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

Director: Bill Leatherbarrow 

The British Astronomical Association 

Lunar Section 

Circular 

Vol. 49 No. 4 April 2012 

Editor: Peter Grego 

J. Herschel, imaged by Bill Leatherbarrow on 2012 

February 2, 23:24 UT, Col. 47.0°. 12-inch MCT @ 

f/20, DMK21 mono camera. Seeing AIII. 

From the Director 

While sporadic observation of lunar surface features is both enjoyable and rewarding, there can be no doubt 

that drawings and images secured with a specific purpose in mind are usually more so. Observing the Moon 

for pleasure alone is not to be scorned, of course, but a systematic approach can sometimes yield unexpected 

and valuable results. Two examples from the March 2012 LSC will illustrate my point. 

As Nigel Longshaw points out in his article on lighting effects in Plato, that crater is one of the most 

observed and imaged features on the lunar surface, and some of the results being achieved today display 

phenomenal resolution of fine detail. However, Nigel’s careful use of both historical and modern observations 

results in an intriguing account of the unexpected appearances produced by sunrise and sunset illumination 

of Plato’s interior, one that allows us to look afresh at many of the past reports of transient phenomena in that 

region. His systematic comparison of old and new observations clearly suggests that the appearance of 

illuminated ‘tendrils’ and patches of milky ‘half-light’ is probably nothing more than the natural outcome of 

a combination of lighting, local topography, and perhaps the reflection of light onto the floor of Plato from 

brightly illuminated walls. His article gives us a clear steer for further drawings and images of Plato under 

appropriate illumination in order to check his conclusions.

It was a pleasure to see a contribution from Barry Fitz-Gerald, who was an active member of the Lunar 

Section some time ago and who has now returned to the fold. Barry’s piece on Catena Krafft shows the value 

of careful analysis of the vast repository of spacecraft imagery now available online. His view that Catena 

Krafft cannot be a secondary crater-chain originating from Krafft is undoubtedly correct, since it clearly 

impinges upon the floor and walls of that crater. The problem traditionally associated with regarding it as a 

secondary feature from Cardanus has been the fact that it is clearly not radial to Cardanus. I did wonder briefly 

whether it might be a secondary feature from Orientale, but the alignments don’t work out. Barry’s view that, 

along with the craterchain to the west with which it forms a triangle based on the N rim of Cardanus, this 

might be evidence of an oblique impact is certainly worth considering and I can think of no alternative 

account that fits the observational evidence. I am less persuaded by the suggestion that the central ridge 

crossing the floor of Alphonsus might be the result of an oblique impact that produced neighbouring Arzachel. 

The alignment of the ridge with other impact scars in the area suggests that, even if it is a deposit feature, it 

is more likely to have come from the impact that produced Imbrium. The evidence for oblique impacts on the 

Moon is growing daily (hardly surprisingly, since such impacts must have been plentiful), and there is much 

more evidence to be found both at the eyepiece and on images. 

On the question of impact ejecta, I attach an image of the crater J. Herschel, taken on 2012 February 3 

(shown on the front page). Despite the poorish seeing, what immediately struck me was the unusual nature of 

the rubbly infill that litters the crater’s interior (also shown in the LRO image below). This is presumably ejecta 

from Imbrium, and it is clear that J. Herschel took a real battering. However, although the SE half of the interior 

looks more or less as you might expect under such circumstances (apparently randomly distributed mounds and 

secondary impacts, including chains pointing back towards Imbrium), the NW half shows strange patterns in the 

distribution of ejecta material. It almost looks like martian dunes arranged in curved, arcing formation—and it 

does not appear to point a finger back at Imbrium. Moreover, there appear to be fewer secondary impact craters 

in this half. Chuck Wood has suggested that this effect is caused by the tendency of impact ejecta to ‘swirl’. 

Further analysis of existing imagery, both Earth-based and spacecraft, might help shed further light on this. 

So, plenty of things to think about and to direct our observations! 

Bill Leatherbarrow 

J. Herschel, imaged by LRO. Image: NASA / LRO LROC team. 

Director, BAA Lunar Section 

2 

BAA Lunar Section Circular Vol. 49 No. 4 April 2012

Topographical notes 

compiled by Peter Grego 

Visual studies and observations 

Since March’s LSC, visual topographic lunar observations have been received from Peter Grego (St Dennis, 

UK), Chuck Hastorf (Arizona, USA), Philip Jennings (York, UK) and Phil Morgan (Tenbury Wells, UK). 

