ORIGINS OF THE IDEA
In 1985, at the Spitz Summer Institute, fellow
planetarian Jordan Marche listened to my wife and me talk
about our dreams of bringing a planetarium to central
Maine. At that point we were thinking big, a new
permanent facility. Jordan suggested that, perhaps as a
stepping stone, we should consider buying a Starlab
portable planetarium. Maybe you could run it as a small
business he said. Perhaps, we agreed politely. We looked
at each other and neither of us wanted to settle for just
a Starlab. Our dreams were bigger, or so we thought. But
like so many good ideas, this one took some time to sink
in.
On the long drive back to Maine we tossed around
Jordan's idea. We knew that to make a living and not go
absolutely stir crazy with a Starlab, we would have to
design some peripherals that would enable us to expand
our offerings. We wondered, how much stuff can you
reasonably tote around with a Starlab? How could we make
it modular, reliable and easy, as well as quick to set up
and take down? So we made a set of criterion that any and
all peripherals would have to meet. First, we couldn't
afford to buy or build things that were for too specific
a use. In other words, we didn't need any special effects
projectors that would be good for only one show.
Everything had to be useful in numerous different show
productions. Second, whatever the final configuration,
everything had to be quick and easy to set up. We decided
that total set-up time should not exceed one hour, and it
would be even better if it were between thirty and
forty-five minutes. Third, we wanted our finished product
to be modular; in other words, easy to set up without
lots of projector aligning required and without carrying
around lots of small loose projectors. Everything had to
be attached solidly to, or inside of, carryable
cases.
At this point we made a wish list of what would be
nice to have. Then we pared things down to just those
things that met the above criterion. Then we pared it
down further to what we could afford.
THE HARDWARE
The selection process lead us to purchasing four
Ektagraphic IIIe slide projectors. Two of these would be
in a dissolve rack that would be built into a movable
case; these two projectors would provide a cross fade in
the southern sky. The third projector would go into a
second projection case that would project to the
southeast. The fourth projector would be placed in the
center of the planetarium beside the star projector. It
would project toward the west.
We also decided on fifteen special effect projectors.
We bought four Talent brand projectors from Sky Skan,
Inc., of Nashua, New Hampshire: an aurora, a sunset, a
meteor shower, and an evolution of a star. The Talent
brand projectors were ideal for a portable planetarium
use because they are physically small, low wattage, and
quiet (they lack fans); unfortunately, Steve Savage of
Sky Skan says he no longer carries them. I also bought a
rainbow projector and a strobe for lightning flashes,
explosions, etc. Purchasing ready made special effects is
relatively expensive, so I built a number of special
effects myself, utilizing old film strip projectors,
spare parts, and specifically purchased parts. These
projectors include a rotating earth, a slide rotator with
an anamorphic lens, a slew, a blur wheel, clouds, rain,
meridian, milky way, and a shadow panorama projector.
Recently, we have also expanded our hardware to include a
VCR with a LCD video projector.
To contain and control all these projectors I designed
a console. The console was built similar to the control
consoles I worked with at the two permanent facilities
that I had been associated with, the Francis Malcolm
Institute's planetarium and the Jordan Planetarium at the
University of Maine. I had been involved with the design
and construction of the consoles at both of these
facilities, so for my own portable console I simply
scaled down the size and the number of controls. All the
special effects were then bolted into place either inside
the console or inside the modular box that contained the
slide projector that projects to the southeast. In this
way, setting up became very easy, just put the modular
boxes and console in place, connect the cables, and plug
in the console. Everything is automatically in focus and
ready to use. The layout inside the dome when assembled
is illustrated in Figure 1.
Figure 1. Northern Stars Planetarium general layout of
projectors, cables, carpets, and dome.
THE CONTROL CONSOLE
The control console was designed to sit in the center
of the dome. It was built to serve several functions.
