May I ask
for colours - even on the Moon.
Aunt 1: The Moon is
Aunt 2: No the Moon is
Aunt 1: The Moon has the
color, moons should have!
(From "Skaermydsler" by
Gustav Wied, 1901)
Connoisseurs of Danish author and playwright, Gustav
Wied’s "Skaermydsler" (meaning something like
"Skirmishes" - “Tiffs” or
“Eternal small quarrels”) may recall Aunt 1 lecture Aunt
2 that "The Moon has the color, moons should have." But
is this entirely true? Folks as folks are mostly like
always ask for clarity and sharpness in lunar
photographs and then again for a little extra sharpness
and then once again for more sharpness. But what happens
with the colours of the Moon?
Picture taken on 24 April 2010 with an
old Olympus C-50Z 5MP compact camera
and a Tamron spotting scope (17.5X
magnification). Six images stacked in Registax
and post-processed in PhotoImpact.
look upon the Moon, glaring high in the night sky, we
see it mostly in grayscale and finer nuances are hard to
distinguish. On the other hand, when we see it closer to
the horizon, the blue light scatters more than the red
and green, while at the same time the light is dimmed by
the atmosphere and we see the moon in more "pleasant"
reddish and yellowish hues. And it is much easier to
distinguish the subtle nuances between different parts
of the lunar surface in this situation.
find a fine little discussion on the lunar colours in a
program for “Skirmishes” from Aalborg Theatre here:
http://www.aalborgteater.dk/Files/Bille ... ER_WEB.pdf
we reproduce these tones - although we cannot really see
them - with digital technology? The answer is a partial
“YES”. The obvious thing to do would be to use
High Dynamic Range (HDR) techniques directly,
but for several reasons HDR is not so suitable (or easy)
for lunar photography. HDR images of the moon usually
turn out rather blurred for a number of reasons. HDR is
very sensitive to the minute changes from image to image
due to field rotation, constant shifts in images due to
local variations in refraction (air turbulence) and
general shifts in image position on the sensor and the
consequential distortions (in particular when you apply
fixed tripod techniques).
But you may generate
a sensor- and scene-specific Camera Curve Profile
Function (in PhtoImpact called CCF-files) while
you produce an HDR image and such a CCF can actually be
used to amplify the nuances of levels in single
exposures. Over the years I have established a small
library of such profiles and in the initial image on
this page and in what follows I have used some profiles
based upon series of images recorded when the moon was
low in the sky and the differences in colour were thus,
accordingly, the more pronounced. There is no exact
science in this: One has to try out different profiles
on each occasion, and the aforementioned "opening image"
is probably "too tough a diet" for most. But here comes
a more "normal" example:
a number of individual exposures (here 6) in Registax:
Increase sharpness and make a crude adjustment of levels
(here in PhotoImpac) and make some, if so required,
clean-ups of hot pixels, chromatic aberration, etc.:
3.a. From hereon
then proceed with sharpening and contrast adjustments
one may also try to find a suitable camera Curve Profile
in one’s "library" and THEN you can get something like
.... and that was merely what I wanted to show.
shown here are based upon the same 6 single exposures
taken with an Olympus C-50Z 5 MP camera through a Tamron
350 mm catadioptric mirror tele lens with a 20 mm
eyepiece, (Tamron SP 350mm f/5.6, Model 06B + Tamron
TeleView wide-field adapter).
The general set-up is shown here. The resulting
focal length is 400 mm and the effective aperture is
about f/6. All pictures were taken at 1 / 50 second at
ISO 80. The pictures shown are full, un-cropped images.
All images shown on this page are scaled down here from
2560 pixels’ width to 1100 pixels - which of course
unfortunately does degrade the image resolution actually
achieved in the originals.
note: You do not strictly need to apply those CCF’s /
profiles. In principle you may achieve the same results
by playing around with curves and levels, but THAT would
be hard work to get reasonably right from time to time.