I would always like to label our Moon “La Luna Che Non C’e.  It simply means, the Moon that is not there! All too often our very own Moon is the subject of neglect, of non-interest, of boredom due to its “unchanging” face.  Due to its proximity and seemingly permanent stature in the sky (it will never get lost), it is almost always taken for granted, reserved for nights when all other celestial objects are exhausted, and a piece to “kill” time. I am indeed too young to forget, that the Moon was my FIRST celestial object to be pointed at by my Bushnell 60mm refractor!  It was my first peek to another world, when I confused the grand play of light and shadow of its mountains to some optical defect!  It’s the Moon that thought me how to ‘interpret’ visions from the eyepiece, apart from color images visible in television and magazines.

Any veteran observer would not dismiss the Moon as having an “unchanging face” .  Libration has always been the cause of excitement, when at certain moments the Moon will tilt a bit to reveal some hidden features on its edge. For starters, Charles Wood’s Lunar 100 recently published in Sky and Telescope magazines is the way to go.  Wood’s package is almost  ever complete, even up to intermediates.  I am not a lunar expert, so I cannot make a fair comparison of various sources pertaining to the Moon.

It was the summer of 2001 when I heard Albert Lim’s (of Questar Incorporated, Singapore) personal recommendation of Westfall’s Atlas of the Lunar Terminator.  Sky and Telescope catalog for that year listed several books for the Moon, but he handpicked Westfall’s as one of his favorites. Albert himself was the co-author of their upcoming book (with fellow Singaporeans) due to publish the following year by Cambridge, another lunar book.

Trying to heal this lunar-neglect guilt, I ordered myself a copy, not cheap though (U$39.50)!  The spring of 2003 when I spend my time in bed nursing a fractured heel bone gave me fair time to goover the book in depth.  I judged Westfall’s images, as fair, albeit the incredible effort I realized spent on imaging the Moon’s terminator every given colongitude.  The images were actually far from excellent, perhaps a victim of premature CCD technology where the pictures were blurred and pixelized enough not to be sharp.  Today’s ordinary digital cameras can do better than that.

Nevertheless, Dr. Westfall’s has imparted to the reader a better understanding of the Moon and its features. He expertly dealt on the history and chronology of events arising from the formation of landform features. This gives the reader a running story in his/her mind how old or young were some of these features. The stark contrast of shadow play on the terminator is its main emphasis.  The terminator is the dividing line that separates the Moon’s day and night.  Shadow is the reason why we see lunar features (remember seeing nothing on a Full Moon?), the region of the terminator is what breathes life into lunar mountains, craters, hills by  showing both the light and dark sides at the same time.  In a sense, the terminator may be the best way/time/part to study a certain lunar feature.

The book is mainly an atlas, as the title says, of all visible features along the terminator.  An effort to make it the most intensely studied, intensely labeled atlas, two to three pages are needed to show the whole terminator, for northern and southern side.  Forty seven illumination corresponding to its proper colongitude are presented, with an increment of about 5 to 6 degrees colongitude  or a difference of 12 hours.  The increment is quite big, rarely will one zero-in on the exact colongitude the book presents.  Accompanying the map and its labels is a descriptive note, pushing further for more lunar stories.

What I especially like is the almanac provided for a lunar observation program, in the appendix contains table of lunar ephemeris from 2000 to 2010. Take note that this book will deal only with features visible in the (or very near) terminator, it will not show you anything further.  You must wait for your “favorite” feature to come close to the terminator, and you also learn to realize the  feature’s colongitude reading.