should i see colour?

hey guys

Got my first scope celestron 114mm reflector EQ. Its great!
Ive been out 2 nights with it and have seen Saturn and the orion nebula so far.

My question is when i look at Saturn its got no color to it , nor does the orion nebula ... its almost black and white.

I live in Sydney - manly , very close to the CBD so is this because of light pollution?

Or is my scope not good enough ?

Thanks in advance, Ash

[matt]

In an nutshell? Nope...there's nothing wrong with your scope.

It's mostly to do with your eyes. They're just not sensitive enough to the very low levels of light to reveal much colour.

Even in my 9.25" scope the Orion neb is pretty much black and white.

Saturn shows a predominantly gentle yellow/gold colour with hints of a red equatorial band occasionally.

Jupiter offers a little more in the way of colour, but that's an early morning object at the moment. Wait a month or two...but even then it's quite subtle.

So don't worry. Your scope is fine. Look more for detail than colour

There are plenty of stars to view which will show you colours...end even double stars where the colours are different.

Well its good to know nothing wrong with the scope!
Thanks!

So my question would then be , all these images of planets and nebula's that are posted on this site and all over the internet , how come they are in color?

Also do filters add color?

Sorry for the noob questions, still learning alot

[matt]

Well...that's because cameras give us the opportunity to expose the chip (CCD) or film longer, and thus capture more photons

Longer exposures allow more light and colour to be captured.

This is a very simple explanation...BTW...but that's pretty much it.

Filters, when used for visual, help bring out details...while filters used photographically help produce a composite image. So, in the case of planetary imaging, we capture a red, green, and blue image and then combine it to form a single (RGB) colour image.

Ahh i see i see!
awsome thanks , i get it now

[RAJAH235]

It's just that your retina transfers the received photons instantly to your brain.
Hence no colour in low light. Not enough time.
As explained, a film, CMOS or CCD has more time to collect the photons before storing.
Think in reverse.
In daylight the exposure time is very short but at night it has to be increased.
Your eye cannot do this 'increased time' process.
Simple.

[Night Owl]

There have been many people see telescopes for sale at department stores and the like, and are lead to believe that through a cheap scope, even with "750X magnification", you will see spectacular images the likes of which appear on the box! I don't think I've ever seen a disclaimer that states you will not see those images, or the splendiferous colours, as printed on the box, due to the fact they were originally imaged by the Hubble Space Telescope!

Unfortunately its the astronomy equivilent of anti aging creams, milkshake diets, and ab-blasters...

[vindictive666 (John)]

i have seen a slight tinge of green in the Orion Nebula

[iceman (Mike)]

Saturn should definitely have some colour, but in a small scope it will be very subtle. Mostly a pale yellowish.

In very good conditions, you'll see more shading on the globe but the smallish scope will always be limited to what it can resolve.

Collimation is also very important for any newtonian, so make sure you have a read about how to do it. It's a bit scary for someone new, but if you can get along to a local meetup or astro club, they'll show you how to do it and you'll see it's not so scary after all.

[mark3d]

we usually see a tinge of green to the orion nebula after looking for a while, or after a few quick looks, but on first glance it just looks white.

i cant wait to see coloured stars! any good examples to suggest? esp. different coloured doubles!

[Screwdriverone (Chris)]

Hi Ash,

As an aside to answer your original question, the reason you cant see any or much colour through your scope is because:

1) Its night time and dark.
2) Humans have two sets of light gathering objects (photoreceptors) in their eyes, rods and cones. This is due to survival requirements and evolution.
3) There are much more rods in your eyes (about 120 million) than cones (about 7 million) but the rods are very sensitive to light in the dark, however do not have very much colour distinguishing characteristics.
4) The rods are situated around the outside of the eye, (think of a donut, mmmmmm donuts arrrrrrr) whereas the cones are very sensitive to colour and are situated more in the central part of the eye.
5) The cones are responsible for detecting the colour we see during bright light (ie daylight) as the pupil contracts centrally and focuses this bright light toward the centre of the eye and because it is rich in colour during the day, the cones are more numerous in that area.
6) At night, the eye's pupil dilates or stretches out centrally to try and gather as much light in to the eye as possible to allow us to see. As such, at night time, we need MANY more rod cells to detect the available light and make out details and ultimately detect threats such as predators using the outer part of the eyes and our peripheral vision.
7) You will have probably have noticed the cones "switching" over to the rods at night when you close your eyes and try to go to sleep. The colour waves and shapes you see behind your eyelids when you go to sleep are the cones switching off and the rods beginning to take over as your eyes become accustomed to the dark.

