An Accidental Lunar X

When I took this shot of the moon on 9 PM 18 May 2021 from my balcony in Hamilton, Ontario (with a Nikon CoolPix P950 at 2000 mm zoom) I was pretty happy with the detail along the terminator – the zone between sunlight and shadow. Lots of lovely craters, some clear enough to see central peaks. Contrast is important: when I took the photo the sky was still blue to the unaided eye. The moon is so bright that to photograph it for surface detail usually means tricking the camera to under-expose the shot; automatic camera settings are not designed for this kind of thing. I always shoot astronomical subjects with the camera on manual. This photo was taken at ISO 560, 1/150 sec, f 6.5, hand-held with on-camera image stabilization. Normally you should only try hand-held shots with the shutter speed at the reciprocal of focal length (for example, 1/500 of a second if the focal length is 500 mm), but the stabilization in this camera is very good.

A nice photo of the moon. taken with a Nikon Coolpix P950.

What I did’t notice until pointed out by John Gavreau of the Hamilton Amateur Astronomers is that I accidentally captured the famous Lunar X in the photograph.

The Lunar X is visible in the middle of this cropped frame.

The Lunar X is a transient feature caused by oblique sunlight falling on the rims of adjacent craters.

Clear skies!