- Now, dear Danny, your head is always on the moon. It seems that you are a motivated telescopic observer of the full moon. Why?

- Well, Earth's moon is still the most "small telescope friendly" extraterrestrial object to observe. It's not like the rather vague deepsky objects and comets. Planets such as Jupiter, Saturn, and Mars always look a bit too small, they require large telescopes. Of Venus there's not much to see, especially when the crescent of this planet shows its largest angular diameter. There's only this very thin bright looking arc. That's why I observe the moon, especially the full moon because you have much more moon than during first quarter or last quarter moon, or during waxing and waning crescent moon.

- I see. Is it true that you always wanted a huge printed version of a high resolution photograph of the full moon? Some sort of poster or mural the size of a wall in a living room, to look at it whenever a "daydreaming moment" is going on?

- Oh yes! I always knew there was a lot of odd looking surface details up there, especially when the shadows were absent, and only the bright and dark albedo features were visible. A totally different moon!

- Not many people want to observe the full moon because it's too bright. You are one of the few who don't care about the full moon's brightness.

- Not at all. If the full moon's too bright to observe, try to illuminate the interior of your observer's dome, or observer's room, as much as possible. Pure white artificial lightsources shining on white painted interior walls could create daylight circumstances to avoid the blinding effect of the full moon's disc. The color sensitivity of the observing eye is at 100 percent during the day, in daylight, not at night. This way it is possible to detect subtle color differences on the moon's surface, such as the remarkable color contrast at Mare Serenitatis and Mare Tranquillitatis, or the mustard-colored Wood's Spot at the Aristarchus plateau. When you use a grey filter on the eyepiece of your telescope, to darken the bright moon and to avoid the additional illumination by artificial white lightsources, the color sensitivity of your observing eye is not what it should be, and gone are the subtle colors on the moon.

- Now I understand why your head is always on the moon. Do you really know what's going on at your home planet called Earth? Do people say things like "Earth to Danny" or "Earth calling Danny"?

- Sometimes. I do listen to the radio, to hear the daily news. I don't watch television, or perhaps one hour in a month, to see if the apparatus is still working. And when it does, there's not much interesting to watch. Frankly, television of today looks very much like a reverberation or some sort of revival of the dark and cruel medieval ages. The serenity and tranquillity of lunar observing doesn't exist on television. It would be very interesting if amateur astronomers and astrophotographers get 'Carte Blanche' to show their interesting techniques, especially 'on the spot', while they observe or make photographs^[2] of deepsky objects, contrast-colored binary stars, red colored cool carbon stars, planets, comets, the sun, and the moon! Alas, all of these subjects seem to be 'too difficult to comprehend'. As if astronomy and amateur astronomy are not-from-this-world. People always see it as mathematics, something for 'Einstein'-esque professors and brave 'goody' pupils at school, the so-called 'little professors'.

- Certainly, you are not an 'Einstein'-esque professor or brave 'goody' pupil, but... are you aware of the fact that you are a very strange being? A curiosity?

- You must know, I am not a serial product.

NOTES:

The visibility of subtle colors on the moon was described by Valdemar Axel Firsoff in this book The Old Moon and the New (Sidgwick & Jackson, London, 1969), in which Mr. Firsoff mentioned the absolute colorless appearance of the observed moon as seen through the small windows of Apollo 8's command module (Jim Lovell's "Plaster of Paris" look of the moon's surface, "essentially grey" as he described it). The interior of the command module was not illuminated as in a sunlit white painted room, and the color sensitivity of the eyes of the astronauts was not adapted to daylight circumstances. The result: a much too bright looking greyish moon.

Telescopic observers who want to explore the full moon must try to get The Clementine Atlas of the Moon by Ben Bussey and Paul D. Spudis, because in this photographic atlas all lunar surface formations at the equatorial zones (and also north and south of these zones) are depicted without shadows, very much the same way as they show up while looking at the full moon. Very interesting! Thus... only the bright and dark albedo features are seen.

For those who want to see an online version of the shadowless full moon, it is recommendable to explore the LROC site (Lunar Reconnaissance Orbiter Camera), because in this site it is possible to see a HUUUUGE full moon (full of minute details), and... also a color version of it which shows the subtle colorations at, for example, the tiny satellite craterlet Beaumont L in Mare Nectaris, or the odd D-shaped formation Ina at Lacus Felicitatis. Very curious! Ina looks blue! Anyway, the LROC site is an interesting experience!

The appearance of a bright white looking young bowl-shaped crater such as satellite crater Hipparchus C near the centre of the full moon looks very much like a staring eye, with white iris and black pupil. Comparable with the staring eyes of the possessed children in Wolf Rilla's Village of the Damned (1960). The inner slopes of such craters show very high albedo values, while the flat floors show a low albedo. The contrast effect of the bright inner slopes and the dark floors of such young craters is remarkable.

