The Lunar X
This is the full-frame
image as it came from the camera on
March 3, 2009.
It's a 3888 x
2592 pixel array that was reduced to 800 x 533 for this web page.
No other processing was applied.
It was taken at 6:26 pm EST from Maple Shade, NJ, with a Canon 40D digital SLR at the
480 mm prime focus of a
William Optics 80 mm, f/6 apo refractor on a fixed tripod.
Manually exposed 1/320 second at ISO 400 with daylight white balance. Scroll down to zoom in on the "X".
For an nice page on this feature, see Jerry Lodriguss' page at
Catching the Light.
His picture was was the
APOD for March 11, 2009.
here's an RASC article about the Lunar X.
This is the same image
cropped to 1000 x 900, then spread to the same width as the picture
above. The "X" is visible on the terminator, about one-third of the way
from the bottom-left (south) to the upper-right (north). Mouseover
for label. Scroll down to
The is same image again,
but cropped to 300 x 300 and spread to 75% of the width of the images
above. The "X" is self-evident just left of center. Visually, the "X"
could also be located with the 80 mm scope and a 40 mm eyepiece (12x), but it
showed well with my 16 mm Nagler (30x) and 10 mm Radian (48x) eyepieces.
I could also spot it with 16x70 Fujinon binoculars (after bracing
them against a telephone pole).
The Lunar X
Here's a single frame
snapshot of the gibbous moon taken at 10:46 pm EDT on
May 24, 2018,
with a Canon 7D Mk II digital SLR camera at the 910 mm prime focus of a
Stellarvue 130 mm, f/7 apo refractor. It was exposed 1/1000 second at
ISO 400, then converted to monochrome and cropped to about a third of
the sensor's area yielding a field about 0.6° square. I noticed that
when examined closely, the Lunar X
was visible, although not nearly as prominent as when it appears as a
highlight at the terminator. Mouseover for a label.
Here's an enlarging crop
of the image above to better show the "X" (mouseover for a label).
Unfortunately, as of this supplementary addition to the Lunar X page on
15-February-2021, I do not have ready access to the original image for a
better cropped view (as opposed to this cropping of an already-cropped
and resized image, although the 130 mm Stellarvue apo refractor provided
enough detail to endure it reasonably well).