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midtskogen
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Total Solar Eclipse 2017

28 Aug 2017 08:34

DoctorOfSpace wrote:
Source of the post Is it just my memory playing tricks or was it possible to see the Moon's face during totality?  

I think that's impossible, unless you look through a long tube blocking out the light of the corona and surrounding sky.
In Svalbard the disc appeared as the blackest thing I've ever seen.  Not so striking in Madras, probably because there was less contrast (white landscape in Svalbard, sun closer to the ground).
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28 Aug 2017 09:53

The last picture that I took with the filter on.  The lack of mirror lock-up is evident.  The mirror causes a vertical vibration, despite a 1/200 second exposure.
partial.jpg
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28 Aug 2017 10:10

DoctorOfSpace wrote:
Is it just my memory playing tricks or was it possible to see the Moon's face during totality?  

Possible; totality is about the same magnitude as a full moon, and afaik, it doesn't outshine the earthshine. Presumably, much like when the eclipse as seen from Earth doesn't seem to have much of an impact on solar brightness until a huge chunk of the sun is covered, the moons shadow as seen lunarside doesn't take up too much of the Earth's disk to significantly impact Earthshine. Afaik, anyway. :)
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midtskogen
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28 Aug 2017 10:40

PlutonianEmpire wrote:
Source of the post totality is about the same magnitude as a full moon, and afaik, it doesn't outshine the earthshine.

There is no earthshine if the Moon is full. :)  Half moon, or a gibbous Moon, however...  Then it greatly helps that the edge can be directly contrasted with a darker sky.

If it hadn't been for the bright corona, it might be possible to see features on the Moon despite the not so dark sky.  But contrasted against the corona I think you're out of luck.
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Watsisname
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28 Aug 2017 12:30

DoctorOfSpace wrote:
Source of the post Is it just my memory playing tricks or was it possible to see the Moon's face during totality?  

Yeah, I would be surprised.  I was remembering my conversation with Midtskogen on the old forum about how he commented that the Moon's disk appears pure black during totality, and sure enough that's what it looked to me.  Pure black surrounded by a thin perfect circle of brilliant light, threading outward into the corona.  For me the pure black disk of the Moon was expected, but not that thin shining circle (and did the rest of you have that impression of that circle or was it just me?), or how far the corona extended.

The Earthshine on the Moon should be brightest during a solar eclipse, and would be visible if that's all there was in the sky at totality, but I think the brightness of the corona right next to it tricks our eyes into setting it to black.
 
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28 Aug 2017 12:48

Watsisname wrote:
Source of the post For me the pure black disk of the Moon was expected, but not that thin shining circle (and did the rest of you have that impression of that circle or was it just me?)

You mean shining circle as in a solid ring and no details visible near the disk?  I also noticed that as different from the 2015 eclipse, and this is what I meant by describing the corona as somewhat "washed out".  I thought that it could be caused by the smoke layer above Madras, but it could be a feature of the corona on that particular day as well.
The extent of the corona took me by surprise in the 2015 eclipse as well.  Hard to tell which had the largest corona.  The 2017 corona wasn't strikingly large to me, but it doesn't mean that the 2015 corona was larger.  This time I knew what to expect.  In 1999 the corona was barely visible for a few seconds at my location during totality.
A lot of beautiful HDR images have been published after the eclipse, but I have yet to see an HDR video of the third contact (or second, but that's more tricky).  It shouldn't be too hard to make with the right gear.  With multiple cameras, that is.  It could be really near to see the Baily's beads and the diamond ring as an HDR video.  For this I think it'll be better to do it closer to the edge of the totality zone than the centre line, since the beads and diamond will be visible for a longer time near the edge.
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28 Aug 2017 13:26

Good to know memory is fallible, kinda thought so.
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Watsisname
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28 Aug 2017 15:47

midtskogen wrote:
Source of the post You mean shining circle as in a solid ring and no details visible near the disk?

