Vol 47, No 4, April 2010 - BAA Lunar Section

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A note on Torricelli Bill Leatherbarrow This note is by way of a follow-up to Peter Grego’s fine survey of the Torricelli region, which appeared in the October 2009 issue of The New Moon (Vol. 18, No. 1). Peter mentions the debris on the floor of this crater and attributes this to slumping of the eastern wall. This is an entirely likely explanation, given the tendency for craters of this intermediate size to produce such wall slumps instead of full-scale terracing. The image above, from 1 April 2009 and taken with a 9.25-inch SCT, shows this floor material. The second image, below (20 February 2010) was taken under poorer conditions and without amplification, with an OMC300. The wider field of view offered by the lower magnification allows us to see Torricelli in the context of the impressive impact ejecta field from the larger and apparently younger crater Theophilus. (Mike Brown’s image from 8 October 2009, which accompanied Peter’s paper, also allows a fine view of this context.) These wider-field images make me wonder whether an alternative explanation for the floor debris within Torricelli might not be that it represents ejecta deposits from the impact that produced Theophilus It might be worth further study of the disposition of the debris material within Torricelli, especially under different angles of illumination. 8 BAA Lunar Section Circular Vol. 47 No. 4 April 2010
Phil notes: Another study of Alhazen Alpha under late afternoon light and a very favourable libration. I’ve also added a sequence of observations of this feature throughout the lunation to my BAA Yahoo! site photo album (see http://uk.groups.yahoo.com/group/baalunarsection-topography/). Looking through these it seems though the bands on the sunlit face of Alhazen Alpha move through the course of a lunation, and this makes me wonder if (up to a point) we are observing shadow effects Very difficult to be sure — and a set of images would be more accurate. The trouble is that the bands do not seem to show up particularly well on photos! BAA Lunar Section Circular Vol. 47 No. 4 April 2010 9
Page 1 and 2: Director: Bill Leatherbarrow The Br
Page 3 and 4: Topographical notes compiled by Pet
Page 5 and 6: largest of the group of hills to th
Page 7: Manilius and nearby dome-like eleva
Page 11 and 12: Close-up of Mike Brown’s image ab
Page 13 and 14: Rima Ariadaeus and the Julius Caesa
Page 15 and 16: LTP to be seen from Earth. They fur
Page 17 and 18: 2010-Apr-29 UT 02:52-03:40 Ill=99%
Page 19 and 20: Lunar phases April 2010 Lunar libra

Vol 47, No 4, April 2010 - BAA Lunar Section

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