing the
> sphere reflected in the curved glass of the black, powered off T.V.
> screens was even more amazing to see.

## **Audience**

Over the past year, Science On a Sphere has been seen by thousands of
individuals, from young children in grade school to adults. The venues
have ranged from very casual to extremely structured. In all cases, NOAA
has used a narrator-based approach to show Science On a Sphere. Results
with this presentation method have been extremely positive. The space
setup is generally in a 30' x 30' enclosure, sometimes open on the sides
in the case of our traveling exhibit or closed in the case of smaller
rooms we've used. During presentations, having an audience of about 30
people is optimal. Audiences of 50 to 70 become uncomfortable, but they
are also manageable with proper assistance for crowd control.

During presentations, the facilitator can use a remote control device to
manipulate the animations being shown on the sphere. The remote control
can perform standard VCR like functions such as stop, play,
fast-forward, reverse, etc. On some visualization, the remote control
can be used to dynamically change the angle and tilt of the display to
focus audience attention on a particular area or feature on the sphere.

A random observation is that children younger the 10 seem to immediately
want to touch the sphere and then crawl on the ground underneath it to
see what is at the bottom. In a museum setting, it is recommended that a
railing or barrier of some kind be installed to restrict audience
members from touching the sphere. Touching the sphere can result in
sphere movement, pose a safety issue, and generally detract from the
presentations. Children tend to want to jump up and see if they can cast
shadows on the sphere via the projector light. Generally this is minor
problem.

From evaluations of SOS in public places the following has been
observed:

-   Visitors are enthralled with SOS, so much so that they generally
    don't look at surrounding flat-panel displays with other imagery on
    it.

-   Visitors are generally curious about the technical aspects of the
    sphere..

-   Visitors liked the aesthetic value of the brightly colored data that
    was shown on the sphere.

-   Visitors responded very positively to a live presenter to guide them
    through the data shown on the SOS. For these presentations the
    audience would stay for 40-min presentations.