Some of these observations and accompanying notes are reproduced below. 

A note on submitting visual observations 

All visual observations should, in the first instance, be sent to the Director, Bill Leatherbarrow, by regular 

mail or, as is far more frequently the case these days, as email image attachments (Bill’s address is on the last 

page). If possible, please copy me in on the email with the attachments at editor@baalunarsection.org.uk, as 

it saves Bill the need to send them on to me for consideration for inclusion in the LSC. 

Please note that while observations are encouraged to be posted to the Lunar Section Visual Studies 

Yahoo! Groups website http://uk.groups.yahoo.com/group/baalunarsection-topography/ it’s important not to 

regard this as the official Lunar Section archive or the primary repository for observations. The site is meant 

to be an adjunct to the main work of the Lunar Section, and serves as a forum, so please ensure that if you do 

post observations there, also to send them to the Director (and me if possible). That way, nobody’s work will 

be missed and it will be officially archived, available for comment and analysis. 

Clarity in labelling image and observation files is important, both to avoid ambiguity and confusion and 

to make filing, archiving and accessing material easier and more efficient. Ideally, all image files should 

contain unambiguous date and time data, feature observed, instrument used and observer name. Other 

information pertaining to the observation, such as colongitude and libration, should be included in the 

covering notes, along with a written description (if any) of the observation. 

Vallis Alpes and possible dome in Montes Alpes, 2012 March 29 

Philip Jennings 

The last time I sketched this region I lingered on the area for too long, resulting in inaccuracies caused by 

previously invisible features popping up half-way through the session. To avoid making the same mistake this 

time round, I drew very 

quickly. Even so, it took 

me 75 minutes to 

complete my drawing. 

Under such a low 

illumination, I couldn’t 

find an accurate template 

to help me position 

features accurately, so I 

hope it looks about right. 

The valley was looking 

spectacular, but one 

feature that caught my 

attention that evening 

was a small, circular 

‘bump’ amongst the 

mountains (arrowed), 

apparently very low. I 

doubt it would be very 

evident at all if the angle 

of illumination was 

much higher. Could this 

be a rare example of a 

highland dome 

Full Moon at perigee 

BAA Lunar Section Circular Vol. 49 No. 4 April 2012 3

John C Vetterlein 

An inspection of a table for the Moon’s perigee in 2012 reveals that the event on May 06 has our natural 

satellite at a distance of 356,955 km compared to 369,886 km on January 17. This equates to an apparent 

diameter for the Moon of 33’ 28” and 32’ 18” respectively. Interesting in itself, but when one looks more 

closely at the data for May 06 we find that Full Moon occurs within less than two minutes of perigee itself. 

This struck me at once and so I made a quick survey of the coincidence of perigee and Full Moon over a 

period of 20 years and found nothing to compare with 2012 May 6. I contacted Jean Meeus, a well known 

authority on astronomical algorithms, who supplied me with a short table of incidences of Full Moon close 

to perigee between 1972 November 20 and 2034 November 25, as shown in the following table. All times 

reduced to Universal Time (UT). 

Date Full Moon Perigee Dif. (minutes) 

1972 November 20 23:07 24:02 55 

1992 January 19 21:28 22:13 45 

2011 March 19 18:10 19:09 59 

2012 May 06 03:35 03:34 1 

2013 June 23 11:32 11:12 20 

2014 August 10 18:09 17:43 26 

2034 November 25 22:32 22:05 27 

One should state before we go any further that modern lunar theory has advanced considerably over recent 

years thereby rendering it possible to make predictions over a substantial period of time that would have been 

impossible 100 years ago. 

I decided to extend Jean’s analysis to cover the period between 1900 and 2121 (an interval of 221 years). 

Having done this I then contacted Jean again who verified my results for the most important events as follows: 

Date Full Moon Perigee Dif. (minutes.) 

