Selecting the Right Inflatable Planetarium II: 

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Entrance Systems

My previous blog (link) began this discussion of inflatable planetarium features. My goal is to discuss various aspects of the domes to help customers in selecting the right product for their needs. My first blog was pretty basic: I discussed the dome itself.

Now let’s consider how we get in it. We will discuss tunnels, vertical zippers and airlock door systems. Of course, the challenge is to get the audience in without letting light in—at least not letting too much light in during the program. Another concern is not letting too much air out, deflating the dome at the wrong time.

Some manufacturers offer an entrance tunnel that audiences must crawl through. It is simple, and probably the least expensive option. Bends in the tunnel prevent light from seeping in. This is promoted as a fun, kid friendly way to enter, increasing anticipation for the experience inside. On the other hand, educators may see the activity as disrupting discipline and making it more difficult to get students to settle down for the program. This method may also be physically difficult for some students, teachers and other adults.

Perhaps the most common entrance design involves a vertical zipper to close the opening and seal out light. Velcro is sometimes offered instead of a zipper. Again, it’s pretty simple (and therefore inexpensive) and can be incorporated directly into the dome cloth. The downside is that a lot of air pressure may be lost as someone is entering or exiting, causing the dome to deflate. Entrance and exiting needs to be paced to prevent too much deflation–which can be frustrating for everyone involved. Light floods in at the same time, disrupting any program in progress. On the other hand, discouraging late arrivals and early departures makes for a smoother presentation so some may see this particular issue as a plus.

Entrance Systems

I found neither one of these designs satisfactory and set upon devising a new approach for Go-Dome products. The result is the Go-Dome Curtain Valve Entrance System. This is comprised of two pairs of curtains made of inflated tubes. The curtains part in the middle for entry and exit then it quickly and naturally reassumes a closed position. Audience members step through one set and into a small vestibule-like space, then the other. When closed, a negligible amount of air and light passes through—it’s not enough to deflate the dome, and some find the air exchange beneficial as it keeps things from getting stuffy inside. We also build vents into the system to prevent over inflation of the dome. In most cases, any light seepage through the gap will not be enough to interfere with the program, but we provide Velcro straps and a zipper that can be used if a tighter seal is desired.

Curtain Valve Entrance Systems for four and five-meter Go-Domes have a six-foot clearance, reducing the stooping or crawling (in the case of tunnels) necessary with other entrance designs. Larger Go-Domes feature our new seven-foot entrance. With little risk of dome deflation, individuals do not need to rush through. The curtains attach to a vinyl floor designed to reduce trip hazards. A special feature of our design is the ability to detach the curtains at the floor. Once detached, two people standing at the sides can part the curtains to allow wheelchair access into the dome. We are particularly proud of this innovation, and it led to another accessibility-oriented product.

We now offer an entrance specifically designed for wheelchair accessibility. It is constructed of rigid vinyl as a custom, stand-alone inflatable structure. Once inflated, it remains sturdy and in place until the deflation valve is opened. The doors are inflated as well (this is an inflatable planetarium, after all), but swing open like a typical house door. No special assistance is needed with the Go-Dome Wheel Chair Entrance. All styles of Go-Domes can be fitted with this entrance.

We took this idea even further with our Zodiac Series of Go-Domes.  Building on the structure of our Wheel Chair Entrance, our Zodiac Series features two separately partitioned airlocks accessed by pairs of inflated, swinging doors. Each airlock is large enough to accommodate 15 standing people. This facilitates traffic flow as one can serve as the entrance and the other as the exit.

Well, so far we have discussed inflatable planetarium domes and entrance systems. Next up we will get into a few other things, including the all-important dome screen.

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Gary Young is President of Go-Dome since 2005 and President and CEO of Avela Corporation, the parent company to Go-Dome.