I'm not sure.  In my memory it was pretty solid and much brighter than the rest of the inner corona, but in reality it may have had fine structure -- actually I would expect it to.  And in terms of thickness it was very thin -- just a few percent of the radius of the Sun, like the size of the ring of an almost-total annular eclipse.  Or about the same extent from the sun that the prominences reach.  I tried combining some shots from Harbinger and myself and adding in the ring to recreate what I remember in my mind's eye.  I think this is as close as I'll ever get.
Image
I had brought two pairs of binoculars to observe the Sun during totality, and set them on the roof of my car before the eclipse started so they would be quick to grab.  And, of course, when totality hit I was so overwhelmed I forgot to look through them...
 
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Total Solar Eclipse 2017

29 Aug 2017 16:47

Watsisname wrote:
midtskogen wrote:
Source of the post You mean shining circle as in a solid ring and no details visible near the disk?

I'm not sure.  In my memory it was pretty solid and much brighter than the rest of the inner corona, but in reality it may have had fine structure -- actually I would expect it to.  And in terms of thickness it was very thin -- just a few percent of the radius of the Sun, like the size of the ring of an almost-total annular eclipse.  Or about the same extent from the sun that the prominences reach.  I tried combining some shots from Harbinger and myself and adding in the ring to recreate what I remember in my mind's eye.  I think this is as close as I'll ever get.
Image
I had brought two pairs of binoculars to observe the Sun during totality, and set them on the roof of my car before the eclipse started so they would be quick to grab.  And, of course, when totality hit I was so overwhelmed I forgot to look through them...

haha well at least you didn't keep the lens cap on the lens ;-)
 
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29 Aug 2017 20:06

Yes, of all mistakes that could be made or things to forget, that was a pretty minor one.  

I remarked after the trip that there were countless things that could have gone wrong, but everything was perfect.  And I was hugely concerned with that ominous bank of smoke coming in after sunrise, to the point where I obsessed about the wind speed and direction (there were several flags within view to watch the wind with), and even considered driving out to try to get ahead of the smoke.  I'm very glad that I didn't -- that would have been a very big mistake.

Am I correct in observing that for all of us who were able to make it to the totality path (6 of us?), nobody was clouded out?
 
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29 Aug 2017 21:31

Watsisname wrote:
Source of the post Am I correct in observing that for all of us who were able to make it to the totality path (6 of us?), nobody was clouded out?

It seems like you are.
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midtskogen
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Total Solar Eclipse 2017

30 Aug 2017 01:35

An absolute must see:
https://vimeo.com/231484786
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Watsisname
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Total Solar Eclipse 2017

30 Aug 2017 02:45

Midtskogen:  Gorgeous video!  The beads and the chromosphere at that magnification are amazing.


Now that I have my own data to work with I decided to do a test of the Moon blackness illusion.  Here's the shot:  300mm ISO400, f/5.6, 1/100sec, RAW with a +3ev exposure boost.

► Show Spoiler


Took an average sample of pixels in a 30x30 square around the center of the Moon's disk, and then painted that color out to the edge of the image.  As usual with this illusion, the true equivalence in brightness between sky and moon occurs much closer to the Moon than initially expected.  I then drew in pixel values (RGB percentages).

► Show Spoiler


This shows the Moon is equivalent -- in this case not just in brightness but the color as well -- to the sky about 4 to 5 solar radii away, or just outside the visible corona.  Somehow the eye decides to call it pure black when it actually sees this, and the effect is also often present in photographs, though not as strongly.

Or another way to visualize it, using "by color select" after blurring the image, and choosing pixels within +/- 1 of the color of the Moon.
 
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Total Solar Eclipse 2017

30 Aug 2017 04:09

I have another "test" for pure blackness- many years ago I saw a total lunar eclipse that I read was influenced by a volcanic eruption and the moon looked like a black hole in the sky- darker than the background sky!  Can anyone find out how "black" this lunar eclipse was- its magnitude?  I was just a little child at the time and it was my second lunar eclipse- it occurred in late December 1982.  My first lunar eclipse that I had seen occurred in July 1981 and was one of the brightest (it was a bright orange)- so the contrast between the two was amazing!
 
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Total Solar Eclipse 2017

30 Aug 2017 05:15

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