First, as already mentioned, it housed a number of the
special effects projectors. Second, it served as a base
for the star projector and a westerly directed slide
projector. Third, it was to be the mechanism that
controlled every projector in the planetarium. The north
facing side has a dark Plexiglas plate set at a slight
angle. This plate was drilled to hold toggle switches,
dimmers, and 12 volt D.C. controls. This panel would
control the remote slide projectors and all the special
effects projectors. The layout of the console control
panel is illustrated in Figure 2. The size and shape of
the console can be seen in Figure 3. The south side of
the console contains an access door and several
projection window ports. On the east and west sides of
the console are some switched AC outlets and three 12
volt D.C. outlets. On
Figure 2. The control console created for the Northern
Stars Planetarium.
the north face, below the Plexiglas control panel is
on non-switchable A.C. outlet, two ammeters to measure
the current drawn on the two incoming cords, a projection
port for the aurora projector, an hours of use dial, and
one momentary button. The momentary button fires the
strobe that is flush mounted on the top surface of the
console. The switch is mounted here so that it can be
fired with the knee, freeing the hands for other things
during those dramatic transitions!
Figure 3. The dimensions, given in inches, of the control
console of the Northern Stars Planetarium. Total weight:
65 lbs.
EKTAGRAPHIC IIIe SLIDE PROJECTORS & DIMMERS
We picked Kodak Ektagraphic IIIe slide projectors
because they offered us features that we needed in a
slide projector. They had to be able to forward, reverse,
focus, and dim remotely. We also did not want auto-focus.
Auto-focus uses an internal light to maintain focus. This
is not a problem for a general slide show, but in a very
dark star theater there is a ghostly rectangular glow
which is not wanted in the planetarium.
For dimmers we chose KBGE Series Solid State A.C.
Variable Voltage Control Assemblies rated at 15 amperes.
These were used in conjunction with a 250 K Potentiometer
with a Linear Taper (Part #53C3-250K). Both of these
parts are available at Midwest Associates of Rockford,
Illinois, (815) 962-8036. The voltage assembly sold for
under $25.00 and the potentiometers were less than $10.00
each. I have used these dimmers steadily since 1987, and
not one has yet failed.
One more suggestion. Use the lower wattage EXY bulbs
in the Ektagraphics. They are slightly more expensive
than the higher watt standards, but they last years. In a
portable planetarium the added wattage is not needed as
the greatest projection distance is only sixteen
feet.
THE DOME
We also made some slight modifications to the dome.
First, we still use the old square utility type fans. I
understand that Learning Technologies has a new fan
system that works very well; however, I have modified my
system using the "old type" fans and I am completely
satisfied with it's performance. I use two fans, one
blowing through the other. They are velcroed together. I
found that one fan was not sufficient to maintain a tight
dome with the fan blowing in the low position, while I
found the medium setting to be too loud. The answer was
to use two fans. Two fans, blowing on low, will hold the
dome up with a minimum of wrinkles, while maintaining a
lower noise level than a single fan set at medium.
Another nice feature about this method is that if a fan
should fail, you have a back-up immediately available. A
second fan can be purchased for under $40.00 from
Grainger® (part #4C418). Of course, you do have to
attach your own snaps. If you do use two fans, it's
important to remember to always keep them both set to the
same setting; we have discovered that having one set on
low and one set on medium is very hard on the motors. We
had a motor burn out that way, so keep them set at the
same setting and you shouldn't have any problems.
We have also attached Velcro tabs on each seam along
the spring-line (the horizon) on the inside of the dome.
This allows the placement of glow-in-the-dark cardinal
points and other attachments.
CARE & THE COLD
Our dome is eight years old and we have had nearly
100,000 students through it in those years. It is
certainly showing some hard wear after all those knees
and feet crawling through it. To prolong it's life as
long as possible we have done a few things, and will do a
few things differently when we get our next dome. First,
we have the kids take their shoes off before entering.
This rule cuts down grime from shoes and boots, and it
also makes everyone more comfortable sitting on the floor
for an hour. This is not a hard and fast rule, sometimes
it is dropped if the day's schedule is really tight or if
the principal tells me there will be a fire drill or if
it is a junior high school with a lot of traffic through
the gym--I don't want any $100.00 sneakers stolen.
To repair pin holes we only use the little patches
that Learning Tech. provides for quick fixes. We have
found that children will pick patches off the dome nearly
as quickly as we can put them on. For a more permanent
fix Sue Reynolds of Onondaga-Cortland-Madison B.O.C.E.S.
Planetarium in Syracuse, New York suggested fabric paint.
