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Sunday, 12 April 2009


Hi, Ctein!
So — if we're still around in six years I can depend on you to notify me of this camera going on line? (It'll be high time, Ctein.)
Happy Easter!

This is very cool, indeed, Ctein.

I didn't know the quote was attributed to Haldane, and I certainly can't say what he meant by this, but here's how I always understood it: it's not a matter of who's allowed to vote, as you seem to imply, it's just that no matter how many people vote that the earth is flat, it won't change the fact that it isn't.

Sorry, Haldane is right, you simply misunderstood him.

First of all, anybody can cast his "vote" in science, [s]he need not be a 'qualified individual' - one needs only be intelligent enough to follow the logic and methodology. That's the beauty of science, it is not restricted to the chosen few.

Counter to democracy, and that is what Haldane meant, science is not about number of votes in favour of a proposition. Since science is concerned with the truth and nothing but the truth, crawling slowly towards it tiny step by tiny step, it does not matter if most people think a claim to be right or wrong.

Even if most 'qualified individuals', that is, scientist in the same branch, disagree with the results of an experiment or with a proposition it might still be right. Thus science is not a democracy.

And here is Mike's 1.3 megapixel camera complete with 180 degree wide field of view:


The Canada of sciences, eh - we'll show you... :)

Only kidding some of my best friends are Canadian.

One thing perhaps of surprise to some readers here is that they are going to make that giant focal plane out of 189 fairly small 4kx4k CCDs. The truth is that although chips for digital cameras have been moving ahead in leaps and bounds, for us it's all in the wrong direction - built in Bayer matrix, smaller pixels, lower dark current at room temperature (who cares when we have liquid nitrogen) etc. Astronomical detectors are advancing apace in the infrared but in the optical it can be best described as a dribble. Most of these wide-field arrays use the same 2kx4k chips they did ten years ago. About the only thing that has improved is the IR sensitivity which now goes about 100nm further.

Of course the reason we can't have larger chips is the same reason your common or garden medium-format digital back costs so much - the fabrication yield drops like a stone for larger physical sizes so the price goes through the roof. Worse still the demand is low which doesn't drive toward the economies of scale with mass-production.

If anybody is about to suggest the "crop camera" solution (shorter focal length) think again - an f/1.2 reflective optical system is hard enough. Unlike photography we do care about (physical) aperture since it controls sensitivity to point sources (stars) which is more important for many of us than sensitivity to extended sources (nebulae, the night sky, etc.) that does scale with f-ratio (well actually solid angle subtended by each pixel if you want to get technical) in the same way as (daytime) photography.

Not only is Astronomy more democratic but I've heard that hobby astronomers are employed by professionals to help gather data. I believe IOTA, the International Occultation Timing Association is one example of this cooperation.

Actually, the FOV is 3° in photographic terms - it's 10 square degrees. That's roughly equivalent to the diagonal FOV of an 800mm lens on a 35mm format camera.

I can't say I've heard that quotation before, but I have to agree with the two previous commenters that it's meant to imply that scientific truth is not a matter of popularity. Which is the whole beauty of the thing.

Dear Renaud, Dierk and Justin,

The scientific process *is* a democratic one. A new 'fact' (theory, model, whathaveyou) is proposed by a few people. A much, much larger body of qualified people, the scientific body politic, evaluate the claims. They argue, discuss, investigate, etc. Some people agree some don't. Eventually, a supermajority decide they agree (or don't) and the proposal becomes accepted (or rejected) scientific 'fact.'

There is no mechanism in this that guarantees objective truth. What makes it of extreme philosophical interest is that it works extremely well at determining useful information about the world. It arrives at a 'correct answer' (don't ask for those words to be defined too closely).

These two statements, while hypothetically true, do not reflect what actually happens:

"Even if most 'qualified individuals', that is, scientist in the same branch, disagree with the results of an experiment or with a proposition it might still be right."

"no matter how many people vote that the earth is flat, it won't change the fact that it isn't."

In the abstract, they're valid. In the real world of scientific process, you will not have the majority of scientists converge on a "flat earth" solution the majority of the time. It's just not the way it ends up working.

It would be plausible to say that there's no sensible reason why science should be a democracy, why that should not produce erroneous results. That's a fascinating and unanswered question. But that's about the why of it. The what of it is that it is a democracy and it manages to consistently converge on useful answers.

In fact it's a question that's interested me since my philosophy of science class at Caltech.

But after 40 years, I still don't know the answer to the why. I just know it successfully works that way.

pax / Ctein

Dear Micheal,

Thanks for catching my error! Ummm 10 square degrees, 10 degrees square... they're the same thing, right? [ahem]

Shoulda caught my goof just from the illustration, which shows the (half-degree) moon superimposed on the array.

pax / Ctein

Ctein, science is not a democracy, and even as an oversimplification it's simply wrong.

First, you are putting the cart before the horse (there's a really geeky joke there I'll spare everyone). "A democracy" implies that the decision on what is correct is done by force of opinion. That researchers see a given theory as the right one _because_ most other researchers have decided that it is. It implies that you have freedom to decide what is correct.

But you don't. Changing consensus comes about as a reaction to changing facts. It's an effect, not a cause. To make an analogy to real democracy, you'd have a majority of voters voting for a candidate because they have been informed beforehand that he is the winner. That's not democracy.

