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gorann

Traveling close to M42

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Grey skies, so I have been playing around with processing, learning star removal, so I came up with this version of M42. I first thought it looked rather odd, but then realized that this is what it may look like if you travel there and end up close by, with most of the stars we see from Earth behind you........

(ES 127ED apo withh 0.79x TS reducer, NEQ6, Canon 60Da, ISO 1600, 46 x 3 min)

IMG_806-850+41%885-905final fixNoStars.jpg

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Actually, I get more of a feeling of being there when I turn it this way........

IMG_806-850+41%885-905final fixNoStars.jpg

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Outstanding picture, how long does it take from starting with astrophotography to producing images like this.

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Thanks Deano666

it does not have to take that long. I took my first AP in March 2015, and I have had less that 20 nights doing AP under a clear sky since then. That also means that I have spent more time in learning processing than in catching photons. I need to reverse that. Also, M42 is one of the brightest objects around so it is a good one to start on.

On 2016-01-29 at 15:30, Deano666 said:

Outstanding picture, how long does it take from starting with astrophotography to producing images like this.

 

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Really nice image. Very clear and full of detail. Colour and the processing are, I think, a matter of personal taste. A while ago I was on an Americans web site. He stated categorically that he liked to produce nice images, pretty images that he was happy with. They were not supposed to be absolute accurate images, just what he preferred!

I like that sentiment. I like nice images and the colour is just that,  a colour. There are several different colour pallets to choose from. Each to his/her own. 

 

Derek

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Thanks Derek!

I expect that virtually everyone doing AP for fun alter the images to be pleasing to the eye. After the first stretch, the image is no longer an accurate recording of light intensity. Taking away stars, like I did in this one, may be a bit too far for some, maybe also me, but as long as we are honest about what we have done I think everything is OK.

 

By the way, this is what it looks like with all the stars...........

IMG_806-850+41%885-905final fix90degrees.jpg

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Please dont take my comment on the magenta as criticism it was merely a reflection of my preference hence i said "maybe" and not "definitely". And by the way my preference is with the extra stars rather than without.

Edited by symesie04

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13 hours ago, symesie04 said:

Please dont take my comment on the magenta as criticism it was merely a reflection of my preference hence i said "maybe" and not "definitely". And by the way my preference is with the extra stars rather than without.

I like the idea of removing the stars to give a sense of being closer to the nebula and comparing the two, I think it has been achieved to some degree. The image with all the stars looks flatter with no feeling of perspective - or is it just me???

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On 27/01/2016 at 22:54, gorann said:

this is what it may look like if you travel there and end up close by, with most of the stars we see from Earth behind you........

 

I like the image but I'm not sure it would look anything like this in reality. I read somewhere recently that none of he DSO's we photograph from Earth would actually look like they do in pictures as what you are actually looking at is enormous and very thin clouds of gas which would be invisible to our eyes. If we could see this stuff the guys on the ISS wouldn't see any black sky :wink:

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Thanks for all the comments, I like them all!

I agree that the version with all the stars has less perspective somehow. I also think that there is a striking loss of perspective when the image is at a 90° angle (i.e. with M42 to the right rather than on the bottom), as in the first post in this thread. That is easily explained by the way we normally see things, with the sky on top, and in this image it looks like we are standing close to M42 and there is a dark sky on top. It may be a pity that most images of M42 and the Running Man are shown in "landscape" orientation, side by side. I assume this is just because it fits better on our computer screens.

What it would look like if we got closer depends on how close we get. If we were 130 light years away, rather than 1300 as we are now, it may look a bit like in the pictures we take. At that distance it would be 100 times brighter and 10 timer larger. At 13 light years, the trapezium would be 10 000 times brighter and may be so dominating that all faint stuff would be invisible (and also spread out over a 100 times larger area, filling our whole field of view). All according to the Inverse Square Lav (https://en.wikipedia.org/wiki/Inverse-square_law)

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46 minutes ago, gorann said:

What it would look like if we got closer depends on how close we get. If we were 130 light years away, rather than 1300 as we are now, it may look a bit like in the pictures we take. At that distance it would be 100 times brighter and 10 timer larger. At 13 light years, the trapezium would be 10 000 times brighter and may be so dominating that all faint stuff would be invisible (and also spread out over a 100 times larger area, filling our whole field of view). All according to the Inverse Square Lav (https://en.wikipedia.org/wiki/Inverse-square_law)

I agree with all of that, Göran, it is the coloured gaseous regions that I am talking about. Our eyes simply do not see the same wavelengths of light that you can detect and then process through a camera lens and software. Much of what is seen as coloured gas clouds in pictures would be either invisible or at most a dull haze to our eyes regardless of how close we were. If we were in the middle of M42 we wouldn't even know it was there with our eyes alone.

