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The first planetarium projector was unveiled 100 years ago

planetarium100.org

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Re: The first planetarium projector was unveiled 100 years ago

#21

Earlier quoted context omitted.

It sound's a bit odd this is even notable. This is the minimum standard for any new construction commercial/institutional building according to recent building codes in Ontario, and probably many other jurisdictions. Maybe it's unusual for these building code standards to actually be enforced without special exemptions where the writer lives?

I was in a developing country where such things are rarely if ever enforced by law. Though, because many HVAC systems are imported, they automatically satisfy reasonable standards. Our company had ethics enough to try and enforce such reasonable standards without any external pressure.

> Though, because many HVAC systems are imported, they automatically satisfy reasonable standards.

Not necessarily, because it's trivial to turn down HVAC systems to a smaller, code violating, number of air exchanges per hour.

Re: The first planetarium projector was unveiled 100 years ago

#22

I love planetariums but it seems like most of the shows now are just films projects spherical screen. I’d really love to see one using an old-school star projector but it seems like they’re very hard to find now.

The word I love is "star ball". My local museum has one of these. They're apparently difficult for upkeep, since they've been produced such low volume. There's only a handful of specialists who travel around the country servicing them.

There's actually a Wikipedia page [0] (no doubt lovingly curated by beautiful nerds) that has a long list of planetariums with Zeiss star projectors.

But there's still the problem of finding shows where they are actually used...

0: https://en.wikipedia.org/wiki/Zeiss_projector#List_of_planet...

Re: The first planetarium projector was unveiled 100 years ago

#24
post #13

Earlier quoted context omitted.

BH Photo has a nice page on planetarium projection systems. They are eye-wateringly expensive. https://www.bhphotovideo.com/explora/photography/features/pl... ?

All I see on the Zeiss website for price is a "contact" button. How expensive are we talking about? :)

From the 2019 BH Photo article whose link I posted above:

"Cost has long been a factor in the acquisition of an OM projector. The Zeiss Model II cost $75,000 in 1926—more than $1 million in today’s dollars. Modern OM projectors can cost well over $2 million."

A 2011 Sky and Telescope article about Boston's Planetarium says, "Costing $2 million, the Zeiss Starmaster installed at Boston's Charles Hayden Planetarium uses fiber optics and its lens-covered 30-inch ball to project up to 9,100 stars."

https://skyandtelescope.org/astronomy-news/bostons-planetari...

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