1912 January 4 13:30 13:34 4 (6 min.) 

1953 September 23 04:16 04:26 10 (11 min.) 

2012 May 06 03:35 03:34 1 

2095 October 13 09:31 09:26 5 (3 min.) 

2114 December 12 06:20 06:35 15 

Figures in brackets are from Jean Meeus himself. The concordance will be seen to be very good. 

In my analysis the original table of concordances for the 221 year period amounted to over 300 entries 

with differences in the two events amounting to no more than 10 hours. The five dates given in the above 

table stood out from the rest indicating that the 2012 May 06 is exceptional by any standard. 

The fact that on 2012 

May 06 as seen from the 

UK the Moon will be in a 

twilight sky, and within 

an hour of setting, is to an 

extent unfortunate but 

insignificant compared to 

the juxtaposition of the 

two events themselves. 

I should like to thank 

Jean Meeus for his 

prompt and helpful input 

to this investigation. 

The perigee Full Moon on 

2012 May 06, 03:35 UT 

(twilight sky). 

4 


Sunrise on Plato 

Nigel Longshaw 

In the last circular I discussed sunrise on Plato and the possibility of the duality of the ‘ashen light’ previously 

observed by Phil Morgan. As an example of early sunrise on Plato a drawing by Gerald North which appeared 

in the JBAA 1986, 96, 3, was reproduced. I was pleased to subsequently receive a note from Gerald regarding 

his drawing and further discussion in relation to early sunrise on Plato. Gerald forwarded me a copy of his 

original drawing from his observing notebook, the copy I used from the original journal paper was not 

reproduced very well. It is clear from the original drawing (Figure 1) that Gerald recorded two sunlight 

‘streaks’ on the crater floor. Gerald notes the following: 

As you can see it (Figure 1) shows 

the main spire of light together 

with a shorter and dimmer one, 

which was missed out of the LSC 

reproduction. This is vaguely 

reminiscent of the CCD image in 

Tony’s piece, coincidentally about 

Plato shadows, on p19 of the LSC 

(March issue). I don’t suppose 

readers of the LSC will realise that 

mine is not a topographic 

drawing, merely a quick sketch 

showing an effect that I deemed of 

note... perhaps it would be helpful 

to supply a little of my original 

notes from my observing log: 

Figure 1. 

Telescope: 18.25-inch (464 mm) Newtonian, 2.59 m focal length. 

Date: 1981 February 12 

Time: 18h 54m - 20h 56m UT 

Magnifications: 86×, 144×, 207×, 288×, 414×, 432×, 576× 

Transparency: Poorish due to haze (limiting magnitude approx. 3.0 - 3.5) 

Turbulence: Poorish at first but becoming better during the observation period (AIII-II) 

Then I make notes on the appearances of features of the Moon against times. I will leave most of these out 

but one of relevance is: 

19h 06m UT, Change to 144×: Interior of Plato a featureless inky blackness. I carry on commenting on other 

details in this entry and then I go on to make other entries, including occasional mentions of Plato but with 

no sign of the sunrise spires until: 

20h 40m UT, 414×. Plato—two misty streaks are seen on the floor of the crater—local dawn 

20h 44m UT, 207×. Impression confirmed. Used outline chart and marked in pencil the general appearance 

on the drawing. No attempt was made to fill in other fine details. 20h 56m Markings on outline chart 

completed and after a final check observations were terminated. 

Over the drawing which is now stapled in my observing log I have written: 

Plato: 1981 February 12d, 20h 53m UT—so that is the time at which I fixed the appearance of the spires. 

(…) notice that I show the tip of the brighter spire is brighter than the rest of it—indicative of higher ground 

As to the differing historical appearances of the morning spires (or spire plus broad lighter patch), it does 

occur to me that libration in latitude could make a significant difference. Accepting that the differing angle 

of sunlight incident on the western rim and skating the interior isn’t going to vary by very much, the lighting 

situation could be critical enough to produce the variations. Indeed, from an observer positioned near the 

centre of Plato the rising point of the Sun will appear several degrees different over a large span of lunations 

thanks to libration in latitude. 

