Recreating the Night Sky!

Birth Centenary of the Planetarium

 

“When we look out into space, we are looking into our own origins, because we are truly children of the stars.”

– Brian Cox

[The motivation to write this article has come about not only because this year marks the centenary of the advent of the planetarium as a powerful educational tool for learning astronomy and related sciences, but also because of the expected completion and commissioning of a state-of-the-art planetarium, the first of its kind outside Japan, in my home city of Mysore next year.]

 

Inside a modern planetarium

A planetarium is a theatre built primarily for presenting educational and entertaining shows about astronomy and the night sky. Planetariums of today employ sophisticated computerised digital processing and display techniques to recreate the night sky and astronomical events in stunning detail.

 

The Beginnings

When ancient cave dwellers summoned enough courage at night to come out of their hidings and step out into the open, with the firmament over their heads, what they saw was the amazing, though chaotic, sight of a dazzling night sky, which the light polluted city-dwelling modern man often yearns to see in its pristine glory.  Initially, they looked at the night sky as something to be feared, for they knew not what to make of it.  But the fear gradually yielded to some sort of curiosity, marking the birth of astronomy, the oldest science known to humankind. Over the past few millennia, observational astronomy has become as much of a hobby among the inquisitive as a science in pursuit of the unknown among those who have made it a profession.                                                                                  

One of the earliest discoveries was of a handful of night sky objects called planets, which behaved differently from the innumerable stars.  Stars seemed fixed in their positions in the sky, whereas the positions of planets changed.  The role of the earth’s rotation about its own axis on the observed motions of the night sky objects was an equally significant discovery. Since then, the chaotic looking night sky has lost much of its sheen of mystery through systematic observations, leading to a complete picture of our solar system against the background of stars, and of the stars themselves and other objects as part of our Milky Way galaxy. Initially, the observations were only visual, aided by some simple measuring instruments. In this context, the reader may like to refer to one of my blog articles here for a detailed account of the wonders of the night sky visible to the naked eye. 

The invention of the telescope and its use for the exploration of the night sky by Galileo (1564 – 1642) opened up a new frontier in observational astronomy. The subsequent application of spectroscopic and photometric techniques in conjunction with telescopic observations led to an understanding of the composition of stellar objects, their physical properties, and a complete description of their motions, eventually leading to a definitive understanding of our stellar neighborhood, of a picture of galaxies beyond our own, of clusters and super clusters of such galaxies far beyond, and of the vast expanse of the universe itself around us right from its birth in the Big Bang. 

Limitations and Impediments

A totally dark night sky, without any light pollution, affords the best theatre for observational astronomy, but nature has its own say in the matter.   Here are some hurdles to overcome:

· Cloudy and hazy skies introduce an uncontrollable impediment even in the best of locations.

· Weather and climatic conditions introduce additional constraints.

· Urban and semi-urban locations, with significant light pollution, are the least conducive.

· A bright moon can interfere with observations quite severely.

· The number of viewing days/hours in the year with an acceptable level of suitability is severely limited even in good locations.

[Amateur astronomers sometimes use the ‘bortle scale’, which is a good guide to the observing conditions at a given site and its level of light pollution. There are nine levels to the Bortle scale, with Class 9 being the most extreme of light pollution, something that most dwellers in megacities experience most of the time.]

· For all practical purposes, observational astronomy is a night time endeavor, bringing in many logistic and other constraints, especially for providing direct educational experience, particularly for girls in many conservative societies.

· Portability of telescopes and support equipment to the observation site can pose a problem at times, while larger, permanently mounted telescopes are inflexibly linked to the observational conditions available at the site.

Below is a very instructive picture posted in Quora Digest by Eva Silvertant, a professional observer, showing how greatly the night sky visibility changes with atmospheric conditions. Over a period of four decades since I moved in to my present home in Mysore in south India, I have experienced the whole gamut of changes shown here, from right to left of course, as visible even in the best of times overhead from my home! 

Birth of the Planetarium

Initially, astronomy education and the pursuit of amateur astronomy depended mostly on detailed maps of the night sky and other printed material, with very few visual aids, barring the telescope.  A major breakthrough came with the invention of the modern projector planetarium exactly a hundred years ago. It was an electromechanical planetarium projector (see picture below) designed principally by Walther Bauersfeld and built by the German optical firm Carl Zeiss of Jena in 1923 for the new Deutsches Museum in Munich, and unsurprisingly named ‘Mark I’. The first official public showing was at this museum on 21 October 1923.  It generated all the necessary movements of the stars and planets inside the huge optical projector, and projected images of the night sky onto the white plaster lining of a 16 m hemispherical concrete dome.

