Is Photo of a Crescent or a Full Moon?

[anonymous]

I was browsing the Cambridge gallery on this website and noticed that the moon in "King's Moon" is described in the alt text as being a "crescent moon".



But it's not a crescent -- it's a full moon in mid-eclipse. (No truly crescent moon gets wider than a half moon, as this one is.)

[McQ]

Thanks for that observation. I had always thought it looked different, but now that you point it out I can certainly see that this is not a normal gibbous moon at all.

Odd thing though is that it was taken on the 9th October 2005 (somewhere near 8 pm GMT), and I do not believe that was the time of an eclipse. Am I mistaken on this, or is the look a result of something altogether different? No idea. Or, maybe my exif information was incorrectly set and the date I am checking is not when the photo was taken . . .

[Nik_CanLady52]

The Eclipses for October of that year were on the 3rd "Annual Solar" and a "Partial Lunar" on the 17th according to my research.

I just want to say I am in awe of your images.

[shreds]

Interesting that someone else should notice this and comment, it had occurred to me some time ago that it was a clever PS effect to create a more vibrant shot? However, if this is not the case it is certainly unusual.

[McQ]

Well, to hopefully get to the bottom of this I am including a crop at 50% resolution of the region near the moon.



This is straight from the camera's RAW file, downsized to 50%, and with nothing but a 200%/0.2/0 unsharp mask for web viewing. The moon was produced without any photoshop effect, I can certainly attest to that. This close-up should shed some light on whether the moon is a partial moon or not. I have always noticed some weird atmospheric effects with the clouds near the moon though...

[xeliex]

It's so bright! It gives me a headache looking at it

[benedikt]

Are you sure you didn't take the picture in December? I thought it was around the time when the BBC recorded the carol service, thus the artificial light on the plodge.

[McQ]

Absolutely positive about the day/date, plus or minus 24 hours. I have other photos within this same shoot that help me pinpoint the day. This was taken about two months before the BBC was there for the filming.

On another note, the earlier poster got me thinking... After closer inspection of other photos taken that night (also including the moon), I now believe that the eclipse-like look was caused by (i) the length of the exposure and (ii) the very long focal length, which made the moon so large. This caused the bright region of the moon to appear more elongated than it would normally appear, and moved the location of the crescent edge so that it was in an eclipse-like, off-center location. I never originally thought this would be so pronounced.

Here's two photos from this same night taken within minutes of each other, but with very different exposures:


30 second exposure time (off-center, eclipse-like crescent position)


5 second exposure time (moon is circular and no longer looks eclipsed)

[shreds]

That makes sense and I can now see the almost straight/parallel lines as the moon has moved creating the elongated shape.

Certainly when I have done night shots in the past, the speed of the moon's movement has proved problematical if trying to expose for other detail.

Conundrum solved...thanks