In my article I queried why Molesworth did not record the sunlight spires on his drawing of the shadowed 

interior of Plato when colongitude values suggested he should have recorded these features. Gerald responded 

with the following further comments: 


The usual figures for selenographic colongitude given in an ephemeris are defined with respect to the mean 

centre of the lunar disk (and so is 90 degrees exactly at exactly first quarter). Owing to libration in longitude, 

a feature can actually be up to 3.5 degrees either east or west of the terminator at the time when the ephemeris 

predicts that the feature should be on it. So the usual tabulated figures of selenographic colongitude only give 

the approximate position of a feature in relation to the terminator. After correcting for libration in longitude 

it might be that Molesworth really did observe earlier than the time of first appearance of the interior 

illumination of Plato. 

I am grateful to Gerald for the additional comments and the copy of his original observing notes and drawing. 

It is clear that the floor of Plato presents a number of unusual scenarios of light and shade under early sunrise 

and sunset and that the ephemeris might not tell the whole story in terms of what might be visible at the 

eyepiece. 

6 


Encke, 2012 March 03 

Peter Grego 

Notes: Further to studies of Encke made on 2009 

April 5 and 6, an observation was made with the 

crater illuminated by an earlier morning Sun. Paul 

Stephens’ 9-inch f/11 Newtonian was used—as 

the Moon was high, the observation had to be 

made atop a pair of wooden stepladders dating 

back to the 1930s that had belonged to Paul’s 

grandfather. They knew how to make things to 

last in those days—neither I nor the ladders 

creaked in the slightest. No observational 

template was used—this observational drawing is 

a PhotoPaint enhanced version of the scanned 

original telescopic pencil sketch. 

Encke is distinctly polygonal in outline. About 

half of the crater’s floor was filled with shadow 

cast by its eastern rim. Several north-south ridges 

were discerned on Encke’s floor, and the western 

floor at the base of the inner western wall was 

dark. A kink in the outline of the western rim 

marked the brightest part of the crater; this was 

the location of the crater Encke N, but it was not 

obviously crater-like in this view. The western rim 

of Encke cast a serrated shadow to the west, and 

is depicted here as it appeared shortly after the 

observation was commenced; by the end of the 

observation session, however, the shadow had 

retreated noticeably eastward but still retained all 

the original individual shadow peaks. 

The north part of crater Encke H, southwest of 

Encke, joined Encke’s shadow; it has been 

depicted a little too large here. Broad, complex 

ridges run around the eastern side of Encke; these 

have not been depicted as accurately as I had 

hoped. The ridges form the eastern wall of a larger 

crater, Encke T, in which Encke itself lies. 

2009 April 5 notes: Shadow was being cast 

by the crater’s eastern rim onto Encke’s floor; 

illuminated points within the shadow were 

located at the 1 o’clock and 5 o’clock 

positions. Some floor detail was visible in the 

form of a pronounced north-south ridge, with 

a smaller scalloped ridge to its northwest. A 

little more time would have allowed a more 

detailed study of the floor, but deteriorating 

transparency prevented this. Encke’s inner 

western wall appeared indented in a couple of 

places, at around the 9 o’ clock and 11 

o’clock positions. Wrinkle ridges ran around 

the eastern glacis of Encke, the boldest of 

them running to the south of the crater. 

BAA Lunar Section Circular Vol. 49 No. 4 April 2012 

7

The Plato ‘hook’ 

Phil Morgan 

On the evening of 2012 March 01, 18:25 UT, Col.13.1°, I was observing the Moon, but with nothing of 

particular interest on offer, I turned my attention to Plato and was struck by the sight of a particularly fine 

appearance of the famous Plato ‘hook’ effect. 

This was unexpected because I assumed that it would not be visible until the shadows had receded a bit 

more. Although the seeing was unsteady at first, when the mirror had cooled down it was quite good. 

Throughout the observing session the curve of ‘hook’ was always to the south. Just to check that this was 

indeed so I orientated myself so that the image of the Plato west facing shadows were facing down to my 

feet—that is to say that outer the western rampart was facing downwards instead of across my field of vision. 

Even with this orientation the curve of the ‘hook’ was always towards the right (southern) rampart, and those 

smaller shadows on the extreme northern half of the crater’s floor were always curving to the left (north). 

Other experienced lunar observers have also noted this hooked effect at a much greater shadow length 

than that recorded originally by Wilkins and Moore at Meudon in April 1952. 