In view of the historic importance of this pathbreaking innovation, the following detailed description of it from the ‘howstuffworks’ website is relevant here:                  

           A concave metal sphere known as a star ball used 31 lenses to show images of 4,500 stars on the dome. Seven additional projectors attached to the ball created images of the sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn. The movement of these projectors replicated the movement of the solar bodies relative to the stars. The illumination of the images came from a bright electric lamp in the centre of the ball, surrounded by the 31 lenses. Behind each lens was mounted a disk called a star plate which served as a photographic slide. Light from the lamp passed through holes in the plate, each of which represented a star. With each lens focusing light on the dome through holes in its star plate the 31projectors together produced an image of the entire sky.

          However, the Munich Planetarium had some limitations. The view of the planetarium was confined to Munich and other places that have the same northern latitude, which means the planetarium could only show stars that rose above the horizon at the latitude of Munich. But with the technical advancements the improved versions of Munich planetariums could show the sky from any place on Earth and at any time up to 26,000 years into the past or future. In the improved planetariums, which use two large star balls and a planet projector in between, stars appear similar from any place in the solar system but the planets do not. This is because the solar system is much smaller than the distances to the stars. 

 

     The success of the Zeiss projectors led to the establishment of thousands of planetariums in the 20th century. In the United States, the first Zeiss projectors were installed in the 1930s at the Adler Planetarium in Chicago, the Hayden Planetarium in New York City, the Fels Planetarium at the Franklin Institute Science Museum in Philadelphia, and the Griffith Observatory in Los Angeles.

Here is a picture of the Zeiss Planetarium Model II, an improved version of the one described above, in operation at Barmen, Germany in 1926, one of the earliest ones to come up anywhere in the world:

In the 1941 picture below, visitors to the Hayden Planetarium at the American Museum of Natural History in New York are seen with the Museum’s first Zeiss ‘two star-balls projector’, and one of the earliest in USA:

A vastly improved version of the electromechanical Zeiss planetarium (Model Skymaster ZKP4 LED), with the two large star balls and the planet projector in between, is in wide use all over the world. Shown below is a picture of this planetarium projector installed at the Tamilnadu Science and Technology Centre, Chennai, India. It uses LED light sources and fiber optics.  The two star-balls, one for the northern celestial hemisphere and the other for the southern celestial hemisphere, driven together by a single motor, ensure that the star field can be produced synchronously, everywhere on the dome, encompassing the whole of the night sky.

The latest version in the evolutionary history of the celebrated Carl Zeiss planetarium projectors is the UNIVERSARIUM Mark IX LED (see picture below), designed for large domes and multimedia star theatres, for all types of domes.

Why a Planetarium?

The advantages of a planetarium as an educational tool are manifold. Here are some, pertinent to conventional electromechanical projector type planetariums: 

· The night sky can be recreated in a closed space very realistically.

· The night sky corresponding to any geographical location at any time, for any calendar day, far into the past or future, can be recreated accurately.

· Motions of the objects of the solar system can be shown precisely with respect to the background of stars and other stellar objects.

· The apparent motions and appearances of night sky objects can be controlled in a variety of ways, resulting in an immersive experience.

· The motion of the Sun against the backdrop of stars can be shown, something that is virtually impossible otherwise.

The modern state-of-the-art computerized digital display-based planetariums outperform the conventional ones in a big way.  Here are a few of their superior features:

· Ability to take the viewer beyond the Milky Way, to galaxies and extra-galactic phenomena/events such as supernovae, dark matter, etc.

· The appearance of the night sky and stellar processes within it can be recreated as viewed from anywhere in our solar neighborhood, or even beyond.

· The whole evolutionary process within the universe, from the Big Bang onwards, can be simulated in consonance with current theoretical models.

· Phenomena such as eclipses and transits for any set of solar system objects, including solar and lunar eclipses, can be predicted and simulated with high precision.

· Because of their advanced video and audio capabilities they can be used in any area of education and entertainment.

· The more recent LED projectors are distinctly superior to conventional video projectors in depicting a wide variety of stellar phenomena.

Planetariums for Education

The role of planetariums in science education, going beyond just astronomy education, is best described in the following statements excerpted from the website of The International Planetarium Society:

The star projectors that show the night sky itself are among the most durable, versatile, and cost-effective of educational tools.

