Nature of astrophysics (5) - astronomy, quantitative only?

[Nereid]

Before Galileo started looking at the sky through his telescope, the only permanent things in the sky that were not points were the Sun, the Moon, and the Milky Way (unless you could see the Magellanic Clouds!). And the points - stars - did not change their relative positions, the Moon always looked the same, as did the Milky Way (and the Magellanic Clouds). Sometimes the Sun got spots on it, and the full Moon got dim, and even turned a beautiful reddish-orange (but otherwise looked the same); very rarely (only during a total eclipse of the Sun) a lovely pearly glow could be seen around the Sun (or was it the Moon?). Some of the stars did seem to change a bit in brightness, and one or two got so faint they disappeared for a while (but they always came back). Occasionally there was a comet, and very rarely a 'guest star'.

Except, of course, for the five planets - Mercury, Venus, Mars, Jupiter, and Saturn; they wandered around the sky, but in a way that seemed to fit a pattern.

The pinnacle of pre-telescopic astronomy (at least in Europe) was Tycho Brahe's star catalogue and meticulous sets of records of the positions of the planets. Not surprisingly, they are wholly quantitative, i.e. 'just' sets of numbers, no 'a little bit to the west of', or 'close to'. In fact, Tycho even estimated what we'd today call the uncertainty, or error, in his quantitative data; however, his estimates turned out, upon later analysis, to have been somewhat under-estimates (among other things, there was an unrecognised systematic error in his star catalogue; systematic errors are the bane of an astronomer's life!).

Once telescopes were used to observe the sky, quite a few objects were seen to be more than just points, so observational astronomy began to include some drawings, or paintings, qualitative data in other words (and not just maps of the Moon!). In fact, there really was no way to record what we today call 'extended objects' except by drawing them (well, 'word pictures' were possible, but a rather poor alternative).

That is until photography began to be used in astronomy. Then astronomical observations became a lot less subjective, and quantitative analyses of extended objects - galaxies (as we call them today), nebulae (of various kinds) - began to become common. However, quantitative analyses of this kind are often quite tedious, especially if you have to do all the calculations by hand!

Starting around the 1960s two revolutions began to hit observational astronomy, CCDs and computers; fast forward to the 21st century, and everything is now quantitative.

When you look at an Astronomy Picture of the Day which comes from the Hubble, Swift, Herschel, Fermi, XMM-Newton, Planck, one of the Very Large Telescopes in Chile, one of the Kecks (in Hawaii), SDSS, or even an amateur's backyard telescope ... what looks like a picture, or image, or photograph, isn't. What it is is a representation of rather a lot of data, and nearly always involves considerable processing of the outputs from whatever instruments or detectors were used (done by computers, of course). You could take the very same data, process it in a different way, and produce an image which looks quite different! We are all probably used to 'false colour images', but you'd be surprised at how differently the very same data can be made to appear ... yet its status as an astronomical observation is exactly the same.

[Goldminer]

what looks like a picture, or image, or photograph, isn't. What it is is a representation of rather a lot of data, and nearly always involves considerable processing of the outputs from whatever instruments or detectors were used

Yup, and sometimes, in small print the picture says "artist's impression!" Of course one should Never ever question the "considerable processing of the outputs," should they??

[Nereid]

Of course one should Never ever question the "considerable processing of the outputs," should they??

Of course you should, as often as extensively as you wish!

In fact, many facilities have a clear policy of releasing not only the processed data, but also the raw data; MAST is a good place to start learning about what's available, in case you - or any other reader - are interested.

[Goldminer]

The following quotes are taken from: Guidelines for Contributing High-Level Science Products to the Multimission Archive at STScI Here at Mast

Output produced from theoretical models closely related to the MAST data and not generally available through another permanent archive.

Thoroughly tested and well-documented specialized analysis software relevant to the HLSP, Java applets, and other image display software. (MAST will archive such software but will not accept responsibility for maintaining it).

[Italics inserted by Goldminer]

Just like I said, or implied; Any "analysis" is a higher level abstraction and depends upon the viewpoint and biases of the writer/implementer. Raw data can be skewed too. One has to be ever vigilant. So, now I am a Vigilante. Scrutiny is no vice. As the original poster of many threads on Thunderbolts Forum, you manage to dodge the really detrimental points to your theme, made by several members of the forum, and continue discussion of ideas benign to your agenda, for which you supply loads of links. "Noise proves nothing. Often a hen who has merely laid an egg cackles as if she laid an asteroid."(Samuel L. Clemens) And, I might add: Often the egg is infertile.

"We are all probably used to 'false colour images', but you'd be surprised at how differently the very same data can be made to appear ... yet its status as an astronomical observation is exactly the same."

"(done by computers, of course)"

Implying what; that computers are some how unbiased? Halton Arp, for example, has analyzed the data from his catalogs, and revealed all sorts of relationships, contrary to consensus astronomers, who use similar analysis without criticism for their own pet theories.

No one is under obligation to use the criteria of the theory under analysis in their own theory, to contrast their own theory with it. And yet those who debate the alternative theory try to defame it because the alternative theory didn't use their pet definitions, assumptions etc.


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[Nereid]

Just like I said, or implied; Any "analysis" is a higher level abstraction and depends upon the viewpoint and biases of the writer/implementer. Raw data can be skewed too. One has to be ever vigilant. So, now I am a Vigilante.

Good.

May I ask how you will go about doing that?

As the original poster of many threads on Thunderbolts Forum, you manage to dodge the really detrimental points to your theme, made by several members of the forum

Such as in the JREF forum bashing of Anthony Peratt's work..., 'Gravitational lensing, galaxies' - EU explanation?, 'Microlensing' observations - EU explanations? and Quasars... threads?

Implying what; that computers are some how unbiased? Halton Arp, for example, has analyzed the data from his catalogs, and revealed all sorts of relationships, contrary to consensus astronomers, who use similar analysis without criticism for their own pet theories.

Are you saying that Arp did not use computers in his analyses? that the data in "his catalogs" were compiled without the use of computers in any shape or form?

As you can no doubt see, I'm struggling to understand what you points are, Goldminer.

[Goldminer]

I am saying that they both use computers and they both proceed along their own beliefs. One is singled out for criticism, and the other is taken as the Gawdawful truth. Keep "struggling to understand" and "straining to see," someday you really will.