"Sketching under changing light"
Lunar Section Report - News Circular 201 - Jan 1998
Overall, section activity since my last report has been good, and I'm pleased to say that the standard of lunar observations really has been excellent. Despite autumn's weather having been rather astro-unfriendly, and the winter so far has been truly terrible, we Moon watchers are a hardy breed and we'll take advantage of any clear break in the clouds to survey the lunar landscape - even if our observational drawings sometimes end up being half completed due to poor weather! This is a problem unique to lunar observers - any detailed observation of our lunar subject is bound to take some time to make. It requires a special dedication to apply yourself to the task of charting a small area of a lunar sea, a crater, mountain group or valley, at the same time frequently scanning the skies for signs of approaching cloud that threatens to put a swift end to our activity. A planetary disc drawing might take five or ten minutes to complete, and faint deep sky object can be recorded with the merest smudge of graphite - but the average lunar observational drawing takes at least half an hour to make. Observational drawings of the Moon are among the most difficult and time-consuming of all amateur astronomical pursuits. Yet anyone who has discovered the Moon will vouch that lunar observation is the most satisfying and visually stunning branch of amateur astronomy. As an observer myself, I can truly appreciate the hard work that section members put in.
To promote the section's work, our journal "Luna" (published since 1975) features members' observations and Moon-related articles. "Luna" is available to all SPA members and costs just 14 first class postage stamps for 4 issues (inclusive of P&P). If you wish to subscribe, please send your stamps, plus your name and address, to me at my postal address below. Those on the Internet will find the SPA Lunar Section page amid my personal homepages "Peter Grego's Cosmic Backyard" at:- http://ourworld.compuserve.com/homepages/PeterGrego. Our site includes section information and features members' lunar observations. I now also accept emailed section correspondence and observations in JPEG, TIF, GIF or BMP format (preferably 300 dpi resolution) sent to my email address at:- spa_lunar@stones.com
Grahame Wheatley of Long Eaton, Nottingham, joined us last August and has been making regular lunar observations with his 125 mm refractor. As you can see from the featured observation, Grahame's pencil drawings are beautifully made, and are both detailed and accurate. Grahame's observations include:- Theophilus area (22 Aug, 7 & 22 Sep, 7 Oct, 5 Nov); Aristarchus area (15 Aug, 13 Oct, 11 Nov); Mare Foecunditatis border (21 Aug); Julius Caesar area (8 Sep); Walter (9 Sep); Alpine Valley (9 Sep); Straight Wall (10 Sep); lunar eclipse (16 Sep); Piccolomini (21 Sep); Albategnius (23 Sep); Ptolemaeus chain (9 & 24 Sep, 7 Nov); ; Copernicus (10 Oct, 9 Nov); Gassendi (12 Sep, 12 Oct); Schickard (13 Oct); Mount Piton (22 Nov).
By making repeated observations of the same feature under different angles of illumination, Grahame is building up an intricate knowledge of each area. It is surprising how a feature can appear to change from day to day (indeed, even hour to hour when near the lunar terminator). This is the ideal way of acquiring expertise - it's hard work, but thoroughly rewarding! In Grahame's observations of Clavius (10 & 12 Sep) the changing illumination is dramatically illustrated. Clavius at sunrise is largely filled with black shadow, with only a small portion of the floor, the rims of a couple of internal craters and the far western wall catching the sunlight. Two days later, the sun has risen over Clavius. It is now mid-morning at Clavius, the Sun has risen 17° above the horizon and the whole of Clavius' floor can be seen, along with the conspicuous arc of craters that cross it. Detail can be seen in the craters Rutherford and Porter which lie on Clavius' southeast and northeast wall.
Alan Heath (who also lives in Long Eaton, Nottingham) sent in a sequential drawing of the occultation of Saturn by the Moon on 12 Nov - an event that thoroughly delighted all who stayed up into the small hours to observe. Although I saw the disappearance of Saturn, I was too busy observing Mersenius to concentrate on the reappearance of the planet (in the end, I was clouded out). My own lunar forays (using 60 mm OG, 100 mm Mak-Cass or 150 mm reflector) have included observations of le Monnier (7 Oct); Billy (14 Oct); Hortensius & domes (9 Nov); Gruithuisen area (10 Nov); Mersenius (12 Nov); Doppelmayer (10 Dec); Cauchy & rilles (2 Jan 1998); Goldschmidt (6 Jan 1998).
New member, Gordon MacLeod (Caithness, Scotland) made two line drawings of the Sinus Iridum and Jura Mountains bordering Mare Imbrium. The drawings, made on 17 Sep and 10 Dec with an 80 mm refractor, show all the main features of the region, including the craters and peaks in the mountain border and the mountains embedded in the sea to the south.
Nigel Longshaw (Oldham) continues to make exceptionally accurate and technically faultless drawings of the Moon, using pen and ink in a stippled technique - the best examples of this kind of drawing I have ever seen. With his 90 mm Mak-Cass telescope, Nigel observed:- Neander region (11 Apr); Hainzel & Mee (15 Jun) - a wonderful depiction of these features lying right on the terminator, with intricate detail in the regions protruding into the sunlight past the terminator; Phocylides; & Nasmyth (13 Oct) - his first drawing of the features since 1984, detail seen on Nasmyth's floor; Brown & E (9 Nov) - a study of these craters in the southern uplands near Tycho.
