Vol 49, No 4, April 2012 - BAA Lunar Section

Figure 3. Extracts from Rolf Hempel’s image mosaic from 2012 Feb 06 with north at the top. From left to
right: Aristarchus, Menelaus, Censorinus and Proclus.
5) Aristarchus: When Sir Patrick Moore observed Aristarchus on 1983 Oct 20, at 23:40 he reported that
Aristrachus was brighter than normal (using a CED), and more so than Censorinus, Menelaus, and Proclus in
turn. On 2012 Feb 06 Rolf Hempel took a whole Moon image mosaic between 21:16 and 22:02 UT under
very similar illumination. In order of brightness here are the corresponding maximum digital number values:
Aristarchus (253), Censorinus (255), Menelaus (253) and Proclus (255). However this does not tell the whole
story as not all parts of each crater is at peak brightness. Figure 3 shows that Proclus and Censorinus appear
‘visually’ to be the brightest, or rather have more bright pixels per unit area. So for now I will leave the weight
of this observation at a 2 as it is possible that viewing angle (libration) may have some effect too.
TLP Reports: One TLP report was received: on Feb 28 at UT 19:45-20:00 Raffaello Braga (Italy, 100 mm
refractor, seeing III, transparency very good)) when he examined Maurolycus and found that the central peak
of the crater was bright in red light but disappeared in blue light. Interestingly this matched what Staedke of
Berlin saw back in 1971 May 01 under similar illumination.
Suggested Features to observe in April: For those of you without access to the internet (in the UK), below
is a list of repeat conditions for when a feature will exhibit the same illumination and libration as was seen
for a historical TLP observation from the past. By re-observing and submitting your observations, we will get
a clear understanding of what the feature ought to have looked like at the time. Only this way can we really
fully analyze past TLP reports.
2012-Apr-01 UT 18:37-20:02 Ill=70% Proclus observed by Darling on 1988-07-24: Please image or sketch.
2012-Apr-02 UT 00:17-02:39 Ill=72% Promontorium Laplace observed by Cameron on 1994-04-21: Can
you see or image any colour here
2012-Apr-02 UT 18:39-21:20 Ill=79% Proclus observed by Davis on 1988-07-25: Please sketch or image
the interior of the crater.
2012-Apr-02/03 UT 23:34-03:04 Ill=81% Posidonius observed by Dzaplashvilli on 1952-07-03: Try
observing the crater through a polaroid filter (or glasses) and rotate the filter – anything happen
2012-Apr-03 UT 18:41-19:03 Ill=88% Herodotus observed by Bartlett 1971-07-05: Any sign of pseudo peak
on the floor
2012-Apr-04 UT 19:20-22:14 Ill=94% Aristarchus observed by Bartlett on 1964-10-19: Any colour visible
on the east part of the floor
2012-Apr-04/05 UT 22:19-02:12 Ill=95% Herodotus observed by Manske on 1989-06-17: Is there a
nebulous spot near to Herodotus Is it brighter or darker in red or blue filters
2012-Apr-04/05 UT 23:01-02:51 Ill=95% Aristarchus and Copernicus observed by Scarf on 1963-10-30:
Are either of these craters brighter at 540 nm or in an orange filter than in yellow or red light
2012-Apr-05 UT 00:51-03:49 Ill=95% Schroter’s Valley observed by Louderback on 1981-11-10: Is there
any colour visible at the Cobra’s Head
2012-Apr-05/06 UT 23:32-03:28 Ill=99% Aristarchus observed by Moore on 1983-10-20: How bright is
Aristarchus compared to Censorinus, Menelaus and Proclus Which is brighter than which
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BAA Lunar Section Circular Vol. 49 No. 4 April 2012