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

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