for the astronomers- colour?

[Tash]

doing a 2 week summer course in astronomy, and of course being the 'ex'-artist i am i choose to write a 2000 word essay on 'colour and astronomy'- what do you write about? so far i've got the whole temperature thing and it affecting the colour of the stars and stuff.anything else?

[pianolearner]

doing a 2 week summer course in astronomy, and of course being the 'ex'-artist i am i choose to write a 2000 word essay on 'colour and astronomy'- what do you write about? so far i've got the whole temperature thing and it affecting the colour of the stars and stuff.anything else?

What a coincidence. I happen to be watching a documentary on Super massive BLACK holes. You could write about Galaxies and RED shift or Blue shift which is an indication of speed and distance. (Doppler effect)

https://en.wikipedia.org/wiki/Red-shift

https://en.wikipedia.org/wiki/Blueshift

Forgot to add, talk about studying chemical composition of distant objects using spectroscopy as well

https://en.wikipedia.org/wiki/Spectroscopy

[timothy42b]

Can't talk about color without talking about human vision, cones and rods, three types of color receptors (four in some people) and the fact that every child is taught the WRONG primary colors in school.  That should be good for at least 2 billion words. 

[prometheus]

Write about the spectrum of stars. You can see what elements the stars are made off looking at the spectrum. Of course thanks to the red-shifting we know that the universe is expanding. The movement of the star can also be observed thanks to red-shifting (and in this case blue-shifting too).

https://webcast.berkeley.edu/courses/archive.php?seriesid=1906978149

[pianolearner]

Tash,

In reference to colour shifting you can talk about how planet hunters use this when searching for planets. They observe a distant star and watch to see if the light from the star is shifted over time due to an orbiting planet exerting a gravitational tug.

“To detect the planets, the astronomers looked for a wobble in their parent star's motion, detectable as a shift in the star's spectra. A tell-tale oscillation in the frequency of certain bright lines in the star's spectra reveals the presence of an unseen companion. “

Paul Butler and Geoff Marcy are the worlds leading discoverers with this method.

https://planetquest.jpl.nasa.gov/science/finding_planets.cfm

NB: Some astronomers dispute the validity of some discoveries made this way.

Also, astronomers use non-visible colour, or colour that is beyond the frequencies our eyes can detect such as Ultra-violet and Infrared.

https://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/importance.html


In regard to what timothy said about primary colours. Because light is an additive mixing process the primary colours are different to those used in painting which is a subtractive (I think) mixing process. The primary colours in light are RED, GREEN, BLUE. If you look closely at your TV screen you will see thousands of RED,GREEN,BLUE dots. Each group of three form a Pixel (picture element) and produce different colours depending on the amount of illumination. The eye is extremely sensitive to Green and less sensitive to Blue, so to produce white they are mixed in the following ratios known as the Trichromatic ratio.

1T lumen White = 0.59T Green + 0.3T Red + 0.11T Blue

[thalbergmad]

Don't forget to write a few words about Edwin Hubble.

He worked out all that red shift stuff if i remember correctly.

[Tash]

ok apparently the question has to do with false colour...now i'm not sure...will ask the lecturer tomorrow...but yes will keep all that in mind cos it's interesting woo i want a telescope right now!

[prometheus]

False colour?

We are talking about everything in the electromagnetic spectrum. So any photon stuff. Visible light is just a small part of this. There are telescopes for every kind of electromagnetic radiation. This all works the same.

[pianolearner]

ok apparently the question has to do with false colour...now i'm not sure...will ask the lecturer tomorrow...but yes will keep all that in mind cos it's interesting woo i want a telescope right now!

False colour is a way of enhancing pictures to increase detail. This is especially useful when observing objects using wavelengths that are out of our visible range such as Infrared and Ultraviolet. The advantage of using different wavelengths is it allows astronomers to see objects that may otherwise be obscured by clouds of gas or dust, or if they want to look at objects that would destroy an ordinary telescope, such as the Sun. I believe they use X-ray mapping for this.

A number of images are taken through various filters and a composite image is then created. Most colour images we see of distant galaxies and planets are created this way, quite often they are computer enhanced. Do you need 2000 words to explain this???

[Tash]

ok well asked the actual lecturer today who said it's just about stars and stuff so back to what we were originally talking about will continue looking at that thanks all!