How hard is it to see Orion Nebula?

[Slimstar]

Hi, 

Just need to check what I am missing to see Orion Nebula. I was able to see Jupiter and its 4 moons quite clearly at 72x magnification but when I look at Orion Nebula, all I see are a few stars with a faint lighter shade in the background, is that the Nebula? Is it normal to not be able to see the colours of it? Is the magnification enough?

[John]

The nebula is normally in grey scale even through quite large scopes. There is quite a bit of it under a dark sky even with a 4" scope. It can be seen with 8x30 binoculars and even the naked eye. The colours you see in images are not available visually I'm afraid. Use as low a magnfication as possible to view the nebula - too much magnification and you only see part of it and it will seem much less impressive. Something like 25x - 40x is good.

[Qualia]

Just to give some idea to John's sound insight, this is a sketch I made with a 4" frac at a reasonably dark site. Of course, this kind of thing isn't seen immediately, one has to spend time at the eyepiece tweaking detail from the object and building it up over a given amount of time. I cannot remember exactly, but a sketch like this will take me about 45 to 60 minutes of quite intense work.

[ronin]

Not difficult to see, it is about a degree across (outer edges are dim as they are not illuminated byt the central stars). So 50x should squeeze in all of it. If you go higher as in 100x then you see the central portion and the central trapesium stars become apparent.

If I recall for "colour" you need a scope of about 14" to 16", and if you get any clour coming through it tends to be a faint hint of green.

In the absence of any planets people will be observing the Orion nebula to death.

From your description it sounds a little underwhelming, so I would check that what you are actually observing is M42 as even in 8x binoculars it shows up as a small patch of nebulosity so in a scope at 72x I would have expected more then what you describe. Drop the magnification a bit. M42 is the main bit, above that is M43, then above both of these are NGC 1977 and NGC 1981 and above these come the belt stars.

I doubt you have the Horsehead Nebula as it is much dimmer.

Sort of above the belt and a bit outside of it is M78, another nebula, dimmer then M42 but not a greatlly different shape.

Only mention these as if the scope ends up with one in view it can be easy to presume you have M42 - there is aftrall a nebula in sight. Drop the magnification and make sure that you are aiming at M42 first.

[Ruud]

You'll see it better if you use averted vision. That means that you look away a little from the object, while you keep your interest focussed on it.

It has to do with the distribution of cones and rods accross the retina. Outside the central portion, the retina is more sensitive to brightness differences.

Averted vision makes a big difference for the Orion Nebula at low magnifications. At 15x you can make it seem much bigger when looking slightly away. When you look back at the trapezium, the nebula immediately shrinks back.

[Dave In Vermont]

I can discern colour in M42. Always could. It's one of the very rare DSO's that some folks can detect a reddish and bluish shade to. But I also have different eyesight from most people. I have monocular-vision - inherited - which means I use, alternating, one eye as focus and the other as range-finder. So I normally block all vision from one side and place full attention to the other. No eye-patch required.

This may explain my ability to perceive colours where others do not. Or, perhaps, I took too much acid in the 1960's...

Clear & Dark Skies,

Dave

[ghostdance]

Never heard of monocular vision....sounds fascinating, Dave! Must be something to perceive colours that others can't.

Tho personally, I'd favour the second reason if it was me :D

[jetstream]

Qualia's sketch is great, and my 90mm shows it like this from dark skies and with a hint of green. From lighter skies with a UHC/OIII the wings are seen with a bit less nebulosity and none in the surrounding area. In the 10" from very dark skies the nebula is huge with the core a bright marbled turquoise and hooks and curves showing in the wings. I find no filter is best under these circumstances. I've never seen red or any other color in it though.This sketch is similar

This is a stunning object, one of my favorites.

[Slimstar]

Thanks for the explanation. Really helpful, the sketch really explains it. 

Just some basic follow up questions. So I should not expect any colour from all the nebula as the colours are only possible with very high powered telescope right? Is it the same with galaxies?

[jetstream]

Color is mostly impossible, only a few objects may show it to a few people, regardless of aperture. Most nebs are a faint ghostly grey and are best viewed with wide field EP's and lower powers, my best view of M42 is with a  17mm EP @ 70x in the 10". Planetary neb will take much higher mag.

For most galaxies an exit pupil of 2mm-2.5mm is very good, M31 an exception as its so big in the EP already. What scope do you have?

[Dave In Vermont]

Thanks for the explanation. Really helpful, the sketch really explains it. 

Just some basic follow up questions. So I should not expect any colour from all the nebula as the colours are only possible with very high powered telescope right? Is it the same with galaxies?

"high powered" infers magnification is necessary to view DSO's (deep sky objects) and other dim things. It is NOT how much magnification you use, it is the aperture of the telescope. The bigger the lens/ or mirror, or both, the more you will see. For DSO's, often a lower power is needed to see them at all.

The challenge is finding them at all and using things like 'averted-vision' to glean finer detail from them. But the higher the power you use while hunting these, the narrower your Field-of-View (FOV) will be - usually. So find it first - and then tinker with what will benefit your view.

Clear Skies,

Dave

[Slimstar]

Color is mostly impossible, only a few objects may show it to a few people, regardless of aperture. Most nebs are a faint ghostly grey and are best viewed with wide field EP's and lower powers, my best view of M42 is with a  17mm EP @ 70x in the 10". Planetary neb will take much higher mag.

For most galaxies an exit pupil of 2mm-2.5mm is very good, M31 an exception as its so big in the EP already. What scope do you have?

Thanks Gerry, will try again tonight.

I am using Celestron 130slt, at 9mm EP, i am getting about 72x magnification

[Slimstar]

"high powered" infers magnification is necessary to view DSO's (deep sky objects) and other dim things. It is NOT how much magnification you use, it is the aperture of the telescope. The bigger the lens/ or mirror, or both, the more you will see. For DSO's, often a lower power is needed to see them at all.

The challenge is finding them at all and using things like 'averted-vision' to glean finer detail from them. But the higher the power you use while hunting these, the narrower your Field-of-View (FOV) will be - usually. So find it first - and then tinker with what will benefit your view.

Clear Skies,

Dave

Got it, thanks Dave

[philhas]

If you want to see it in colour take a look at the Video Astronomy pages, some good and cheap ways of live viewing objects in colour although you will need a motorised mount.

[nicoscy]

Thanks Gerry, will try again tonight.

I am using Celestron 130slt, at 9mm EP, i am getting about 72x magnification

Use less magnification as nebulosity is better seen with larger exit pupils. The 25mm that comes with your scope should be better suited to the task.

[Moonshane]

most of the comments about using low power (magnification) are quite correct for larger objects but I regularly use higher powers for things like planetary nebulae and small galaxies otherwise they are almost impossible to split from stars. PN's sometimes show colour, usually greenish or bluish tones (e.g. the blue snowball NGC 7662).

[nicoscy]

Yes, but for extended objects with low surface brightness, a large exit pupil is a requirement, therefore lower magnification is required.

[Slimstar]

If you want to see it in colour take a look at the Video Astronomy pages, some good and cheap ways of live viewing objects in colour although you will need a motorised mount.

I am quite lost on this

[swamp thing]

Use less magnification as nebulosity is better seen with larger exit pupils. The 25mm that comes with your scope should be better suited to the task.

^^^ This is exactly what I would advise when observing large diffuse nebulae.