The Cocoon Nebula

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Graeme
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The Cocoon Nebula

Post by Graeme »

My telescope mount is back up and running and I was fortunate to get a new astrophotography camera for my birthday!

So here's an image of the Cocoon Nebula in the constellation Cygnus. It fits nicely in the field of view of the camera telescope combination.

32 x 240 second exposures captured last Friday night. The processing could be improved, I reduced the blue a little too much and lost the reflection nebula and gave the whole thing a red cast. But I was quite happy with it overall for a first go!

Capture EL.png

Regards

Graeme
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HansV
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Re: The Cocoon Nebula

Post by HansV »

A lovely picture, well done!
Best wishes,
Hans

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stuck
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Re: The Cocoon Nebula

Post by stuck »

Your mistake was to list the faults. Now we're all wondering what it should look like :smile: Had you simply posted the picture we'd all be none the wiser.

So I'll pretend you'd done just that and say :hailpraise: and give you a :thumbup:

Ken

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Graeme
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Re: The Cocoon Nebula

Post by Graeme »

Thanks.

The red emission nebulosity is about right and the dark nebulosity is ok but there should also be some blue reflection nebulosity as well which is quite intricate if you catch it right. And the surrounding sky probably ought to be a bit darker. I need to learn how to use layer masks!

I'm well happy with it though!

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Graeme
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BobH
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Re: The Cocoon Nebula

Post by BobH »

Brilliant, Graeme! Simply brilliant!

Thank you for sharing with us!!!!
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Graeme
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Re: The Cocoon Nebula

Post by Graeme »

Cheers Bob.

I'm hoping it's the first of many. And I hope the Lounge doesn't mind me spamming. :)

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Graeme
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HansV
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Re: The Cocoon Nebula

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You're very welcome to post your photos!
Best wishes,
Hans

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ChrisGreaves
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Re: The Cocoon Nebula

Post by ChrisGreaves »

Graeme wrote:
20 Sep 2020, 17:00
So here's an image of the Cocoon Nebula in the constellation Cygnus. It fits nicely in the field of view of the camera telescope combination.
Graeme, thanks for this great photo.
I am sure that this is something I would not have seen with my youthful naked eyes, or even with a pair of binoculars, in the nighttime desert skies in W.A.
That said, and please don't get too technical on me, the nebula as it appears in your image, which I have outlined in yellow, what arc - in degrees - would that be?
Capture EL.png
That is, if I made a cone whose apex was at my eye, a line drawn from my eye to the centre of the nebula, and a second line tracing out the surface of the cone, what angle would that second line be with respect to the centre line?
Thanks
Chris
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Argus
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Re: The Cocoon Nebula

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When Scuttle has turned into an astrophoto forum, or something else, we can talk about spamming; :grin: no one is even close to repeating themselves here, if you ask me.

Beautiful.
Some weeks ago, and still, during clear skies, I've been reminded that it's August/September; even if not living in the countryside, well some would consider it being that, and almost in the middle of the country, it was quite easy to detect several stars and "things" such as Venus and Mars, but no nebulae ... with the naked eye.
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Re: The Cocoon Nebula

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Please spam us all you want with such images, Graeme!
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Graeme
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Re: The Cocoon Nebula

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ChrisGreaves wrote:
20 Sep 2020, 20:03
I am sure that this is something I would not have seen with my youthful naked eyes, or even with a pair of binoculars, in the nighttime desert skies in W.A.
That said, and please don't get too technical on me, the nebula as it appears in your image, which I have outlined in yellow, what arc - in degrees - would that be?
That is, if I made a cone whose apex was at my eye, a line drawn from my eye to the centre of the nebula, and a second line tracing out the surface of the cone, what angle would that second line be with respect to the centre line?
Thanks
Chris

Hello Chris

The nebula is is about 4,000 light years away and 15 light years across so is about 6 arcsec across, about 3 arcsec radius.

It has a magnitude of 9 or 10 and you can't see naked eye above 5 or 6 in ideal conditions. (log backwards scale!) So no, you can't see it. The 4 stars of the bowl of Ursa Minor are a good indication of how well you can see, they are magnitude 2, 3, 4 and 5. Vega is zero. Mars is expected to rise to -2.6 in October this year.

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Gaeme
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Graeme
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Re: The Cocoon Nebula

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Argus wrote:
20 Sep 2020, 20:47
When Scuttle has turned into an astrophoto forum, or something else, we can talk about spamming; :grin: no one is even close to repeating themselves here, if you ask me.

Beautiful.
Some weeks ago, and still, during clear skies, I've been reminded that it's August/September; even if not living in the countryside, well some would consider it being that, and almost in the middle of the country, it was quite easy to detect several stars and "things" such as Venus and Mars, but no nebulae ... with the naked eye.

Jupiter and Saturn are visible at the moment to the South early evening and Mars late evening. The only naked eye nebula (Northern hemisphere) is probably M42 in Orion, but it looks like a star. Maybe the Andromeda galaxy on a good day if you have Chris' youthful eyes!

Regards

Graeme
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HansV
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Re: The Cocoon Nebula

Post by HansV »

The Andromeda galaxy is visible to the naked eye - its apparent magnitude is 3.44. It looks fuzzy without binoculars or a telescope.
Best wishes,
Hans

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Graeme
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Re: The Cocoon Nebula

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Graeme wrote:
21 Sep 2020, 06:10
The nebula is is about 4,000 light years away and 15 light years across so is about 6 arcsec across, about 3 arcsec radius.
Correction:

The nebula is about 4,000 light years away and 15 light years across so is about 12 arcmin across, about 6 arcmin radius.

