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DoctorOfSpace
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03 Sep 2017 11:06

Quite a nice composite Watsisname
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03 Sep 2017 11:37

midtskogen wrote:
Great job!  This is a very good match with what I saw.

I've made a 50x50 cm print of my composite photo and put it on the wall. And the protuberances came out very nicely on that print, much better than what I got on my monitor!

Were the prominences a pink color like in some of the photographs I saw?
 
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03 Sep 2017 12:07

A-L-E-X wrote:
Source of the post Were the prominences a pink color like in some of the photographs I saw?

They were very hard to see with the naked eye, if not impossible.  Through my scope they looked closer to red.
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03 Sep 2017 12:21

DoctorOfSpace wrote:
A-L-E-X wrote:
Source of the post Were the prominences a pink color like in some of the photographs I saw?

They were very hard to see with the naked eye, if not impossible.  Through my scope they looked closer to red.

I saw them pink in some pictures, figured the reddish or pinkish color was a function of them being cooler than the surface of the sun.  Do you think they were really red or was that some kind of illusion?  Also, what kind of solar filter do you use?
 
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03 Sep 2017 12:38

A-L-E-X wrote:
Source of the post Were the prominences a pink color like in some of the photographs I saw?

Pink seems right to me.
DoctorOfSpace wrote:
Source of the post They were very hard to see with the naked eye, if not impossible.

Really?  I found them easy to see, and I didn't even wear my lenses (i only have some astigmatism, though, so perhaps I saw twice as many protuberances :)
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03 Sep 2017 14:44

midtskogen wrote:
Source of the post Really?  I found them easy to see, and I didn't even wear my lenses (i only have some astigmatism, though, so perhaps I saw twice as many protuberances

Maybe.  I don't recall being able to see them with my unaided eyes, though I wasn't really looking for them.  I did see them when I looked through my camera though.
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03 Sep 2017 14:47

I could see them clearly on camera but only barely with the eye.  I also have some astigmatism.  It was much easier to see the chromosphere for a few seconds after C2.  Both appeared pinkish.

The color comes from H-alpha emission (actually the Balmer series, where the H-alpha line is red and combined with the blue/violet lines becomes more pinkish), since that part of the Sun's atmosphere is thin and ionized.  The temperature is a bit higher than the photosphere beneath it (from about 5,000 to 8,000 Kelvin), but much colder and denser than the surrounding corona which is millions of Kelvins.

You can see approximately the same color from a hydrogen discharge tube:

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03 Sep 2017 18:14

Thanks, Wat, that kind of reminds me of the color we see from H-alpha emitting nebula (though it's a bit pinker since as you say it's mixed with B/V.)
 
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03 Sep 2017 18:47

Watsisname wrote:
Source of the post I also have some astigmatism

I do not.  I wonder if this is a contributing factor to what you and midtskogen saw.
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03 Sep 2017 21:18

I don't think it would be.  Astigmatism causes a fainter double image in dim light, but it doesn't change the color.  But at any rate the prominences were pretty much right at the limit of my ability to see, even the largest one at the western limb.  I doubt I'd have noticed them at all if I hadn't known where they were from the camera display.  

Could you see the thin red/pink arc of chromosphere in the few seconds after C2 or before C3?  To me that was much more apparent to the eye.

Added: It could also depend on when you look, as the prominences on the western side will be more exposed near the end of totality while the eastern side gets more covered.
 
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03 Sep 2017 22:06

I think it makes a big difference to know what to look for.  Astigmatism doesn't help, but may not make it harder to see it in this case, as it simply (at least in my case) causes things to appear double, but still perfectly sharp (though some stuff with odd angles and spacings might appear blurred).  It's certainly not the case that these things are hard to see in the general case.  In Svalbard I did not look through a telescope during the eclipse at all, just briefly through a camera with a 200mm zoom lens, but I know for sure that I saw everything with the naked eye before I looked through any lens.  In Madras I did take a couple of shots with my 1000 mm lens shortly after the beginning of totality, which might have helped when watching with the naked eye afterwards.

EDIT: are prominences and protuberances used with exactly the same meaning in the English terminology, the former more common?
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03 Sep 2017 22:37

Actually astigmatism might HELP.  Since it causes you to see double, in effect you see something twice- and it becomes easier to notice.
 
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03 Sep 2017 22:40

Mid, how do you carry such heavy lenses around?  I bought  a big lens and then returned it right away because it was simply too heavy- I do not do well with anything over 200mm.  Rather do digiscoping with a telescope.
 
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03 Sep 2017 23:18

midtskogen wrote:
Source of the post EDIT: are prominences and protuberances used with exactly the same meaning in the English terminology, the former more common?

I think they're used with the same meaning.  https://en.wikipedia.org/wiki/Solar_prominence  
Unless protuberance could apply to anything that sticks out from the Sun, in which case that could include spicules, but those are too small to see with the unaided eye.
 
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03 Sep 2017 23:44

A-L-E-X wrote:
Source of the post Actually astigmatism might HELP.  Since it causes you to see double, in effect you see something twice- and it becomes easier to notice.

Well, there's no more light entering the eye, and things depend a lot on contrast.
A-L-E-X wrote:
Source of the post Mid, how do you carry such heavy lenses around?  I bought  a big lens and then returned it right away because it was simply too heavy- I do not do well with anything over 200mm.  Rather do digiscoping with a telescope.

When I fly to SFO I usually do it without checked-in luggage for convenience, but since I obviously wanted to bring some stuff with me this time, I simply filled up a suitcase with gear till it weighed slightly above 20 kg (I think my ticket allowed 2x23 kg, but I didn't want to drag two suitcases).  The heavy stuff was tripods.  The 1000 mm (and I also had a 1.6x teleconverter which together with the DSLR's sensor size gave 2400 mm effectively, perfect for having the sun fill the entire frame) is light and small, because it's a reflex lens (like Newtonian telescopes).  The lens weighs 1.9 kg, but probably around 2.5-3 kg with the case.  Some stats here.

You can see the lens at 4:35 in my video.  It's even more compact than most telescopes.
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