galaxy and nebula colours

[Petehog72]

Hey all, may seem like a daft question but just need to clarify, when looking through the scope galaxies and nebula present as a black and white smudge, does the colours we see on pics come from post production or filters, thanks in advance,   pete

[rockystar]

It comes from long exposures (mostly). We can't see colour when looking through a telescope because the cones in the eye don't get activated properly. You can get a bit of colour from some of the brighter objects, but not much

[Petehog72]

Thanks for the reply, we are just wetting our feet in astrophotography so very much look forward to experimenting

[Marky1973]

Check out this thread if you haven't already

And the book, "Turn Left at Orion" will help you find some great targets and give you an idea of what you can expect to see in various instruments!

[pblackwell]

Hi Pete, Just to add, I found that a good Nebula filter can help when viewing Nebula. Sometimes I'm able to almost get a slight green tone. Remember to use 'averted vision' technique when viewing them.

Paul

[Nyctimene]

Not much colour up there, if you are going visual on DSO's. M 42 will show a greenish hue, and some of the planetary nebulae are distinctively green (Saturn nebula = NGC 7009) or green-blue/ turquoise (Cat's Eye nebula = NGC 6543), which is seen best when using a O III or UHC filter. Galaxies always will appear grey/white. If you are looking for red colours, try some Carbon stars, e.g. R Leporis, south of Orion.

Stephan

[pblackwell]

2 hours ago, Nyctimene said:

Not much colour up there, if you are going visual on DSO's. M 42 will show a greenish hue, and some of the planetary nebulae are distinctively green (Saturn nebula = NGC 7009) or green-blue/ turquoise (Cat's Eye nebula = NGC 6543), which is seen best when using a O III or UHC filter. Galaxies always will appear grey/white. If you are looking for red colours, try some Carbon stars, e.g. R Leporis, south of Orion.

Stephan

Or the Garnet star, and Albireo double star (great contrasting colours) Beautiful they are!

[Daz69]

The Garnet star was one of my first observations, and it was/is beautiful. Much more red than Betelgeuse IMO.  

[ollypenrice]

There are two kinds of colour image, colour mapped  narrowband and natural broadband RGB. Colour mapped images use 'false colour' and map one particular gas to one particular colour as a geology map might map a particular kind of rock to a particular colour. The colour is artificial but instructive. A well made braodband RGB image should show what we would see if we had big enough eyes. It turns out that if you combine three images, one in red, one in green and one in blue, you get a very good approximation of what the human eye will normally see. Daytime digital cameras and smartpohes etc work this way. They shoot the three colours simultaneously on adjacent pictures. Astrophotographers may use three filters in turn but the principle is the same.

Star colour is easy to see, especially if you look for it consciously. Even in a large scope, though, I see very little nebular colour myself, except when using an OIII filter which passes green light. It's quite a person-by-person thing, I think.

Olly

[paraman]

On 2/1/2017 at 16:32, pblackwell said:

Hi Pete, Just to add, I found that a good Nebula filter can help when viewing Nebula. Sometimes I'm able to almost get a slight green tone. Remember to use 'averted vision' technique when viewing them.

Paul

Just to add to this, our eyes cones are the source of colour vision but at night we revert to rods as this is primarily dark adapted and is much more acutely tuned to respond to movement.  There are proportionately far more rods on the periphery hence why averted vision is often successful when viewing dim objects.

[LukeSkywatcher]

As brilliant as the human eye is by design (can distinguish minute subtleties between about 13 million shades of colour in fully lit conditions), Its pretty damn useless at night.