Planetariums are the world's astronomy classrooms and theaters of public science education that have served perhaps a billion people during the past century. The world's 3000 planetariums are found in schools, colleges and universities, and museums and science centers in all 50 US states and in over 100 countries around the world.

In a time when quality science education is more important than ever, a scientifically literate public is an essential part of the progress of any country. Planetariums around the world both inspire and educate people of all ages about our surroundings - the Earth itself and our place in the Universe - and they are often a place in which young people become enthused to follow a scientific career. Many of today's leading scientists chose their careers because they were captivated by the experience of a planetarium visit.

Planetariums also were used to train early astronauts in celestial navigation techniques. By showing the fascinating discoveries in astronomy and space exploration, planetariums are a major tool in increasing science literacy. This dissemination of knowledge distinguishes our time from the Middle Ages, when knowledge was restricted to an elite few.

Also, a one-page summary of the “Value of Education in the Planetarium” in the same website, highlighting other ways in which planetariums can inspire prospective STEM (Science, Technology, Engineering and Mathematics) students and influence the community as a whole, is also instructive.

Modern Planetariums

Pioneered by Carl Zeiss, the early planetariums were all essentially analog devices, with an optical projection technique manipulated ingeniously by electromechanical controls. The advent of computers of ever-increasing power and sophistication, especially computer graphics, opened up exciting new possibilities, ushering an era of hybrid planetariums.  They employ the best of both technologies – the superb quality of the star fields created by conventional opto-mechanical planetarium projectors, and the versatility provided by computer graphic visualization techniques to produce a range of special effects like simulation of views of the sky from any desired location in space, flying through space at varying speeds, rendering images from digital data bases created by telescopes and spacecrafts, providing views of astronomical events in real time, etc. 

The hemispherical domes whose interior surfaces served as the screen for the planetarium projectors, were passive ones even in the early hybrid devices.  The directly projected images, using multiple projectors each with its own computer control system, were supplemented by computer graphic images projected in a variety of ways, including use of fisheye lenses, superimposed on them.

One of the most advanced graphic techniques is the digital dome in which the entire curved screen is made of tiny LED (light emitting diode) elements, which can be controlled individually to light up in different colors and brightness as on a TV screen.  The resulting videos are remarkably vivid, much like the experience in IMax theatres, with 3D effects also possible. They represent the latest in planetariums today, achieving resolutions as high as 16K, in tilted domes designed for better interior layout and viewer comfort. They can also be supplemented by conventional projectors, operating in a hybrid mode.

Some Famous Planetariums

Most major towns and cities in the world today are served by planetariums of some type or other, offering valuable educational content to students and the general public. Many of the older ones with conventional electromechanical projectors have undergone a major upgrade to more sophisticated hybrid type projection systems, suitable for numerous academic disciplines besides astronomy and related sciences.  They are also being used to provide educational as well as general entertainment.

Here are brief descriptions of just a few of the better-known contemporary planetariums in different parts of the world:

The Adler Planetarium: This is part of a public museum in Chicago, USA, dedicated to astronomy and astrophysics. Located on the northeastern tip of Northerly Island on Lake Michigan, and founded as far back as 1930 by local businessman Max Adler, the Adler Planetarium (see picture below) was the first planetarium in the United States. Since inception it has undergone a series of expansions and technical upgradations, and is now one of the best in the world. Its broad mission is to inspire exploration and understanding of the universe. Surrounded by several thematic sculptures, its stunningly attractive building has been declared a National Historic Landmark.

Birla Planetarium: The Birla Planetarium in Kolkata (see picture below) is one of the oldest in India and the largest in Asia, as also the second largest in the world.  Its 23 m diameter dome has a seating capacity of 688. It reopened to the public on 18 July 2017, after closing down for over two years for major renovations work. The technical upgrade equipment was delivered and installed by Carl Zeiss AG. The renovated planetarium has a ZEISS Hybrid system, with the STARMASTER, an optical-mechanical planetarium projector, working in sync with a dome video display system.  It offers to the public and students more than 100 astronomical projects dealing with various facts of astronomy, astrophysics, space science as well as myths concerning stars and planets. 

Zeiss Major Planetarium:  The Zeiss Major Planetarium in Berlin (in the part of the city belonging to GDR, formerly East Germany) is one of the largest modern stellar theatres in Europe. The dome of the main hall, with a diameter of 23 m and a seating capacity of 307, is equipped with a Universarium IX planetarium projector from Carl Zeiss AG, the inventors of the world’s first modern planetarium a hundred years ago. The planetarium dome is shown in the picture below, with the inset showing the planetarium’s old Zeiss projector that was decommissioned in 2014. The facility is also used for frequent music concerts and as a venue for the annual for the Berlin International Film Festival. 

