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How I (re) Discovered the Moon

By David posted 10-03-2022 07:55

  

by Dave Chapman (RASC Halifax Centre)


https://linktr.ee/DaveChapman


During the International Year of Astronomy 2009, I discovered the Moon. Of course, it was there all along, and other people found it long before me.  I had even observed the Moon before, but it had been a long, long time. Let’s say I had a “moment of personal discovery” involving the Moon.


Why don’t we start from the beginning? When I was a boy, just getting interested in astronomy, the Moon was one of the first objects I observed through a telescope. On my 10thbirthday, on July 21, 1963, I received as gifts a 60 mm Tasco refractor and Patrick Moore’s “The Amateur Astronomer.” Three days later I made my first entry into my astronomy observing log, which I still have: page one contains a list of lunar maria and large craters that I observed that night and the following nights, including The Sea of Crises, Langrenus, Hipparchus, and the Marsh of Putrefaction. I sketched the Moon on September 29 of that year and continued to observe and sketch the Moon off and on for 5 years. The first Eclipse of the Moon I observed and recorded took on December 18, 1964, a bone-chilling winter night in Winnipeg, Manitoba.


I sometimes wonder if my interest in the Moon dwindled with the Apollo 11 landing in 1969 and Neil Armstrong’s first steps on my 16th birthday. Why observe the Moon when people go there now? Another possibility was that I started getting interested in observing Deep Sky objects, requiring dark skies, and I began to shun the Moon, as others do today. By 1968, I was in Ottawa and caught up in the Observers Group of the RASC Ottawa Centre. The Deep Sky “chief” in those days was the charismatic Ken-Hewitt White, who got us all involved in a Messier “hunt”.  My records show that I observed about 45 Messier objects and then abandoned the project. By then I was finished high school and starting university, and thus began a 12-year hiatus in my stargazing.  I missed some cool stuff during those years!


Even when I got back into astronomy in Halifax in the early 1980s, I did not observe the Moon, other than the odd eclipse. I did not sketch the Moon again until August 22, 2004, when I noticed the Lunar X near Werner while “tuning up” my telescope at Nova East. Observing, researching, explaining, and thinking about the Lunar X rekindled my interest in the Moon along a number of different directions. I learned that “observing” is not simply “seeing”, for one thing. It also led to an experiment in cyber-astronomy where I was able to mobilize RASC members across 5 time zones to observe and report on a phenomenon that is challenging to observe at a fixed location.  Read the full story in the file LunarX.pdf at

https://www.dropbox.com/s/vi9evo0ufwv65xc/LunarX.pdf?dl=0


A few years later, I was one of many speakers at the Nova East 2007 star party—which had a lunar theme that year—speaking about the Lunar X and listening to John Jarvo speak about the RASC’s Isabel Williamson Lunar Observing Program (https://rasc.ca/isabel-williamson-lunar-observing-program), launched in 2006. I was tempted. When I looked into it, I saw that there were roughly 150 observing objectives, some fairly easy, others a bit tougher, such as the observation of a slender moon (less than 24 hours from New Moon, either a waxing or waning crescent). I quickly surmised that this objective could potentially be a show-stopper, so I set about fulfilling that one first. The other objectives could wait! The “young Moon” observation cannot be attempted any old month: The Moon has to be close to the Sun (but not too close) yet well above the horizon (springtime is best, for waxing crescents); the sky has to be clear and free of haze; the observing location must have a low horizon (no nearby buildings or trees). With a bit of planning and a lot of luck, I snagged my young Moon (along with several other RASCals) on April 6, 2008. (The RASC Observing Committee has since relaxed the time window of this objective to 36 hours, with 24 hours as a “challenge” objective.)


With this auspicious beginning, you might expect that I would immediately launch into a disciplined program of lunar observing, to complete the objectives, but this was not the case.  I have no explanation. My observing log is practically empty for over a year following that date. I suspect IYA 2009, which kept me pretty busy “organizing” and “communicating.” At some point that fall, inspired in part by Quinn Smith (who observed all 110 Messier objects during IYA 2009) I got off my astro-butt and resumed the project. I started keeping my 8” f/6 dob in the garden shed, instead of in the basement, so ease of access might have been be a factor. I could haul it out and set it up in a couple of minutes. Both Jupiter and the Moon were high enough for me to observe from the backyard, and there many clear nights, so I made good progress.


 


The objectives for the certificate are ordered by increasing lunar longitude east to west, so once you know the longitude of the terminator on a particular date it is easy to come up with a short list of features in high relief for ease of identification. (There are several apps now that will do this for you, but at the time I had an Excel spreadsheetsupplied by an Internet friend.) At the telescope, along with the short observing list, I also had the Sky&Telescope laminated Moon chart (24” square but folds to 12” square showing a single lunar quadrant) that I picked up for $12. The observing program recommends using Antonin Rukl’s Atlas of the Moon, as a reference, but this book is out of print and hard to obtain. The laminated chart is great at the scope and the cartographer turned out to be Rukl! The chart labels most of the “mandatory” observing objectives, but only some of the “challenge” objectives in the RASC program. (There exists a “mirror-reversed” chart for telescopes with an odd number of reflecting elements.) I have found that the excellent online source


https://the-moon.us/wiki/ fills in all the gaps, as it apparently has information on all named lunar features, with links to photos and maps.


With good preparation, the time at the telescope was more relaxing. I mainly used my Discovery 8” f/6 dobsonian reflector with a 5 mm or 7 mm eyepiece for 250x and 175x, respectively. I had a Moon filter but rarely use it at these magnifications. Sometimes I used my TeleVue Ranger 70 mm f/6.8 with a 2x Barlow and the 7 mm eyepiece for 136x. My principal difficulty was the vision in my 56-year-old eyes. It just is not the same as when I was 10! I find that “floaters” interfere with the view and I need to keep moving my eyeball around to compensate.


In a given session, I tackled 6–8 objectives, which generally consisted of a group of several associated objects. In addition to craters, there are: craterlets; crater chains; central peaks and features on crater floors; single mountains, domes, and mountain ranges; ridges, rilles, and valleys; “seas”, “lakes”, and “bays”. Some objects—especially the tiny challenge objects—require 200+ power on the telescope, and on many nights the seeing does not support this. I probably spent as much time planning my session and interpreting the observations as I did observingat the telescope. There are times I had to come inside to check a detail or two. The lighting conditions on the Moon change dramatically from one night to the next, so it is sometimes necessary to observe an area more than once to tick off an objective.


I completed the program in April 2010, the 8th person to do so since its inception in 2006. As of September 2022, there are 27 recipients of the IWLOP certificate.


I enjoyed the program, visiting some old places on the Moon I recall from my first days (literally) with a telescope, but also discovering some new, interesting features I did not know about.  I would recommend it to anyone as a project, whether new to astronomy or an old hand. In 2016, RASC also introduced a simpler program for beginners, Explore the Moon (https://www.rasc.ca/observing/explore-the-moon-observing-certificate). EtM comes in both Telescope and Binocular versions, and you can earn a certificate for both. I would recommend you tackle EtM—Telescope before attempting IWLOP, unless you are an experienced observer.

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