With these items in mind, while you are at the scope, its a very good idea to try and keep your eyes dark adapted by not looking at any bright "white" lights such as street lights and such as this will impair your night vision and cause your rods and cones to try and switch over. This is why it is recommended to use a red light to see at night as this is less disturbing to your night vision.

Also, when trying to make out some details at your scope, you will often be recommended to use "averted vision" which is when you do not look directly at a faint object but just off to the side of it. This will expose the light coming in your scope and through your eyepiece to the much more sensitive rod areas of your eyes and show you more details. It takes a bit of getting used to, but soon you will easily get the hang of it.

A bit of an essay to read but I hope it answers some of your questions in a bit more detail.

Here endeth the lesson....

Chris

[erick (Eric)]

There are some interesting comments on seeing colours in this thread:-

http://www.iceinspace.com.au/forum/s...ad.php?t=26916

It's worth noting from the Chris' excellent rods/cones discussion that using averted vision is not the way to see colour.

A good practice for training your brain to see colour is DY Crucis near Mimosa in the Southern Cross. Look for threads on it - and a recent photo on this forum from Peter Ward. After a while, it gets easier to pick out the red star in the presence of a bright star. You wonder why you never saw it before it becomes so distinctive.

Q. Given Saturn is clearly cream coloured to the naked eye (well it is to mine), surely it should clearly show colour with magnification? Edit: I guess I'm asking - does magnification increase or decrease colour perception? Not quite the same issue, but I know of the trick to defocus stars to more clearly see what colour they are.

[Kal (Andrew)]

Mars will be red, Uranus blue, and Neptune greenish even with small aperture. For deep sky objects, as already stated, colour is very hard to see, even with large aperture.

[ving (David)]

Originally Posted by mark3d

i cant wait to see coloured stars! any good examples to suggest? esp. different coloured doubles!

i have a double star blog linked in my signature with lists of double in them, feel free!


in my 8" orion neb is a definite green colour, bright green even...
sature has subtle colour bands to it much like the pictures but more subtle... alot more.

[erick (Eric)]

Originally Posted by ving

i have a double star blog linked in my signature with lists of double in them, feel free!

Yep, Ving is the source of all that's double!

A couple of easy and nice colourful pairs for beginners like me:-

1) x Velorum - easy to find at the moment - see in this article here:-

http://www.iceinspace.com.au/index.p...69,198,0,0,1,0

2) Albireo in Cygnus - but you need to wait until the depths of winter for an evening view.

[Paddy (Patrick)]

Just a tad to add to Chris' excellent post on night vision, from a reformed physiologist. The reason that cone photoreceptors give rise to colour vision is that there are three populations of them, each maximally sensitive to a different wavelength of light. The brain sorts out colour by comparing the relative activity of each population for each part of the visual field. The rod cells are much more sensitive, but there is only one population of them, so the brain cannot work out colour from their signal - so night vision is monochrome.Only when there is enough light to stimulate the less sensitive cones (eg when viewing planets) will you see colour.

[Craig.a.c (Craig)]

I was often puzzled as to why I never saw any colour when looking at few of the planets and the orion nebula. I asked a few people and was told that with larger telescopes, 12" and greater, some colour would be a little visable.

[Kokatha man]

Mars is red
and Venus is white
but if Uranus is green
somethings not right...

...sorry

[OneOfOne (Trevor)]

Can't quite remember at the moment, but of Uranus and Neptune....one is greenish blue and the other is bluish green...or was that vice versa. Even when I had my 8" Newt, I could make out very feint colours in both planets from my suburban backyard....but if someone just casually looked they may not have noticed the colour. Mercury should also have a very slight reddish tone...

Usually a lack of colour is one of the things that beginners are disapointed about...so was I.

[Screwdriverone (Chris)]

Hey Kokatha Man,

Just thought I would comment on the joke, it made me laugh, placement was everything....

Just a little disappointed that apparently no-one has seen my excellent spider joke...sniff.

Thanks Paddy, the three types of cones brought the rest of the science lesson back to me from High School. I must be getting old, my long term memory is now starting to scare me.

Chris