Nagoya City Planetarium: The largest planetarium in the world is in Nagoya City, Japan and is part of the larger Nagoya City Science Museum.  With a dome diameter of 35 m, it can seat 350. First opened in 1962, it was shut down in 2010 for a major reconstruction. The new planetarium (see picture below) is equipped with a Zeiss Universarium Model IX Starball Projector, and later further upgraded to a digital DYNAVISION LED dome system developed by the Konica Minolta company in Japan. 

Hayden Planetarium: The historic and iconic Hayden Planetarium, part of the Rose Center for Earth and Space (see picture below), which is itself a part of the American Museum of Natural History in New York, is considered to be the most famous and most visited planetarium in the world.  Its current director is the world-famous astrophysicist, innovator and science communicator, Neil deGrasse Tyson, who has stated that he owed many of his accomplishments to the motivation he derived from visiting a planetarium in his formative years.

The upper half of the huge 27 meter diameter dome (appearing to float inside a glass cube) seen in the picture constitutes the Hayden Planetarium, a 429-seat Space Theater, which features a custom-made Zeiss Mark IX Star Projector and a Digital Dome Projection System to display a hyper realistic view of the planets, star clusters, nebulae, and galaxies, using an accurate 3D map of the observable universe based on millions of astronomical observations.  It opened in 2000 along with the Rose Center for Earth and Space, and remains an enduring beacon of astrophysical education and research, as was its predecessor, which opened in 1935. Its Digital Universe Atlas is a 3D map of the cosmos maintained by a team of Museum scientists and visualization experts, in collaboration with colleagues from organizations such as NASA and ESA. It also provides the foundation for the Museum’s Space Shows, which are screened in the Space Theater.  

On 19 August 2017, just two days before I viewed the great total solar eclipse of that year near Nashville, TN, I had the wonderful opportunity to spend half a day at the Hayden planetarium viewing the numerous exhibits, exploring the 13.7-billion-year evolutionary history of the universe on its spiral ‘cosmic pathway’, and ending with a spectacular show in the Space Theatre. 

Yokohama Planetarium:  On 24 March 2022, KONICA MINOLTA PLANETARIA YOKOHAMA, the fifth directly operated Konica Minolta Planetarium, opened in the newly constructed Yokohama Gate Tower in Yokohama City, Japan. The planetarium (see picture below, and at the beginning of this article) is equipped with the DYNAVISION-LED dome system, released by the Konica Minolta Planetarium in July 2019.  A much higher brightness and a wider color gamut than conventional projection systems are its most impressive features. These are combined with their latest digital planetarium solution, Media Globe Σ SE, to create an amazingly photorealistic experience of the starry sky and the universe. With the combination of DYNAVISION-LED and Media Globe Σ SE, it is now possible to reproduce the beauty of the vivid blue sky and ocean, the red brightening of a gorgeous sunset, and the twinkling shiny stars. The depth of the image serves to increase the sense of immersion and makes it more realistic than ever before. 

Shanghai Planetarium: Opened in 2021 in Pudong, Shanghai, this is truly an architectural marvel besides being the world's largest planetarium in terms of building scale (see picture below). Its dome covers an area of 38,000 square meters. The planetarium, designed by New York City based Ennead Architects, serves as an educational and entertainment site for visitors and is part of the much larger Shanghai Science and Technology Museum. With no straight lines or right angles, the building was designed to reflect the shapes, movement and geometry of the universe. The foundational design concept of the museum was to “abstractly embody within the architecture some of the fundamental laws of astrophysics, which are the rule in space.” 

Jawaharlal Nehru Planetarium, Bangalore:  The Jawaharlal Nehru Planetarium (JNP) is administered by the Bangalore Association for Science Education (BASE). BASE is basically devoted to science popularisation and non-formal science education. Located in the heart of the megacity of Bangalore, which is also the nearest to my home city, JNP (see picture below) attracts over 300,000 visitors annually, a majority of them being students. The planetarium is equipped with a large 15 m dome and a state-of-the-art hybrid projection system commissioned in 2017 after a major upgradation from its previous version. The JNP organizes several interesting programmes aimed at school students and the general public. They include sky-theatre shows every day, monthly star gazing, science club activities, science movies, viewing of astronomical events, etc. One of its notable ongoing outreach activities is a three-year long week-end programme titled REAP (Research Education Advancement Programme) for undergraduate students. Equally noteworthy are its indigenously developed sky theatre shows, with commentary in Kannada, the predominant language of the state. 