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Graeme
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ChrisGreaves
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Re: The Cocoon Nebula

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Graeme wrote:
21 Sep 2020, 06:10
The nebula is is about 4,000 light years away and 15 light years across so is about 6 arcsec across, about 3 arcsec radius.
The nebula is about 4,000 light years away and 15 light years across so is about 12 arcmin across, about 6 arcmin radius.
Hello Graeme, and thank you, but ... what didn't you understand about "please don't get too technical on me, "?
Now I had to go look up "arcsec" on the internet and there are two of them!
I chose the first, because it looked easier!
An Arcsec is 1/60 of 1/60 of a degree, so if I took two extremely thin slivers of bamboo and put the ends close to my eye(1), then made an angle of (just realized to use arcmins instead of arcsecs, so "6 arcmins radius") 0.1 of a degree, that would define a cone which, if held steadily, would neatly enclose this nebula.
Right?
Mars is expected to rise to -2.6 in October this year.
And rise it does! From behind one of the twin water towers, the one with the non-flashing red light, Mars enters stage-left, as it were, and drifts across my nighttime sky. When I wake around one or two or three in the morning, there he is, glaring in my window, clearing a path for The Sun.
I see Orion (holding back the curtain, so to speak) and quite a few other stars.

I cannot see the Big Dipper that well, because Bonavista Town Council in its infinite wisdom has made the streets safe to walk at night with Sodium streetlights every twenty yards or so, and Danny's dad has installed a five-giga-watt floodlight that will help the neighbourhood cats see where they are going at all hours of the night.
That is, out here on the pointy-tip of a peninsula jutting into The Atlantic Ocean we suffer something awful from light pollution.

One of these days (hint, hint), someone is going to recommend to me a star chart that I can understand, something at the level of a four- or five-year old. I shall print it off on Tom's printer and then mark each star and constellation as I locate it, and then apply for a slightly higher-level star-chart suitable for a seven year old.

Ignore Argus's comment "When Scuttle has turned into an astrophoto forum, or something else, ". He is only jealous because I am so well advanced into turning Eileen's Lounge into a Gardening Forum, with a sub-forum "Cooking". Besides which, he is fully-occupied marking my Swedish homework exercise until Friday.


As far as your fears go ("I hope the Lounge doesn't mind me spamming"), that ought not to be very far to be about 0.833 of an arc-second as you will see if you compare my post count against yours. You have a long way to go before you get to the stage of relocating from Toronto (jet flights almost every day) to Bonavista ($50 taxi from St John's if the fog/snow is not too bad and you don't forget to hang a right at Clarenville).

And for once I agree with Bob: Please spam us all you want with such images, Graeme!

Cheers
Chris
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Graeme
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Re: The Cocoon Nebula

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HansV wrote:
21 Sep 2020, 07:04
The Andromeda galaxy is visible to the naked eye - its apparent magnitude is 3.44. It looks fuzzy without binoculars or a telescope.

If I may, the magnitude scale is useful to differentiate between stars as points of light but not so useful as an indication of apparent brightness of an object the size of the Andromeda Galaxy. The whole thing is the size of 6 full Moons and if the whole thing had a magnitude of 3.44 it would be easily visible and quite a thing to see! But that figure represents the light received from Andromeda across the whole of it's surface area and it is in fact only naked eye visible in very good dark sky viewing conditions. I can't see it from my back garden which is quite dark. (Bortle 5) Surface brightness is more useful.

Regards

Graeme
Last edited by Graeme on 21 Sep 2020, 13:56, edited 2 times in total.
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Graeme
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Re: The Cocoon Nebula

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ChrisGreaves wrote:
21 Sep 2020, 12:02
Hello Graeme, and thank you, but ... what didn't you understand about "please don't get too technical on me, "?
Now I had to go look up "arcsec" on the internet and there are two of them!
I chose the first, because it looked easier!
An Arcsec is 1/60 of 1/60 of a degree, so if I took two extremely thin slivers of bamboo and put the ends close to my eye(1), then made an angle of (just realized to use arcmins instead of arcsecs, so "6 arcmins radius") 0.1 of a degree, that would define a cone which, if held steadily, would neatly enclose this nebula.
Right?

That's my understanding, although I hadn't considered the bamboo option!

Too technical with respect to maths is, to be fair, is not an easy thing to judge in a place where the reader is quite likely to be a mathematical genius!

ChrisGreaves wrote:
21 Sep 2020, 12:02
I cannot see the Big Dipper that well, because Bonavista Town Council in its infinite wisdom has made the streets safe to walk at night with Sodium streetlights every twenty yards or so, ....

A moot point perhaps but I was talking about the bowl of Ursa Minor rather than Ursa Major. However, if you can't see the big dipper, you're unlikely to see the small one! Light pollution is a growing problem in all built up places now.

Regards

Graeme
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Re: The Cocoon Nebula

Post by LisaGreen »

Gorgeous!!!!

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Re: The Cocoon Nebula

Post by HansV »

I find that it's easiest to see the Andromeda galaxy if I look just to the side of it. I start at the Pegasus trapezium, then from the upper left corner two stars to the left, two up and then a bit to the right. Don't try to look at it directly...
This is in a dark area, of course. Not where I live in the center of town.
Best wishes,
Hans

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Graeme
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Re: The Cocoon Nebula

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HansV wrote:
21 Sep 2020, 14:28
I find that it's easiest to see the Andromeda galaxy if I look just to the side of it. I start at the Pegasus trapezium, then from the upper left corner two stars to the left, two up and then a bit to the right. Don't try to look at it directly...
This is in a dark area, of course. Not where I live in the center of town.

That's averted vision in action! Something to do with the location of the rods and cones in the back of the eye.
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