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-   -   Mercury's transit (https://www.mersenneforum.org/showthread.php?t=24856)

xilman 2019-11-11 19:07

Sic transit gloria Monday,
 
Completely clouded out.

Exactly what one should expect in this ${DEITY}-forsaken country.

Dr Sardonicus 2019-11-11 20:05

[QUOTE=xilman;530322]Completely clouded out.

Exactly what one should expect in this ${DEITY}-forsaken country.[/QUOTE]Edmond Halley had a similarly gloomy view of the weather on the island of St. Helena, where he spent two years observing the heavens. In [url=https://halleyslog.wordpress.com/2014/03/28/return-to-st-helena/]Return to St Helena[/url] we find[quote]In November 1677 Halley wrote to Jonas Moore that:
[indent]such hath been my ill fortune, that the Horizon of this Island is almost always covered with a Cloud, which sometimes for some weeks together hath hid the Stars from us, and when it is clear, is of so small continuance, that we cannot take any number of Observations at once; so that now, when I expected to be returning, I have not finished above half my intended work; and almost despair to accomplish what you ought to expect from me.[/indent][/quote]

He was, however, able to observe the transit of Mercury on 28 October 1677.

Spherical Cow 2019-11-11 22:47

1 Attachment(s)
[QUOTE=xilman;530322]Completely clouded out.

Exactly what one should expect in this ${DEITY}-forsaken country.[/QUOTE]

Partially clouded out here in desert, but the best pictures were the ones with the clouds, actually, as there were no interesting sunspots. Nor any uninteresting sunspots, even. Cellphone camera again, so I'm sure you'll see many higher resolution images on the internet.

Better than waiting until 2032.

Norm

LaurV 2019-11-12 02:47

[QUOTE=xilman;530322]Sic transit gloria Monday[/QUOTE]
Correct is: sic transit Gloria Gaynor. Or, in this case, sic transit gloria alien, aaa... sorry, mercurian...

[YOUTUBE]ybXrrTX3LuI[/YOUTUBE]

LaurV 2019-11-12 02:55

[QUOTE=Spherical Cow;530349] the best pictures were the ones with the clouds, [/QUOTE]
That photo is not good, because the sun has a black dot in the middle.... :cmd:
I somehow imagine some communist censor publishing it in a scientific magazine, or a newspaper, but not before fixing the inaccuracy of the film...

Now, joking apart, assuming I have an infinite-resolution of that photo, could I guess/calculate your exact location on earth, where the photo was taken, without knowing the time it was taken at? (In theory this would be possible, I think)

Spherical Cow 2019-11-12 12:56

[QUOTE=LaurV;530359]That photo is not good, because the sun has a black dot in the middle.... :cmd:
I somehow imagine some communist censor publishing it in a scientific magazine, or a newspaper, but not before fixing the inaccuracy of the film...

Now, joking apart, assuming I have an infinite-resolution of that photo, could I guess/calculate your exact location on earth, where the photo was taken, without knowing the time it was taken at? (In theory this would be possible, I think)[/QUOTE]

Hmmm. Interesting; I'll have to think that through- my first guess would have been that we would need to know the time to calculate the location on earth. Plus, we would probably have to make assumptions about distortion of the image. The optics are not likely perfectly aligned- this is a cellphone mounted tentatively over the eyepiece, with cellophane tape and rubber washers as spacers; a [URL="https://en.wikipedia.org/wiki/Rube_Goldberg"]"Rube Goldberg"[/URL] approach (. (Although the cellophane tape has been carefully calibrated...). Guess I better measure the solar image first, to see if its actually circular.

Norm

retina 2019-11-12 13:08

[QUOTE=LaurV;530359]Now, joking apart, assuming I have an infinite-resolution of that photo, could I guess/calculate your exact location on earth, where the photo was taken, without knowing the time it was taken at? (In theory this would be possible, I think)[/QUOTE]I think the best you could expect is to narrow it down to a line crossing the Earth. To pinpoint the precise position on the line you need the exact time. Fortunately the exif metadata does have the time (but it doesn't have the GPS coords), and assuming the time is suitably accurate then you could compute the position.

PhilF 2019-11-12 16:25

[QUOTE=LaurV;530359]That photo is not good, because the sun has a black dot in the middle.... :cmd:
I somehow imagine some communist censor publishing it in a scientific magazine, or a newspaper, but not before fixing the inaccuracy of the film...

Now, joking apart, assuming I have an infinite-resolution of that photo, could I guess/calculate your exact location on earth, where the photo was taken, without knowing the time it was taken at? (In theory this would be possible, I think)[/QUOTE]

Because of the principle of the diffraction of light, there isn't any such thing as infinite resolution.

xilman 2019-11-12 19:39

[QUOTE=PhilF;530387]Because of the principle of the diffraction of light, there isn't any such thing as infinite resolution.[/QUOTE]Are you sure about that?

I'm not.

PhilF 2019-11-12 20:31

[QUOTE=xilman;530392]Are you sure about that?

I'm not.[/QUOTE]

A good discussion of diffraction limit can be found here:

[url]https://books.google.com/books?id=1g_OBQAAQBAJ&pg=PA282&lpg=PA282&dq=lens+%22infinite+resolution%22&source=bl&ots=7NqAoSBuhc&sig=ACfU3U08Ba8Fja1j5wHyGoqdund3B7vJew&hl=en&sa=X&ved=2ahUKEwir2riSweXlAhVPqZ4KHWSqC6kQ6AEwDHoECAcQAQ#v=onepage&q=lens%20%22infinite%20resolution%22&f=false[/url]

bsquared 2019-11-12 20:56

Video from NASA's SDO:
[url]https://vimeo.com/372671661[/url]


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