Edited by DRT

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2 hours ago, DRT said:

I like the image but I'm not sure it would look anything like this in reality. I read somewhere recently that none of he DSO's we photograph from Earth would actually look like they do in pictures as what you are actually looking at is enormous and very thin clouds of gas which would be invisible to our eyes. If we could see this stuff the guys on the ISS wouldn't see any black sky :wink:

It would apart from some of the colours are not quite right.

Unmodded DSLRs offer natural colour, almost exactly what our eyes see.
Where as modded DSLRs shift everything to more red dominating other colours.

If we take M42 in natural colour, it should be mostly blue, Rayleigh scattering, pink/magenta which is Ha emission, in the centre.
Around the Trapezium should be teal, a greenish blue, from doublely ionized oxygen.
All around the nebula should be orange to brown dust.

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31 minutes ago, DRT said:

I agree with all of that, Göran, it is the coloured gaseous regions that I am talking about. Our eyes simply do not see the same wavelengths of light that you can detect and then process through a camera lens and software. Much of what is seen as coloured gas clouds in pictures would be either invisible or at most a dull haze to our eyes regardless of how close we were. If we were in the middle of M42 we wouldn't even know it was there with our eyes alone.

But we do see these wavelengths of light.

We see about 20% of Ha, 40 and 20% of Oxygen, nearly 30% of Hydrogen Beta and 10% Hydrogen Gamma.

These emission lines are very narrow and the colours should shine like neon, so if your close to it you will see it.

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Gorgeous images Göran. I can't make up my mind whether having stars or not is preferable, but I'd be happy to produce either!

Ian

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I'd suggest you google this topic and try to find anyone who agrees with you :wink:

The bottom line is our eyes cannot detect these colours from these objects regardless of distance. The surface brightness does not change regardless of how close or far away you are and our eyes see almost no colour in darkness. Regardless of what Gene Roddenberry made us believe, our Starships could not hide in a Nebula because when you get there it can't be seen :smile:

Edited by DRT
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2 hours ago, DRT said:

I'd suggest you google this topic and try to find anyone who agrees with you :wink:

The bottom line is our eyes cannot detect these colours from these objects regardless of distance. The surface brightness does not change regardless of how close or far away you are and our eyes see almost no colour in darkness. Regardless of what Gene Roddenberry made us believe, our Starships could not hide in a Nebula because when you get there it can't be seen :smile:

I tend too agree with Gorann's logic. DRT - I am not sure why you say we can't see these narrow band wavelengths. They are all in the visible light range. The reason we can't sense the colors is that our eyes are less sensitive to color when the intensity is low, our rods being more sensitive than our cones. In fact with large telescopes - 18" or 20" people have reported seeing color in the Orion Nebula. I imagine if we were a lot closer then the nebula will be brighter (inverse square law) and we will see  the color. According to Wikipedia the nebula is about 24 light years across - a larger distance than that to some of the brighter stars we see. If we were inside it I believe there is the chance of seeing the nebulosity of more distant regions to where we were. In 1910 the earth passed through the tail of Haley's Comet which could be seen almost all the way across the sky. It might be similar for some filaments of ionized gas in the Orion Nebula (I couldn't decide on which emoticon to put here !!!!??? ). 

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I can only go on what I have read, and I have yet to find any source that claims we would see a Nebula in any way close to what we see in astro photography. They simply do not look like this to our eyes or brains.

