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musrol

How to see nebulae in colour?

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I was looking at the Orion nebula through my new SkyWatcher 150PL and it looked fantastic. However I was wondering how you can see it in colour instead of black and white? Do some filters allow you to see more colour?

Being new to astronomy I also don't really understand why people reccomend looking at nebula through a relatively wide angle EP, why not an EP with the highest magnification so you can see it closer? I was looking at it with the supplied 10mm and X2 Barlow.

Sorry if these questions seem silly and thanks in advance

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The best way to see nebulars in colour is to buy an astronomy book full of glossy and grossly misleading Hubble type images...........

Or get your self to the hugest big scope possible perhaps...........

Magnification will reduce the contrast, making the nebulae even fainter. A wide, long focus EP will retain the contrast. Large aperture scopes gather more light, which in turn increases the contrast until eventually, so I believe, you start to see colours. I've heard 20" mentioned somewhere, I'm sure, to be able to see any descernable colour. But I'm still a novice, so don't just take my word for it.

Edited by yeti monster

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The eye isn't sensitive to colour at low light levels...next time you go outside when it's getting dark, watch and see how quickly everything becomes greyscale.

There are very few deep space objects (DSO's) that it is possible to see in colour, even in the largest scopes...M42 is one, and M57 is reortedly another.

I've heard that you really need a 36 inch scope and above.

The colour you see in photographs is the result of very sensitive detectors being pointed at the same area of sky for many hours.

Re. magnification. The higher the magnification, the smaller the area of sky that you're looking at. Something like M42 is actually quite large, so at high power you will only see a little of it.

Also, the more you increase magnification, the dimmer the view becomes, meaning that for higher powers, certainly with DSO's, you need a bigger scope to gather more light in the first place.

Actually...higher magnification increases contrast, not the other way round.

The reason is that, especially in areas of light pollution, the background sky glow becomes less of a problem at higher power, as you are seeing less of it. The reason it can seem to decrease is the loss of light I described.

The other thing about high power is that it depends very miuch on the atmospheric conditions (seeing). If the seeing is bad, high powers will just show you a wobbly mess, where a lower power will give a better view.

The general rule of thumb is that, with a good scope and the best seeing, 50x per inch of aperture is the most you will get out of it, 30x being generally more realistic.

Hope that helps :)

Cheers

Rob

Edited by RobH
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I've only ever seen greys and a faint hint of green in nebulae. The Blue Snowball planetary in Andromeda does show a hint of blue, but I found it very subtle.

For colours look at the stars.

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Some nebulae are small and tight (eg: M57 - the Ring Nebula) and benefit from higher magnification. Some though are huge and sprawling and will hardly fit in the field of view at very low power with wide angle eyepieces. The Veil Nebula (which has a number of parts) needs a 4 degree true field of view to fit it all in - that's 8x the diameter of the moon. So the answer is to use a magnfication that suits the angular size of the object you are looking at. The apparent size of DSO's is something that the photos don't really help you grasp as there is nothing for scale - some are a lot smaller or larger than you think and for that reason it's easy to miss them altogether sometimes.

Edited by John
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some are a lot smaller or larger than you think and for that reason it's easy to miss them altogether sometimes.

Yes i've made that mistake a few times when hunting for tiny planetary nebula. M76 springs to mind. Tried finding it with a 32mm eyepiece and a large field. It must have gone through the field a dozen times before i realised a medium power eyepiece (16mm) was actually the order of the day. And even then it was small. Really required a higher power still.

Can't say i've ever seen colour, not even a hint, in any nebula. Double stars are the best bet for amazing colour in the eyepiece. Start with Albireo, the colour contrast is truly stunning.

Russ

Edited by russ
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On very good seeing nights, without moonlight and in a very dark observing spot I get to see a green tint to the orion nebula. As on power I use 4 magnifications mainly: 37x (for widfield), 80x for smaller DSOs or scanning the inside of big ones, 120x and 240x (planets, moon, double stars and some tiny DSOs (clown nebula for example)). Other magnifications to fill the gaps are nice to have but I rarely use them.

Specifically on the Orion nebula, I like to observe it with any mag. The wide field allows me to see the full size of it under dark skies, while the high mags allow me to scan the area near the trapezium and the added contrast+mag allows to see structure in that area, almost like cotton threads folded and twisted together (this requires excellent seeing conditions, good collimation and it stands out with my orthoscopic EPs, other EPs fail to show as much contrast thus making the structure less noticeable).

Another great one is the veil nebula with an amazing structure, though it's so faint I need an OIII filter to bring it out and the widest field I have to see it. Any mag on the veil makes it too faint for detail. I find the max mag I can use on the veil is around 80x and it requires some averted vision with the filter. Without the filter I can barely detect it with only the wide field EP, others make it "disappear".

I would advise you to get at least those 4 mags (or similar) available to you and experiment. If you want to add a nebula filter to your stuff then the UHC is less aggressive and probably more suited for a 6" scope, when compared to the OIII. I must warn that the nebula filters don't get much use, unless of course that's your main interest, and they are a bit expensive.

Edited by pvaz

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I think for Orion the smallest scope I have read reference to that made out colour was a 16 inch.

Orion is, by comparison, very bright. The orion nebula is easily seen by eye, however try the same with Andromeda. After that they get worse.