Probably not included in the list of entoptic phenomena, and also not described or mentioned in encyclopedia or scientific books and articles about optical phenomena, is the appearance of a vague red or dark red colored arc at the centre of vision when one is looking at a black background and at an angle of less than 45 degrees away from a bright pointlike white lightsource. The angular diameter of this arc is comparable with five lunar discs in a row. This arc looks very much like a small version of the Circumzenithal arc, although it is not a halo phenomenon, it is an entoptic phenomenon, probably related to Maxwell's spot at the Fovea centralis and perhaps also to Haidinger's brush. When one is capable of observing this vague red or dark red arc-shaped appearance, one could also see the 'network' of silhouetted blood vessels all over the field of view. A remarkable concentration of blood vessels is noticeable at the location of the Blind spot, very much looking like a road map of a large city, or a cobweb. As far as I know, this entoptic phenomenon is nowhere else described or mentioned, and I wonder if the Optical Society of America (OSA) (nowadays Optica), or The Lancet, or Nature, are aware of the existence of this phenomenon. It is easy to observe (all you need is a bright pointlike white lightsource surrounded by pitch black background). Needless to say that, when our scientific explorer and observer Danny J. Caes discovered this entoptic phenomenon in 1978, age 14, no one would have listen to him because it sounded too bizarre and "far away", something which was not comparable with terrestrial topics such as soccer or the Roman empire (bright pupils in those days were supposed to know everything about the Roman empire, not about entoptic phenomena).^[3]

Maxwell's spot is best observed on a purple or violet background. The centre of vision shows a deep pink colored circle, a bit brighter than the purple background.

To see these entoptic phenomena (Caes Arc, Maxwell's Spot, Haidinger's Brush), and also the halo phenomenon Circumzenithal Arc, no such substances as hallucinogens are involved! Nothing of this kind! Much too often one would hear: Dear friend, what on (or off) earth did you took to see such odd things like this? Frustrating! These are entoptic and optic phenomena, things which everyone of us could see. Another example: when the primary and secondary rainbows appear in a shower of rain, illuminated by the sun, and everybody is observing these two spectral colored arcs, that doesn't mean that all of them took hallucinogens. These are real optical phenomena, not some sort of non-existing ghost images created by a substance which is capable of changing some functions of the visual section in the brain.

If Jan Evangelista Purkyně was still among us, he would have told us that he also knew about this curious appearance of the vague red or dark red colored arc near a white pointlike lightsource.

Imagine: a waiting-room in a doctor's practice. The walls in this room show the whole collection of the Apollo program's Hasselblad photographs, depicted as tiny images the size of, say, little squares of 4 by 4 centimetres. I think such an overview of NASA's photographs could be the source of much interest and thoughts. Patients could feel much more positivism and motivation to explore all aspects of, for example, manned spaceflight and science. IMPORTANT: just the collection of photographs, no descriptions whatsoever. As an artwork for all ages (youngsters, adults, and elderly people), to avoid the sense of being at school.

For those who listen to the music of Philip Glass and his ensemble, aim your ears at the piece Façades from the album Glassworks. Take a simultaneous look at the black-and-white Hasselblad photographs made during the mission of Apollo 15, especially those which show the distant Mons Hadley and the Swann Range in Montes Apenninus, and also Mons Hadley delta and Rima Hadley, and feel the overwhelming wistfulness and the powerful sense of 'afterthoughts', and also the questions "How was it possible in those days to get to the moon and back?" and "How did they do that?"

Rand McNally's greenish colored (and rather huge) map of the moon's near side contains several names for surface formations which were not accepted by the International Astronomical Union (IAU). Rand McNally's moonmap also appeared in Patrick Moore's Atlas of the Universe (1970 / 1983). The names which were not accepted by the IAU are:

*Andreus Hills, north of Mare Humorum, east of Gassendi, and west of NASA's The Helmet (with the hillock Herigonius eta in or on it).

*Golubiz Cluster, a group of hills and hillocks between Campanus and Kies, at the most southwestern section of Mare Nubium. The name Golubiz Cluster was not included on the moonmap in Patrick Moore's Atlas of the Universe (1983).

*Leon Hills, the system of oblong and curved hills officially known as Wichmann R (the remains of an almost completely vanished crater), north of crater Wichmann in Oceanus Procellarum.

*Loró Basin, west-southwest of Airy and southeast of satellite crater Parrot G, contains a swirl pattern which is observable during full moon.

*Lothrop Hills, southwest of Euler at the southwestern section of Mare Imbrium, also called The Euler Group.

*Mishqui Basin, south of Mare Crisium.

*Mitika Peak, hillock Jansen alpha, southwest of Cajal in Mare Tranquillitatis.

*Morotcha, at the northern rim of Mare Vaporum. The most mysterious one of these names. No specific surface formation up there, there's only... the northern rim of Mare Vaporum.

Now, if someone of you dear readers and connoisseurs of lunar cartography and nomenclature know the reason and the origin of these strange names, please let us know!

Something for the musical ears of the connoisseurs of the Apollo program and the moon. Aim them (your ears) at Klaus Schulze's piece Moogetique from the album Body Love Volume 2, and think about the astronauts in orbit around the moon, and how they observed the light-bluish colored earthshine on the moon's nocturnal western regions, such as the dimly and ghostly lit raycrater Copernicus (one of NASA's proposed landing sites). The piano parts with delay effect let us 'feel' some sort of presence of all the people after whom many of the larger craters are named. As if they are residents on the moon. One could wonder if some (or all of) the astronauts also felt something like this. I know, all of this is not something to describe in an online encyclopedia, but... (let us remember that we are human, not robots).