We have a winner! Geminga it is.

__________________
Forming opinions as we speak

Can you give us a link to where the luminosity and magnitude are discussed?

I'll work on a question ... and try to get it into the proper ballpark difficulty-wise.

OK ... this should be easier. About what day of the year was this photo taken? There might be two possible dates and +/-7 days would be a reasonable error range.

http://www.astro.ufl.edu/~oliver/Sundog.jpg

Nice sundog! I'll assume the sun is about 23 deg. above (and your about 23 deg. below ), so how about December 25th with everyone wearing their red Christmas coats.

__________________
Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

You have the location correct (I think) but you do not need to 'assume' the altitude of the sun ... your date is not correct.

The image seems to have been taken from a wide angle lens. If so, the sun is higher than one might think.

Hmmmm...because we can see people in the sun's shadow, then a partial eclipse may be underway. Otherwise, I see no other clue unless the tire track convergence angles will help calculate which lens was used to produce a solar altitude (which may or may not lead to the answer).

__________________
Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

That photo is a fake...the shadows of the people standing near the domed structure are pointed to our left while the person walking has a shadow pointing to the right. This was done on a sound stage with multiple light sources and the big thing in the "sky" is a photoshopped artifact made to look like the sun with a couple of sundogs.

On a serious note, what an excellent picture to be used on the conspiracy forums to debunk the shadow argument since the single light source is so perfectly obvious.

As to the quiz, I'm going to guess March 15 for no other reason then it's the first date that popped into my head

(edit to add) Some googling tells me that picture was taken at the South Pole so the sun angle would be 23 degrees.

__________________
I was just sitting here contemplating the immortal words of Socrates who said, "I drank what?"

"Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot." --Carl Sagan "Pale Blue Dot"

Bludgeoning helps. Consider yourself inducted into the local Brute Squad.

__________________
Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

I found this picture of the South Pole station on google which shows almost the exact same thing stating the picture was taken in November, so your estimate should be close.

__________________
I was just sitting here contemplating the immortal words of Socrates who said, "I drank what?"

"Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot." --Carl Sagan "Pale Blue Dot"

Hm, how about Thanksgiving day?

__________________
I was just sitting here contemplating the immortal words of Socrates who said, "I drank what?"

"Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot." --Carl Sagan "Pale Blue Dot"

Sorry to be technical

"Geminga was the first example of an unidentified gamma-ray source, a source which could not be associated with any objects known at other wavelength. It was first detected as a significant excess of gamma-rays over the expected background of diffuse Galactic emission, by the SAS-2 satellite (Fictel et al. 1975)"

thats more than a decade...

The point here seems to be that the circle linking the two sundogs almost exactly touches the horizon. Since it is a so-called 22 degree halo, the Sun is approx. 11° above the local horizon.

Now if this is South pole station, which it seems to be, there are two dates on which the Sun ha that elevation:

22 October and
20 February.

I'd prefer the first date, as that would be a nice birthday present for me.

And, kelfazin, thanks for the South Pole tip!

__________________
Non sunt multiplicanda entia praeter necessitatem.

How did I miss that after stating how nice his sun dog appeared? However, I believe the 22 degrees is the angle from the sun to the dog, so perhaps mid December or early January.

[Added: I suppose a date should be stated.... on or about December 15th or January 1st.]

__________________
Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

yes but your link states it's a 22 degree radius, which would put the sun 22-23 degrees off the horizon.

__________________
I was just sitting here contemplating the immortal words of Socrates who said, "I drank what?"

"Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot." --Carl Sagan "Pale Blue Dot"

Ok so sunrise at the south pole station begins around Sept, 23, winter solstice (noon?) is around Dec 22, and sunset starts around March 21. Since IMO said Dec 25 (+/- 7 days) was wrong that rules out the winter solstice.

Other interesting dates are the arrival of Roald Amundsen on Dec 14th and Robert Scott on Jan 18 (and the namesakes of th Amundsen-Scott South Pole Station) so the picture could be one of those dates as well

__________________
I was just sitting here contemplating the immortal words of Socrates who said, "I drank what?"

"Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot." --Carl Sagan "Pale Blue Dot"

Oh dear...

__________________
Non sunt multiplicanda entia praeter necessitatem.

I'm starting to think the picture can't be in January. Looking at the picture in Wiki the shadows are pointing to the other side of the dome so IMO's picture must be before Dec 22, which kind of makes me feel stronger about my Thanksgiving guess.

__________________
I was just sitting here contemplating the immortal words of Socrates who said, "I drank what?"

"Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot." --Carl Sagan "Pale Blue Dot"

It must be on or about the solstice. The altitude variation between days varies as the cosine of the days (~ 1 deg. per day) with the winter solstice = 0 deg. So, a 10 day difference either side of the solstice will only alter the altitude by < 2% (< 0.5 deg).

__________________
Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Somehow I know how you feel. Yet, you did find the key to unlock this puzzle, so you deserve to win it; start bludgeoning.

__________________
Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.