The images you see on the dome of the Planetarium are a result of picture slides, halogen lamps and optical lenses in various “opto-mechanical” projectors; on the main unit, for example, 31 projectors are just for showing the stars. “These images must overlap by 10 per cent, only then will they merge and seem like a continuous picture,” said Biju, the operator.
How is this done? Manually. “We have to change the slides in the projectors for each show, align individual projectors and play the visuals one by one to see that there is no flaw,” he said. It takes between 250 and 300 slides per show. And this is just to change a show.
There are two ways the planetarium has acquired its shows - either by buying them from Goto’s Indian branch or making them from scratch. This, like the building of Rome, is not the work of a day. “It takes a month to make a 30 minute show - preparing the storyboard, deciding the visuals, sending them to be developed as slides, recording the audio and so on,” said Biju. “Everything needs to be perfectly timed - how long does it takes to read a sentence in English and to convey the same info in Malayalam.”
The timing is important since it tells the operators when to change visuals and how long to keep one. The audio is recorded separately and has to be matched with the visuals appearing on the dome. “Obviously, the audio can’t be talking about Leo when we’re still showing Cancer,” said Biju.
And that is why each show on at the sky theatre is kept for around four months at a time. However, from keeping the same show for months on end, the planetarium will soon be able to have several up at a time. For, these long-drawn processes and the outdated equipment - the slide projectors, open reel tape deck and the main computer whose floppy drives condemn it to a forgotten era - will soon give way to a tilted dome and new projectors enabling IMAX-equivalent shows.
The old GM-II star field projector, expected to play its swan song sometime in the next two months, will be displayed at the upcoming Astronomy Gallery at KSSTM. “This instrument would have comfortably worked for another two decades, I think. The only fact rendering it ‘obsolete’ is that it is not digital,” said founder-director Ramachandran Nair.