Isabel Williamson Lunar Observing Program

About the Isabel Williamson Lunar Observing Program

The Moon is by far the most detailed astronomical object to observe through a telescope and the comprehensive Isabel Williamson Lunar Observing Program (IWLOP) will guide you through a complete tour of our nearest neighbour's incredible surface. The program includes many outstanding craters, mountains, valleys, scarps, ridges, and more, not only showing you how they appear, but also describing the history of their formation over four billion years. The RASC Observing Committee created the IWLOP in 2006 as a certificate program for intermediate observers; since then, 18+ RASC members have earned their IWLOP certificates and many have provided constructive comments, leading to several minor revisions and corrections to date.

IWLOP guide (Revised 4nd Edition, 2019)

The IWLOP is an educational experience, including a detailed guide with key information about the lunar surface and how to observe it. The guide begins with an overview that outlines the required objectives for earning the certificate, and includes extra optional activities such as challenge objectives, lunar sketching, lunar astrophotography, craters with Canadian connections, and the Lunar 1000 Challenge. A detailed history of the Moon follows, including the various eras that have shaped its surface. Several types of lunar surface feature is described, along with their unique observable characteristics. The Foreword by David Levy is a testimonial to Isabel Williamson herself, a mentor to David and many other RASC observers, and for whom the program is named.

How to Obtain a Program Guide

Anyone may freely download the IWLOP guide (1 MB pdf). You will also need the IWLOP Logbook (1.8 MB) or some alternate means of logging observations to the same level of detail.  (Feel free to print these materials for personal use, and please note that they are copyrighted by the Royal Astronomical Society of Canada.)

RASC Isabel Williamson Lunar Observing Program Certificate

RASC members who have have completed the required objectives of the IWLOP may apply for a certificate and pin as follows: Download and complete the PDF application form below. Extra distinction can be earned for obseving at least 100 challenge objects.

Present your application and observing records to your Centre Executive for validation. Two executive signatures are required on the application form, which should then be sent to the Observing Chair. Alternatively, any member (especially a National Member) may send an application and a suitable copy of observing records directly to the Observing Chair (by arrangement, files maybe sent electronically in a mutually agreeable format). Sending an original logbook is acceptable, at the applicant's risk, but not recommended!
Use this generic form for all applications (except the Explore the Universe program, which has one suited for both RASC members and non-members). The form has pull-down menus for language of choice for the Certificate, plus to choose Centre Affiliation or to select "National or Unattached."

Contact the Observing Committee chair


The official atlas of the IWLOP is Rükl's Atlas of the Moon, now out of print, but available on the used market (check your public library for a copy). We offer this online substitute, based on the Rükl atlas: Hypertextual Moon Atlas

Charles Woods' The Modern Moon: A Personal View is an excellent resource for the certificate. 

Woods and Collins' The 21st Century Atlas of the Moon

More on Isabel K. Williamson JRASC 94, 201 (2000)

Find out details about the Isabel Williamson Lunar Observing program here.