Starship Asterisk*

Spot the Moon

Explanation: Where's the full Moon? Somewhere in this image, the Earth's Moon is hiding. The entire Moon is visible, in its completely full phase, in plain sight. Even the photographer's keen eye couldn't find it even though he knew exactly where to look -- only the long exposure of his camera picked it up -- barely. Although by now you might be congratulating yourself on finding it, why was it so difficult to see? For one reason, this photograph was taken during the total lunar eclipse last month, when the Earth's shadow made the Moon much dimmer than a normal full Moon. For another, the image, taken in Colorado, USA, was captured just 12 minutes before sunrise. With the Moon on the exact opposite side of the sky from the Sun, this meant that the Sun was just below the horizon, but still slightly illuminating the sky. Last, as the Moon was only about two degrees above the horizon, the large volume of air between the camera and the horizon scattered a lot of light away from the background Moon. Twelve minutes after this image was acquired the Sun peeked over the horizon and the Moon set.

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Twelve minute exposure yet the mountainside is poorly visible tells you a lot about the foggy air. Nearby hillside is the only part of the image that tells you the camera was working properly.

I found it:

http://i44.tinypic.com/5now84.jpg

bactame wrote:Twelve minute exposure yet the mountainside is poorly visible tells you a lot about the foggy air. Nearby hillside is the only part of the image that tells you the camera was working properly.

It was a 1/10 second exposure. The more distant mountains are distorted by ground air effects.
What's interesting is that I took this image 10 minutes before sunrise (2 minutes later than today's image), also in Colorado. At this point, I could still easily see the Moon with my eyes, and you can see that it's much more obvious in the picture, less than one degree above the mountains. I assume I simply had clearer air at my location than Jimmy did at his. Less scatter of the dawn light, and therefore better contrast.

It also looks like the camera was focused on the near field and not infinity so the edge of the moon in indistinct so harder to see.

try averted vision

I had to give a second look; and there it was!

It popped right into view for me after I relaxed my eyes and stopped scanning the picture.

Yep.

Chris Peterson wrote:What's interesting is that I took this image 10 minutes before sunrise (2 minutes later than today's image), also in Colorado.

What was the exact time of your picture?

Although probably not a significant contributor, Jimmy's location should be considered. If he was further west (e.g. Steamboat Sprinngs where he teaches), sunrise for him was about 11 minutes later than at Elevenmile Canyon Resevoir. Conceivably, his picture was taken taken 5min to 10min deeper into the eclipse (totality started at 7:06 MT) which would exacerbate the low contrast problem.
I can't see that this alone explains the contrast difference, but given the low altitude and level of twighlight involved, it seemed that location and timing details are also worth mentioning.

I saw the moon in the picture within the minute the picture pulled up!

alter-ego wrote:What was the exact time of your picture?

Although probably not a significant contributor, Jimmy's location should be considered. If he was further west (e.g. Steamboat Sprinngs where he teaches), sunrise for him was about 11 minutes later than at Elevenmile Canyon Resevoir. Conceivably, his picture was taken taken 5min to 10min deeper into the eclipse (totality started at 7:06 MT) which would exacerbate the low contrast problem.

My image was taken at UT 13:59. Sunrise at my location was UT 14:09.

The fact that he was a little farther into the eclipse is probably significant, since the sliver of illuminated Moon was reduced... perhaps to nothing in his case. If he was in Steamboat, the air there is typically a lot wetter than here, so that is probably also significant in considering contrast.

@ StACase Your straightforward and simple posting bested our revered solons==including my hero Chris P. Thanx .

Fascinating!