Tactile Star Wheel for Visually Impaired Observers
Masashi YAJIMA, Toshimitsu YAMAGUCHI, and Tetsuya WATANABE
(University of Niigata, Niigata, Japan)
Keywords: Astronomy Education, Blind People, Star Wheel, Tactile Symbol
E-mail: email@example.com, firstname.lastname@example.org
A star wheel is a tool whereby observers can view stars and constellations that are in the sky
at certain dates and times simply by rotating the wheel against the holder. Star wheels are
both inexpensive and simple to use, making them popular as an educational material.
The Space Exploration Experience (SEE) Project has made tactile star wheels for blind and
visually impaired people . However, the design found on the SEE Web site seems to have a
few problems: the stars on the wheel are too big and some of them are too close together to be
correctly perceived as the figures of constellations; day lines are too few and not neatly
arranged; all Braille labels on the wheel are aligned in the same direction, so some labels
appear in the oval window at an awkward angle; and regular (i.e., not Braille) letters are not
included, which means that sighted persons cannot understand or explain the wheel to their
blind or visually impaired companions.
Therefore, we decided to create a new tactile star wheel specifically geared to the tactile
perception of blind persons and the visual appeal for sighted persons.
2 Related Work
Many kinds of tactile astronomy education materials have been created around the world.
“Touch the Universe: A NASA Braille Book of Astronomy,” “Touch the Sun,” and
“Getting a Feel for Lunar Craters”  are tactile books which includes embossed or
transparent raised planets, stars, and nebulae. 3D planet models have been produced such as
“tactile moon”. Recently 3D printers make it easier to produce tactile planet models ,.
Tactile planetariums are large domes or spheres with tactile “stars” on the inside of the domes
. Creating tactile planetariums is hard work as they cannot be made automatically. Tactile
star charts have many good points of other educational materials: they are handy, easier to
produce, and inexpensive as tactile books and interactive as 3D models and tactile
3 Tactile Star Wheel
In our proposed tactile star wheel, stars, constellation lines, labels, and markers are made
tangible by using microcapsule paper. The wheel is 1.5 times bigger than regular star wheels
so as to make the figures of constellations discernible by touch (Fig. 1).
3.1 Stars and Constellation Lines
We found in a former work that a 2-mm difference in diameter makes differently sized circles
perfectly distinguishable . Therefore, we express stars with three kinds of dots according to
their magnitude: minus to 1 magnitude stars with 4-mm outline circles, 2 magnitude stars with
4-mm black circles, and 3 to 5 magnitude stars with 2-mm circles (Fig. 2).
Tactile symbols smaller than 1 cm are hard to discern , so we magnified most of the
constellations to larger than 1 cm. This makes our wheel, with a diameter of 459 mm,
approximately 1.5 times larger than regular star wheels.
Constellation lines need to be narrow enough to avoid misidentification as dots when they are
very short. We set the width of these lines to 0.7 mm.
Too many tangible objects make it hard to distinguish one object from another, so we limited
the number of constellations to fifteen of the more famous and popular ones.
3.2 Date and Time Markers
Date and time markers are expressed as tangible lines. To determine the optimum number of
tactile date markers for lining up the desired date and time easily, we performed an
experiment in which fifteen blindfolded sighted participants were asked to line up the
designated date and time with wheels featuring three different tactile date marker conditions:
every day, every two days, and every five days . There were three main findings:
1. Lining up the date and time was faster under the every-two-days and every-five-days
marker conditions than under the every-day condition.
2. The dates with tactile markers were lined up faster under the every-five-days marker
condition than under the every-two-days condition.
3. Lining up errors were less than one day under all conditions.
Based on these results, we drew the tactile date markers around the wheel every five days
3.3 Regular Text and Constellation Art
In general, tactile figures alone are difficult to understand, so for the visually impaired, having
a sighted person explain them is vital. To facilitate such explanation, we added regular text
and constellation art to the wheel and the holder. These are printed in blue so that they do not
rise up when heated.
3.4 Tactile Constellation Cards
Larger constellation figures than those in the tactile star wheel help facilitate an understanding
of the exact composition of the constellations and stars included in them, so we also prepared
tactile constellation cards printed on large (DIN A4 size) sheets (Fig. 4).
Fig. 1. Proposed tactile star wheel. Fig. 2. Stars and constellation lines.
Fig. 3. Date and time markers. Fig. 4. Tactile constellation card.
4 Demonstration and Dissemination
We demonstrated our tactile star wheel at the 2012 and 2013 “Sight World” events for blind
and visually impaired persons which gathered about 5,000 people every year. It has also been
introduced in lectures at schools for the blind. Up to now, 60 or more tactile star wheels have
been presented to blind people and individuals who are engaged in teaching or assisting blind
people. They have given us a lot of positive feedback, including:
“We have heard a lot about stars and constellations, but this is the first time to touch them.”
“I had thought that constellations and stars have certain concrete figures such as a dipper or
five-pointed star. For the first time, I realized that all stars are round.”
“I wish I had had this when I was a student.”
5 Future Plans
Microcapsule paper wears down easily and is not suitable for long-term use. We are therefore
planning on using a more endurable tactile material such as UV-curable resin. We may also
change the way paper is printed at the factory to help increase its durability.
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