Second, even disregarding the above, science is not a democracy and it is not egalitarian. Your track record does matter, and it matters a lot. Somebody who's written the standard books in their field and with a Nobel price or Fields medal under their belt (I'm thinking of Eric Kandel and Lars Hörmander here for no particular reason) is going to have vastly more clout in any discussion than some mediocre third-rank jobbing researcher like myself. Somebody without the basic credentials like a PhD (think of it as a driver's license for research) is only rarely going to have any voice at all, and for good reason. Call it a meritocracy if you will, or any of several uglier names, but a democracy it is not.

(there's a really geeky joke there I'll spare everyone)

please, tell us the really geeky joke.

Dear Janne,

We do not agree. Democracies are not necessarily egalitarian. Votes are often weighted by criteria.

The value of evidence presented for or against a proposal is heavily weighted by the credentials of the presenter. That may sway votes. Or not. The votes still are what count. A Nobel laureate may fervently champion a position, but unless they convince their peers, they do not change the accepted wisdom. And should they not relinquish their position after failing to convince, they'll lose status and crediblity.

The voting is certainly a cumulative and evolving process. With each new debate and presentation of data or interpretation, some more scientists become convinced pro or con (or switch sides). It can take many decades. At some point the vote count clearly, overwhelmingly favors one side or the other. At that point, the prevailing side is considered established knowledge. Until that happens, no matter how much you may be convinced your side is correct, it is not considered 'proven.'

I don't think I have the cart before the horse, I think you do. There is no external nonhuman thing you would call 'science.' There is an observable universe. The patterns and systematic observations we glean from it, placed in a certain kind of cognitive framework, are science. The means by which that knowledge gets acquired and placed is the scientific method, and the mechanism is the scientific process. And that process requires getting the bulk of the body politic to sign onto a proposal, and that is a democratic one.

FYI, hardly any scientists talk about 'truth;' it's really not the currency we deal in. Useful and verifiable facts? Sure. But TRUTH? Nahhhh.

pax / Ctein

Ctein, my analogy above still stands - the validity of a theory over time is not determined by its popularity; its popularity over time is determined by its validity. "democracy" does not enter into it.

BTW, I did not use "truth" anywhere in my post; I know better than to do so. You are sure you want to state that I did?

Ctein, I urge to read up a bit on scientific method, starting, say, with Plato and Aristotle through Hume and Berkeley up to Sir Karl Popper. Upon rethinking, since Popper did all the work for us, you could just look into The Logic of Scientific Discovery and Objective Knowledge.

To add a bit to that.

- Just because individual humans are unable to find the truth does not entail there is no truth.
- Even if all humans over all time are unable to fully graps the truth it does not entail there is no truth.
- Just because many highly specialised branches of science are strangely complex, non-intuitive, and use a special language most people didn't understand the basics of in primary school [mathematics], does not entail that only 'qualified' people have a say. As was already pointed out by the astronomy example.
- It may be a counter-intuitive fact that scientific progress does not rely on voting, but that does not change the fact. It took even the scientific community - the 'qualified people' - more than half a century to accept Charles Darwin's theories, which doesn't change a iota about the truth of his ideas. Other examples include hereditary genetics [Mendel] and plate tectonics.
- The 'voting' as you describe it is only about acceptance [hey, I got an allusion to Kübler-Ross in] - not of the facts but of the one[s] founding them.
- Regardless of how many 'qualified people' have accepted a scientific finding for regardless how long, if only one man or woman finds conclusive proof that the accepted truth is false, it is false. Again, the number of people accepting the new proof doesn't matter at all [as doesn't any meaningful interpretation of 'qualified'].
- The reason scientists proper, that is those dabbling in physics, chemistry and parts of biology, do not talk about truth has nothing to do with them looking for it; truth is a matter for philosophers. Usually scientists have so narrow a field they intuitively know that their findings are only tiny part of the truth - nevertheless, 'facts' is just another word for truth, and scientist know that as well.

Let's not forget that this started out by a rather idiosyncratic interpretation of a Haldane quote. Or are we now into a serious epistemological discussion?

Can I point this thing at my neighbors swimming pool? :)

Yes, of course you can point it at your neighbour's swimming pool. You just have to arrange for an orbiting mirror to be in the right place at the right time - which may be cheaper than buying the camera...

Hi Ctein,

A very big tip o’ the hat for the kind mention. The LSST is a gift to all of us low budget astrophotographers. For those who can’t wait six years, I have been aware for quite awhile now of the ability to rent telescope time. Here are a few sites to check out:


I am sure that there are others. I cannot vouch for any of them so let the buyer beware.

As an aside, your LL video on dye transfer print-making was wonderful. A must have for anyone who bought one of your prints.


In the next couple years, the new Wide-Field Planetary Camera will be installed as part of the last Hubble upgrade, too. Hopefully.

Late to the party...
Since this is about astro-photography, I want to plug my "neighbor" who has some great info about getting started in amateur astro-photography:

Reading the posts above on science and Democracy, I need to put in my two cents...
In science, EXPERIMENT IS KING. (I robbed the next line from a prof. that Ctein might have had at CalTech) Science hinges on the idea that any two people in the universe can setup the same experiment with the same conditions and they had better get the same results! (Observations can count as experiment).

It is in the interpretation of these experiments that a form of "democracy" comes into being. It often takes years for the scientific community to come to a consensus on the "why" of an experiment.

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