Colour Descriptions Books to Actual

[Craig79]

Maybe a strange question, definitely a newbie question. 

I'm using the Sky at Night magazine to give me some targets to aim for and I'm using a Skywatcher Heritage 130p with standard 25mm and 10mm Skywatcher lenses. When the text says I'm looking for 'a faint coloured glow' or 'carbon red' how vivid should this be down the lens. For example tonight I tried to find IC5146 the Cocoon Nebula. I worked from M39 and saw a yellow/orange star roughly in right place is that the faint glow? Googling other peoples images show the light more diffuse and smudged but they were taken with better kit than mine.

Thanks. 

[Mr niall]

They're all grey, everything. One of the difficulties of visual observing is that it doesn't match what cameras pick up on long exposures. With the exception of double stars and planets pretty much everything you see with your own eyes will be in black and white - I use a 127 maksutov and have never seen any colour in any nebulae. I think you'll struggle to pick out the cocoon at all with your kit (I know I can't, but that doesn't mean much! I'm not very good and observe in the light pollution heaven of the 'burbs!)

Actually just checked - it's a tough target in all but the darkest of skies. You may be right on it but it's just too faint to see. 

[John]

Colour detection in visual observing is very subtle I find. Younger eyes seem to detect the tints more easily and distinctly than my older eye can but even so the vast majority of deep sky objects appear as shades of grey visually.

 

[scarp15]

I would definitely start out with a copy of 'Turn Left at Orion' - look on Amazon and refer to the accompanying drawings for a realistic expectation and for realistic subjects when starting out and going forward, using a small scope and / or binoculars. Selectively there is colour, such as potentially and subtly in the Orion Nebula for example and some planetary nebulae, stars, planets etc, yet concerning most DSO's, they will be observed as grey, do not expect too much in visual terms - texture and contrast are more prevalent features.  

[Tim]

It is a great question Craig, and one which comes up regularly.

There are precious few deep sky objects that do give you any colour, and those that do are among the brighter objects in the sky except stars and planets.

Some planetary nebula exhibit a bluish colour. The only other object I have seen to give any colour at all, even in a big 24" scope, is M42, the great Orion nebula, which can display as a very pale bluish green, almost like a transparent duck egg colour.

To allow any colour to come through, allow your eye to relax on to the target and observe it steadily for as long as is comfortable. I find that even red coloured stars, of which there are many, don't become obvious to me unless I really look at the view properly, and they gradually appear.

The best way to enjoy colour views though is to observe double stars that vary in colour between gold and blue. The contrast makes the colours all the more vivid. A great starting point, which can still be seen at the moment, is Albeiro at the bottom of Cygnus.

Another easy to find pair is Almach in Andromeda. While you are there hop over to nearby Mirach which is a stunning golden star, and see if you can spot the galaxy fuzz which is nearby, known as Mirach's Ghost.

You might also enjoy finding Herschell's Garnet star.

Hope that helps

Tim

[ollypenrice]

For me, too, colour is only available in stars and the small, highly concentrated planetary nebulae like the Blue Snowball - which is very blue. That's in large apertures, 20 and 14 inch, though my eyesight is on the wrong side of indifferent.

On an astronomy course, once, one task we were set was to estimate ten stars by colour, naked eye, and place them on a blue to red continuum. I found, like others on the course, that this was perfectly possible once you set your mind to it. I ended up with two stars inverted near the middle of the spectrum but the rest were in the text book order.

Olly

[JOC]

I liked the blue snowball too, it is def. blue.  I found the way to bring out the colour of the double stars like Albeiro if you can't see it is just to nudge them slightly off focus - then they become sparkly and the colours really stand out.

[ronin]

Just about everything will be a "grey" . There is usually insufficent light from the object to allow the colour vision cones to fire. Add in that everyone wants to get dark adapted and their night vision operating but your night vision is mono = black+white+grey. So in mono what colour is say yellow ? Many people find that viewing Saturn, and I suspect Jupiter, is better at dusk as the colours from Saturn are better resolved by the colour vision of the eye which are still active.

To detect colour you will need to collect sufficent light and it will help to have an idea of the colour expected.

The eye also uses contrast to a significant extent so a nebula filter that passes Hb and OIII could be useful. Knisley recommends a nebula filter but not an OIII filter, likely therefore that the main emision is in the Hb. Images of the Cocoon apper red so unsure if Ha is useful owing to the eye response. Also the Red may be false colouring. Wiki says the Cocoon is both emission and reflection.