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3 hours ago, beka said:

I tend too agree with Gorann's logic. DRT - I am not sure why you say we can't see these narrow band wavelengths. They are all in the visible light range. The reason we can't sense the colors is that our eyes are less sensitive to color when the intensity is low, our rods being more sensitive than our cones. In fact with large telescopes - 18" or 20" people have reported seeing color in the Orion Nebula. I imagine if we were a lot closer then the nebula will be brighter (inverse square law) and we will see  the color. According to Wikipedia the nebula is about 24 light years across - a larger distance than that to some of the brighter stars we see. If we were inside it I believe there is the chance of seeing the nebulosity of more distant regions to where we were. In 1910 the earth passed through the tail of Haley's Comet which could be seen almost all the way across the sky. It might be similar for some filaments of ionized gas in the Orion Nebula (I couldn't decide on which emoticon to put here !!!!??? ). 

I have to agree with Beka. All the "narrowband" wavelengths (Ha, OIII and SII) are well within the range of what the cones in the human retina will detect (390 - 700 nm) (trust me, I am a professor of physiology). In any case, my image was taken with a DSLR with the normal IR and UV filters, cutting off the wavelengths that are invisible to us, below 390 nm and above 700nm, so what the camera sees we can also see. The only difference is that the Canon 60Da has a 3-fold increase in Ha sensitivity, so the image will look a bit more red than what we would perceive, but even with an unmodded-DSLR (made to be very similar to the sensitivity of the human eye), I believe this nebula is reddish, but not quite as red as here.

By the way, thanks for all the compliments!

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Very nice, nothing wrong with colourful images as far as I'm concerned, on the stretching subject, I don't think linear stretching as in P'Shop levels alters the data, curves is another matter.

Dave

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1 hour ago, gorann said:

so what the camera sees we can also see. The only difference is that the Canon 60Da has a 3-fold increase in Ha sensitivity, so the image will look a bit more red than what we would perceive, but even with an unmodded-DSLR (made to be very similar to the sensitivity of the human eye), I believe this nebula is reddish, but not quite as red as here.

So your eyes are capable of taking 46 x 3 minute exposures (equivalent to a 2hr 18min unblinking stare), stacking them one on top of the other and then allowing your brain to process them for hours before deciding what you just seen?

That's impressive :wink:

I think I will just retire back to the observation section and look at grey fuzzy things with my inferior eyes :lol:

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5 hours ago, beka said:

I tend too agree with Gorann's logic. DRT - I am not sure why you say we can't see these narrow band wavelengths. They are all in the visible light range. The reason we can't sense the colors is that our eyes are less sensitive to color when the intensity is low, our rods being more sensitive than our cones. In fact with large telescopes - 18" or 20" people have reported seeing color in the Orion Nebula. I imagine if we were a lot closer then the nebula will be brighter (inverse square law) and we will see  the color. According to Wikipedia the nebula is about 24 light years across - a larger distance than that to some of the brighter stars we see. If we were inside it I believe there is the chance of seeing the nebulosity of more distant regions to where we were. In 1910 the earth passed through the tail of Haley's Comet which could be seen almost all the way across the sky. It might be similar for some filaments of ionized gas in the Orion Nebula (I couldn't decide on which emoticon to put here !!!!?

I would disagree with the point about the nebula appearing brighter when you get closer. I believe that as the nebula gets closer, it's absolute brightness remains the same but the surface area increases so the surface brightness remains constant too. It will appear larger in the sky but on a per unit area basis, it will be the same as it was at a distance. It is not like a point source star which does get brighter the closer you get....

I also understand that the density of these nebulae is extremely low, so you may well not be aware of them if you were very close or buried inside.

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This is getting interesting,

Stu, I think you nailed it. If you get 100 times closer, i.e. if you get to 13 light years from M42 (which is now at 1300 light years), the nebula would be 100 times wider, and the nebula area would be 100 x 100 = 10000 times larger, which is the same as the increase in light intensity, so the surface would be as bright as seen from here, which is very faint with the naked eye (=we cannot see it). On the other hand, the trapezium stars would also be 10000 times brighter, and since we can see them well from here, they would be extremely bright (better bring your sunnies on this trip!). So, I think I was right when I suggested that the trapezium would be so dominating that all faint stuff would be invisible. Conclusion: we can see all the wavelengths of light in the image I posted, but we would be blinded by the stars and not see any nebulosity. This suggest that we are better off at a distance. So sadly, all the pretty nebula that we image from here would slowly fade away and we would just see stars when we get there....

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