As to filters, they are called filters because they filter out light:eek::) they do not add. Look at it this way sunglasses are neutral density filters.:D:D

As said magnification makes what you are looking at dimmer. Scope collects the same amount of light and magnification makes the final image bigger. So it is dimmer.

So for the possibility of colour then magnification is the last thing you want, low magnification will collect the gathered light into a smaller final image and so a smaller but brighter image.

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I can see a green tint to M42 at x100 with my 10 inch, but I can see no colour in any other nebulas. Adding a UHC filter for example will give everything a greeny blue colour including star light.

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Thanks for all your replies...really useful to know all that. Just praying for clear skys so I can experiment with different EPs a bit more now.

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i can see greenish colour in the orion neb on a good night with the 10" dob but only since i got a half decent eyepeice, using a bog standard shywatcher or (to my eyes) the better celestron 25 mm that came with the c80 ed just showed a grey image

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On 21/01/2010 at 13:52, musrol said:

I was looking at the Orion nebula through my new SkyWatcher 150PL and it looked fantastic. However I was wondering how you can see it in colour instead of black and white? Do some filters allow you to see more colour?

Being new to astronomy I also don't really understand why people reccomend looking at nebula through a relatively wide angle EP, why not an EP with the highest magnification so you can see it closer? I was looking at it with the supplied 10mm and X2 Barlow.

Sorry if these questions seem silly and thanks in advance

4.5'': m57_5_600.jpg

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This is a 9 year old thread.

 

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By chance I came across a review of the Vaonis "Stellina" smart scope in Nov. 2018 edition of Astronomy Now. The scope focuses its light directly onto a 6.4 megapixel CMOS sensor and the image is relaid to a smart phone/tablet app which makes use of 'image live stacking' using 'target-adapted processing to obtain the best clarity'. From the looks of things, this is capable of displaying nebula colour, though personally I wouldn't want one, even if I could afford it:- https://youtu.be/4du2xxYXfhM

 

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20 hours ago, Aramcheck said:

By chance I came across a review of the Vaonis "Stellina" smart scope in Nov. 2018 edition of Astronomy Now. The scope focuses its light directly onto a 6.4 megapixel CMOS sensor and the image is relaid to a smart phone/tablet app which makes use of 'image live stacking' using 'target-adapted processing to obtain the best clarity'. From the looks of things, this is capable of displaying nebula colour, though personally I wouldn't want one, even if I could afford it:- https://youtu.be/4du2xxYXfhM

 

Many of us have been replicating this for some years. You don't need an all in one device. I use a Celestron Evolution telescope; Hyperstar (hence at f/1.9); Atik Horizon OSC camera (16 megapixel) and similarly use short stacked exposures to create near live viewing. I then wirelessly transmit the images to a computer indoors and view on a 4K UHD monitor.

It's generally referred to as Electronically Assisted Astronomy (EAA) but here in SGL they now call it EEVA (Electronically Enhanced Visual Astronomy).  I guess the latter is aimed at emphasising its about viewing and not about imaging, albeit the use of a camera seems to enrage some visual astronomers. But it's the only easy way to witness colour in nebula, but still not cheap.

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As I'm sure others have posted (haven't read the whole thread yet), most nebulae will not show much if any colour with direct eye viewing. 

Luckily for us all, there are some exceptions. I can't list them off the top of my head other than the Blue Snowball nebula does show its colour clearly through my XT8. It's quite lovely to see after the usual grey smudges and shapes most display. 

Personally, I have never seen any hint of colour with M57, although it's still currently my favourite DSO target. 

 

Cheers

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On 04/11/2019 at 19:24, Aramcheck said:

By chance I came across a review of the Vaonis "Stellina" smart scope in Nov. 2018 edition of Astronomy Now. The scope focuses its light directly onto a 6.4 megapixel CMOS sensor and the image is relaid to a smart phone/tablet app which makes use of 'image live stacking' using 'target-adapted processing to obtain the best clarity'. From the looks of things, this is capable of displaying nebula colour, though personally I wouldn't want one, even if I could afford it:- https://youtu.be/4du2xxYXfhM

 

Holy crapola! $3999!!!

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If you want colour some of the stars give nice visible colour that you can see.  Albireo in Cygnus is possibly the most well known.  It is a double star and each of them is a different colour.

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On 09/11/2019 at 03:36, MKHACHFE said:

Personally, I have never seen any hint of colour with M57, although it's still currently my favourite DSO target. 

I have - in 5" scope! Well - it was not color as we normally see it - it was more "impression" of the color, or rather feeling that leaves you wondering if you saw color at all or your mind is playing tricks on you by relating what you see to the images of object you saw before and knowing in principle what color it should be (mind you - it did not happen to me on other objects regardless of the fact that I also saw and remembered their color images).

Part of the trick when trying to see color is not to get dark adapted. Once you get dark adapted - even light levels that should produce color response get contrast loss and you start not to see color at the level you should. This is also important when observing planets - you will loose both color fidelity and perception of detail if you fully dark adapt.

In fact, I think it is related to this:

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

 

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The blue snowball looks pale blue in a 4". In a 6" it has an obvious cyan hue. For me it is the only nebula that shows any colour.

It's a very compact nebula. That must help.

Here is a finder chart for it from https://freestarcharts.com/ngc-7662

 

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