A dark location will be useful, maybe essential. LED lights are bright and although they direct light better (less pollution) you are in the pool or layer of bright light. I would seruiously question if anyone could attain reasonable dark adaption.

If trying for carbon stars they are dim and usually very deep red, can be very much at the edge of the visible spectrum for people, so "seeing" them can be not so easy, it is easy to just not register their presence. Then again many people do not register M31 until it is pointed out.

If you are having trouble picking out the faint and dim ones then do not take a 6 year old along with you. They just make it very apparent that older eyes are not as good.

[Craig79]

Thanks,for the,repkies everyone - its good to know its not me missing colours! 

[N3ptune]

I wish to disagree with everything being gray, not the cocoon obviously but other things, I see plenty of colors visually. 

- The kelvin scale for the stars, some are orange, some are yellow, some are beige, some are white, some are bluish.

- Orion's nebula is greenish without a filter (it was green even with 130mm aperture)

- Blue snowball is blue (more then bluish)

- Cat's eye nebula is like a green laser pointer (it's in my logs)

- Saturn's nebula emerald green (it's in my logs)

- Some star clusters have orange stars inside of them.

- The main stars of the pleiades are bluish.

- Rigel is bluish, Betelgeuse is deep orange.

- Carbon stars are yellow, orange, some of them are truly red like blood (in averted vision), here are my logs: 56 DRA Deep rich red color, 64 DRA Super red, 67 LYR Deep orange, 76 LYR a Ruby gem <-- it's true (; they are incredible.

If this can help..

 

 

 

[Dave In Vermont]

It would all be shades of white to black (invisible) if it weren't for our atmosphere. When filtered through the air and soot and water-vapour around us & our eyes, refraction wouldn't occur. And it's the combination of Kelvin and refraction that allows us to see the colours in the stars and all. As well as make certain objects brighter, too, when you factor in human physiology & optic-nerves.

It's rather complex.

evaD

[25585]

Black & white photos can be a better guide for shapes & contrasts. 

Having started way back with photos from Mt Palomar etc, later colour photos of the same objects seemed too unreal. 

Finding a DSO is fun, but what you find can be disappointing. 

Too many coffee table books & magazines. 

If you find Azelfafage, then pi2 Cyg in a straight line, the Cocoon Nebula is roughly along that line of sight, the same gap again. 

[Stub Mandrel]

Even here the pleiades and teh nebulaosity looks blueish.

Your 'carbon red' probably refers to something like the garnet star which should be an obvious orangy red.

Compare Betelgeuse and Rigel at opposite corners of Orion, even I can see one is blue and one is orange!

I can't say I have seen colour any any other nebulosity, but I haven't looked at the brightest ones through a scope yet

[25585]

There are F (yellow-white), G (yellow), K (orange) stars in the Pleiades. Only 41 of the 500 are B (blue, including the brightest), O (blue but less hot) & A (white). 

White Dwarves spectra have been discovered in the Pleiades (source Spectral Atlas for Amateur Astronomers). 

Interstellar matter can make stars appear redder than they actually are. So can our atmosphere if the altitude is low enough. 

[Stu]

There's a big difference between stars and nebulae in terms of the colour you see.

Stars are effectively point sources so the  colour seen from them is much more concentrated than when spread out as it is in low surface brightness objects such as nebulae.

I've not done much observing of carbon stars for instance, but recently spotted Hind's crimson star which had very clear red colour.

As for nebulae, like others I see the most noticeable colour in planetary nebulae, the Blue Snowball of course, but also green in the Blinking Planetary for instance.

When I first started observing I did not notice (or remember) any colour in m42. Now though I see it with a green tint even in a 4" refractor. I think avoiding getting fully dark adapted helps see colour in the brighter nebulae, a strange example of where a little LP might actually help by keeping your cones stimulated.

[John]

When doing outreach sessions, I've noticed that seeing colour in astro objects comes a little easier to younger eyes. Many of our younger visitors comment on star colours and the greenish tint in Messier 42 unprompted but we usually need to invite older observers to say what colours they see and the response is quite often a little hesitant ..... "well I think I can see that x is a different tint to y..."  

 

[25585]

I remember what disappointed me most was not seeing M31 with an orange core, or any globular cluster likewise, given that those are mainly orange to red Population II stars (older later Main Sequence) & red light travels further than any other.