Will TMT be the biggest building on the island?

You see this claim bandied about routinely in newspaper comment sections and Facebook, It has several variations, from biggest, tallest, to largest, to most area. This has been repeated since the beginning of the controversy and continues to the present as a protester staple.

TMT Rendering
An overhead view of the proposed Thirty Meter Telescope, credit TMT Observatory Corporation

This particular myth is easily disproved as there are any number of buildings on the island that are much larger in several respects. All you need is some elementary school math.

Is it proposed to be the biggest building on the island? yes, it is.

Brons Keola Kobayashi, Facebook comment

My apologies about the Imperial units used here, most of the folks who might read this are familiar with feet and acres in place of meters and hectares. I tend to do my math in metric, then convert the answer if needed for the audience.

I will use one simple example to check this one… The Kona Costco building, not even the largest building on the island, just one I can find good numbers for and many people are very familiar with. The Kona Costco has 156,000 square feet under the roof, this is 3.58 acres, never mind the parking lots that multiply this area.

The Costco is roughly 700×220 feet in size, while the TMT dome is 216 feet in diameter. The entire TMT structure would sit neatly within the floor space of Costco… Twice.

In terms of volume it is a bit different… To calculate the volume of Costco I will multiply by 32ft, (my estimated height of the roof from a photo) to get 4.99 million cubic feet of volume. In comparison the TMT dome is 66m in diameter, and 180 feet high. Modeling this as a hemisphere on a cylinder you arrive at a volume of 5.27 million cubic feet, more volume than the Costco, but still comparable. I do not have any good numbers to estimate the additional volume of the support structure.

That is Costco, there are a dozen buildings of around the same size on the island, all of the big box stores… Home Depot, Target, Lowes, KMart, Walmart, etc. I believe that the single largest building on the island is the Prince Kuhio Plaza, many times larger yet with 510,000 square feet of space.

All 13 telescopes can fit inside of the proposed one so taking away 4 is really like adding 9 instead of another 13

Brons Keola Kobayashi, Facebook comment

This volume thing leads to another claim, that the TMT is bigger than all of the existing telescopes combined, that they could “all fit inside”. Again easily disproved… Subaru alone comes in at 2 million cubic feet, each Keck dome is about a million, so is the JCMT… Done. No need to even add in the large Gemini dome to top the size of TMT, much less CFHT, IRTF, etc., etc.

How about tallest structure on the island? That honor will continue to be held by wind turbines of the island. The Vestas V47 wind turbines at Upolu with their 155ft diameter blades and a hub height of 180ft are much taller than TMT. The wind turbines of Tawhiri Power at Ka Lae are even taller… These GE turbines are 215 feet to the hub, with a total height of 330 feet to the upper rotor tip.

A variation on this one is that TMT is as big as a football stadium. Again this is just wrong, the TMT could fit on a standard football field, much less the stadium that surrounds it.

When you really start to look at the size you realize that the TMT telescope enclosure is really not that much larger than the existing Subaru telescope building, which is 140ft tall. this is thanks to the very efficient design of the TMT that packs a lot into a surprisingly small building. Placing the telescope down on the lower plateau will make the TMT less obtrusive than many of the existing large telescopes on the mountain.

Result: Completely False

Author: Andrew

An electrical engineer, amateur astronomer, and diver, living and working on Mauna Kea, Hawai'i.

6 thoughts on “Will TMT be the biggest building on the island?”

  1. However, it is true that the TMT will be the tallest building on the island. It will be ten meters taller than Bayshore Towers in Hilo.

    1. Incorrect, read again… There are at least a dozen structures on the island far higher than TMT, far more visually impacting and sited in what I believe is a more sacred landscape than the summit of Mauna Kea… Ka Lae.

        1. Umm… Wind turbine, 220ft to the hub, over 300ft tall at the upper blade tip, far more visually and aesthetically obtrusive than an observatory, it moves.

          1. Ah, so you are being deceptive in two different ways.

            A wind turbine is not a building.

            And a wind turbine does not take up nearly the same footprint as the TMT building will.

            1. Who is being deceptive? A wind turbine is a very large, visually obtrusive structure. The turbines located at Ka Lae are nearly twice as tall as the proposed TMT dome. For the sake of this argument deciding a wind turbine does not count is being knowingly dishonest. If you are going to shade the meaning of words then a telescope is not a building either.

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