Mysore COSMOS Planetarium

As indicated at the beginning, my motivation for writing this article is not only the centenary this year of the invention of the first (Carl Zeiss) projector planetarium, but also the imminent prospect of a state-of-the-art planetarium soon coming up in my home city of Mysore, India.

This cutting-edge planetarium is being built in Mysore as part of the Cosmology Education and Research Training Centre (COSMOS) project, which is funded by MPLAD (Members of Parliament Local Area Development Scheme) funds from the Indian union finance minister Nirmala Sitharaman, the Department of Science and Technology, and the Department of Atomic Energy, Government of India.

The Indian Institute of Astrophysics (IIA), Bangalore, has initiated a significant landmark in the development of astronomy in the country by placing an order for the world’s first commercial DYNAVISION LED Dome Planetarium outside Japan with the Konika Minolta Inc Consortium, Japan, which includes RSA Cosmos in France and Orbit Animate in India. The project is being overseen by the Principal Scientific Advisor to the Government of India and is managed by IIA, an autonomous institution under the Department of Science and Technology.  Furthermore, Kothari and Associates in Kolkata has been awarded a contract for the architectural work of the campus and building, with the building plans currently being finalised and the process for selecting a civil contractor underway. The planetarium is set to be completed next year.

Here is a picture taken at the time of signing of the customer contract between IIA (represented by its director, on the left) and the representative of Konika Minolta on the right:

Most planetariums worldwide rely on a hybrid projector system to cast images and movies onto a passive dome. However, the planetarium system to be installed in Mysore will be unique since it does not need a conventional projector at all. Instead, the dome will be made of panels of millions of self-luminous LED elements that are directly controlled by a highly sophisticated computer graphics system. The planetarium show will be displayed through the LED elements on the dome itself, offering much better contrast, with 8K resolution, and eliminating issues typically encountered with conventional projection systems.

There are currently only two installations of such a system in the world, both in Japan, and both operated by Konica Minolta for public viewing. This planetarium in Mysuru will be the first LED dome planetarium in the world supplied by the vendor to an independent customer. Here is a picture showing the world’s first such undertaking: 

The Mysore COSMOS planetarium is expected to be much like the Yokohama and Nagoya planetarium systems outlined above. It will have a 15 m diameter 15⁰ tilted dome, with a unidirectional seating capacity of 150.  Besides the planetarium, a permanent astronomy and space exhibition, and other related activities, are also being planned.

The planetarium will be located in the campus of the University of Mysore (UoM) at the foot of Chamundi Hill and is being executed through a Memorandum of Understanding (MoU) between the IIA and the UoM.

To prepare for the planetarium’s opening, various astronomy outreach and education activities have been underway in Mysore and surrounding areas for the past year. These activities include talks on astronomy for college and school students, astronomy data analysis workshops, educational events for rural schools and telescope sessions for the public. These activities will be further intensified in the coming months leading up to the planetarium’s completion.

At the time of this writing, no technical details about the planetarium and its housing and support facilities were available.  I hope to revert to them in a future article sometime after the planetarium starts functioning.

Concluding Remarks

I thought of writing this article only after I fortuitously realized that this year marked the centenary of one of the great inventions of modern times, from the land well-known for such trailblazing achievements, and within it, one of the legendary pioneers in electro-optical instrumentation, the Carl Zeiss company. I also didn’t want to wait until 21 October, the actual date of the centenary, so as to contribute to the advance publicity being created of its significance. The fact that it coincides with the commencement of work on India’s own world-class planetarium in my home town, with my own ‘pre-launch’ association with it in a small way as a member of the Education and Public Outreach Committee, is a pleasant coincidence. The two events together merit this broad review of a century of innovations aimed at recreating the night sky in all its glory, sweeping away all bounds of space and time.

Tailpiece

Remarkably, almost everybody, including ministers, vice chancellors and high-profile professors, some even professing physics, twist the word ‘planetarium’ to pronounce and spell it as ‘planetorium’, rhyming with ‘auditorium’.  I plead for a moratorium on this if not the crematorium!  Incidentally, there is no such word in any English language dictionary, a fact cheekily ignored or overlooked, even by those who use auto-correcting features of the word processers they use regularly.  I am at a loss to understand how this can happen. Some linguist or ethnologist may have the answer.