Is that its real colour?

[Guest peepshow]

I've seen many pictures of very colourful looking DSO's, both here and on other forums.

 

Take the ever popular M31.......... the bread and butter shot of the sky.

 

The latest I have seen of M31 had subs taken in lum, red, green, blue,, Ha. Then Integrated for many hours.

Then processed using 4 apps such as Pixinsight, PS, CS5 etc.

 

After all that how does one know what M31 should really look like and are other shots taken in a much simpler way, not  colour appearance true?

 

When does bread and butter look like bread and butter or like  burnt toast, if one were out in space to see it?  

[Brantuk]

Well.... yes..... and no..... The processed images combine the wavelengths of light given off by an object to produce a composite picture. As far as the visible spectrum is concerned then yes that's what colour it is.

 

However - the human eye can't see Ha wavelengths because it can't do long exposures like a camera, and the camera only see's those wavelengths when they are reflected or emitted - same for ultra violet and other wavelengths outside the visible spectrum - so no it's not that colour and not what we would see close up - especially as colour is defined as what we can see..

 

However, bread, butter, and burnt toast, are within the visible spectrum so they are that colour. But if you were out in space you'd have trouble seeing burnt toast in my kitchen, and you'd probably struggle with seeing the house as well lol

[+Graham]

If thy are taken in RGB then the colours will be pretty true as these are the primary colours that all others come from.

Obviously when you start messing with the balance of the RGB in a processing suit then the colours will change.

I personally think that is the beauty of it as each individual person will produce  a slightly different picture, one that suits their personal tastes and imagination.

[Guest peepshow]

Then the pictures are becoming an art, not a science if they are manipulated to suite individual taste.

 

So I guess that NASA's M31 pics are nearest the truth. 

 

Anything other is just toast.

 

Thanks for replies guys.

[Guest Kheldar]

Then the pictures are becoming an art, not a science if they are manipulated to suite individual taste.

 

So I guess that NASA's M31 pics are nearest the truth. 

 

Anything other is just toast.

 

Thanks for replies guys.

 

Unless you can pop over there and have a look for yourself, you're never going to get the "right" answer in post processing, even with RGB.

 

Taking it one step further, narrow band processing allows actual science (not art) to be done - by adjusting the colour balance of the channels you can study the breakdown of the gasses in further detail. The didn't invent the Hubble palette just to make pretty pictures

As to NASA's images ... just as open to interpretation as the rest of them ...

 

Simple answer is they are all right ... just as equally as they are all wrong

Edited September 24, 2013 by Kheldar

[xanthic]

All photographic processing is done to bring out the detail that was desired, whether developing, dodging and burning in a darkroom or pushing curves in Photoshop.

 

If images are created using light outside of the visible spectrum, then that needs to be mapped into a colour range that we can see.

[Sheila]

Narrowband picks up the different gases in the nebula etc.  You can map the 'correct' colours for the gases by using their emmission/absorption spectra.

Unfortunately Ha would dominate as red and one of the other gases is also red, so it would make for a rather confusing image.  Hubble images

were actually done for research into the behaviour of the gas clouds, but make rather pretty pictures too.

[philjay]

To quote our sage Doc, (Mick) when asking a similar question "Its cheating" when presented with similar answers

Someone had to post this on this thread :-)

[Doc]

 

I wondered who would quote that.

 

And guess what you were top off the list Phil 

[+Ibbo]

To quote our sage Doc, (Mick) when asking a similar question "Its cheating" when presented with similar answers

Someone had to post this on this thread :-)

I bet they said that to Lippershey 

they certainly did to Galileo

Edited September 25, 2013 by Ibbo

[Perkil8r]

Simple answer is no. Partly due to the fact our atmosphere will tint everything blue to some degree or other due to the light being bounced off all the atoms in it etc, hence why the sky appears blue above the clouds*. Also the speed things are moving towards and away from us will have an effect on the wavelength, stuff moving towards us shifts toward blue, away towards red. The closest you will get to "True" colour is when some clown such as myself shoots OSC (one shot colour) with a DSLR or similar. The colour still alters slightly and we nearly all adjust the saturation in some way or other at some stage.

 

*Blue wavelengths are shortest and get scattered about more.

[Sheila]

Simple answer is no. Partly due to the fact our atmosphere will tint everything blue to some degree or other due to the light being bounced off all the atoms in it etc, hence why the sky appears blue above the clouds*. Also the speed things are moving towards and away from us will have an effect on the wavelength, stuff moving towards us shifts toward blue, away towards red. The closest you will get to "True" colour is when some clown such as myself shoots OSC (one shot colour) with a DSLR or similar. The colour still alters slightly and we nearly all adjust the saturation in some way or other at some stage.

 

*Blue wavelengths are shortest and get scattered about more.

would think Mike that the true colour was meant if you had a spaceship out there looking at it, what would you see

[Perkil8r]

would think Mike that the true colour was meant if you had a spaceship out there looking at it, what would you see

 

Yes, which is what I'm saying, from Earth no camera will ever show the true colour