This works great. It is quite durable, although mixing an
appropriate color of gray is a bit of a trick. For seams
that open, we use the standby--duct tape. Duct tape is
the perfect color, but it does have to be replaced every
month or so, it slowly peels up around the edges.
One last note on dome wear and tear, we have noticed
that the entrance tube and where kids sit takes the most
abuse. Beyond the regular pin holes, we have found that
the fabric often gets stiff and separates into it's
composite layers. We have developed a theory that this is
probably due, in large part, to the oils from hands. We
have started to experiment with different cleaning fluids
for cleaning these surfaces. We are hoping that this will
remove some oils and keep the material more supple.
Projectors also require additional care above and
beyond the regular cleanings and maintenance when
traveling. Our planetarium is seldom left overnight in a
school, so it spends its nights (real nights that is)
packed in the back of my van. The van is parked in a
barn, but in Maine in January it's not uncommon for it to
drop to -15° F. This past winter our coldest night
was -35°; in my van, in the barn, it was slightly
warmer, about -25°. Have you ever turned on a slide
projector that is twenty degrees below zero? I'll tell
you, nothing good happens. The fan doesn't turn, but the
lamp will come on; however, that would be a bad move. If
the lamp doesn't shatter, a lens or mirror just might! So
what do you do? You need those projectors to be up and
running at 8:45. That's why you must have a vehicle with
a good heater to at least get those projectors warmed up
above freezing. When you get them inside the school, open
up the cases you have them in and let the air at them.
Once they are in place and plugged in, turn the
projector's fans on, but do not turn on the lamps. The
slower you bring them up to temperature the easier it
will be on the lenses and lamps inside. Condensation is
also a problem with cold lenses, again air flow seems to
solve the problem as quickly as just about anything. Be
very careful if you should decide to wipe the
condensation off.
The dome's blower fans sometimes need to be warmed up
this way too. As soon as you get them inside, turn them
on and just let them run without the load of the dome.
Also unroll the dome and let it lie there exposed to the
warmth of the room. The dome's fabric gets very stiff
when it is extremely cold.
Cassette tape decks also like to be warmed up when
cold. I usually plug mine in and open the carriage gate
(where you put the cassette). Then I press fast-forward
and let it run without a tape in the machine. I press
fast-forward because that is the only setting that my
Bose Acoustic Wave® will run on without a cassette in
the carriage. If this procedure is not done when the
machine is cold, it runs slowly.
Laser pointers like to be warmed up in a hip pocket. I
think they just like to be next to my wallet to remind me
how much they cost! Actually, it's the batteries that
need warming, but it's easier to just slide the whole
pointer in a pocket.
The video projector is the most sensitive to cold. It
just doesn't like it. In reality, I don't think it is so
much the cold as the condensation that forms when it hits
the warm moist air inside the school. When that happens,
it might not run all day. For that reason, when it is
cold outside, the video equipment must come in for the
night. It's my only equipment that doesn't live in the
van during the winter.
CONCLUSION: REMEMBER WHAT'S REALLY IMPORTANT
At a glance, it might seem that I rely too heavily on
my equipment. Where's the personal touch? Ultimately, no
matter what hardware you may have, the most important
piece of equipment you carry with you is you. This may
sound a bit cliché, but it's true. If you've seen
planetarium shows at different planetariums across the
country, you know that not all shows are equal; further
more, you've probably also noticed that having the most
advanced equipment doesn't necessarily give you the best
productions. In the right hands, all those fancy gadgets
can really dance; in the wrong hands, they just add
confusion. Don't add things to your set-up unless you're
comfortable with their appropriate use. Ultimately, in a
Starlab or any small planetarium, you are the show. All
those fancy do-dads can only do their job well if you can
do your job well.
When we advertise our business, Northern Stars
Planetarium, we don't try to sell the fact that we have
lots of projectors or technology. We don't advertise our
product as a Starlab either. I don't sell Starlabs and I
don't let the fact that I use a Starlab be my drawing
card. Don't get me wrong, I love my Starlab, it's a great
piece of equipment, but when it comes to my business I
sell me, my expertise, and my programs. I want my clients
to want me to return to their school, not just any
portable planetarium. Remember, the most important
hardware you have is you.