At right (Figure 1) is an observation made by Eric 

Strach on the 1967 March 19, colongitude 13.2°, 

showing a curve of the longest shadow to the south. 

Below this at lower right (Figure 2) is an observation 

made by Roy Bridge on 1993 January 01 at 19:20 to 

20:45 UT, colongitude 12.2 to 12.9°. 184 mm spec., 

261×. This observation depicts a long shadow spire 

on the southern floor area curving slightly to the 

south. 

There will always be some differences in the 

predicted colongitude and the actual recorded 

shadow length. This is because the selenographical 

colongitude is measured from the mean centre of the 

lunar disc. Plato, being at latitude 52 degrees north, 

will always tend to be subjected to variations in its 

predicted appearance, 

due to the Moon’s 

axial tilt of 1.5 

degrees. The resulting 

swing in the Sun’s 

selenographical 

latitude could, in the 

worst-case result in a 

variation of up to plus 

or minus 4 hours’ 

difference in the 

observed shadow 

length for a given 

colongitude. Even 

with this orientation 

the ‘hook’ was always 

facing the southern 

rampart. 

Apologies for the 

poor reproduction of 

Figure 2. No higher 

resolution version 

could be found. Ed. 

Figure 2. 

Figure 1. 

8 


Join us at our Yahoo! Group: Lunar Topographic Studies 

Many more lunar observational drawings, including observations 

featured in previous Lunar Section Circulars, can be found at: 

http://uk.groups.yahoo.com/group/baalunarsection-topography/ 


Right: Detail from David 

Finnigan’s CCD image of 

Vallis Alpes (reproduced 

in its entirety overleaf), 

taken on 2012 February 

29 more than an hour 

after Phil Morgan’s 

observational drawing 

above. In the original 

image the subtle shaft of 

sunlight illuminating 

Mare Imbrium beyond the 

Montes Alpes, shown in 

Phil’s drawing, can 

clearly be seen. 

10 


Images 

Since March’s LSC, lunar imges have been received from Mike Brown (UK), Alan Clitherow (UK), Maurice 

Collins (New Zealand), Ed Crandall (USA), David Finnigan (UK), Rolf Hempel (Germany), Richard Hill 

(USA), Peter Hudson (UK), Bill Leatherbarrow (UK), Peter Oden (Germany), David Scanlan (UK), Larry 

Todd (New Zealand) and Tim Withers (UK) (not all contributors are BAA members). A selection of these 

images is featured below. My apologies to those contributors whose hard-won work is not featured in this 

issue; as usual space considerations mean that only a representative sample of material is included. 

Vallis Alpes, Aristoteles, Eudoxus. Image taken on 2012 February 29, 19:58-20:02 UT. Sun’s Col. 1.9 °, 

seeing 4/10, transparency good. 8-inch' Meade LX200 classic, f/25, DMK21AU04.AS camera, Baader IR 

pass filter. Image is a composite of 6 images: a total of 5040 frames at 30 fps processed in Registax 6, 

Paintshop Pro 8 and Serif software. Image by Dave Finnigan (Halesowen, UK). Detail below. 


(detail below) 

12 


(detail below) 


14 


Peter Oden took this detailed image of the crescent Moon on 2012 March 28. It is a composite of 50 single 

pictures (50 videos) taken with a 7-inch MCT and DMK21A04, stacked with AviStack2 und combined to 

one single photo with PaintShop. It took about two hours to take the videos, four hours to stack them and 

one more hour to combine them. Inset is a detailed study of Theophilus using the 7-inch MCT together with 

a Zeiss-Abbe-Barlow (5.4mm) and the DMK 2700mm-DMK21. 


Left: Reworked image of Mare 

Orientale by Peter Hudson, 

originally taken on 2010 

September 01 when there was a 

very favourable libration. 

Above: An LTVT simulation by 

Maurice Collins of Mare 

Orientale as it would have 

appeared on 2010 August 04 at 

10:28 UT from Palmerston 

North, New Zealand. 

The two images concur in almost 

every respect. 

16 



Transient lunar phenomena, April 2012 

Tony Cook 

Routine observations for February 2012 were received from the following observers: Jay Albert (Lake Worth, 

FL, USA) observed: Aristarchus, Bessel, Fracastorius, Kepler, Mare Crisium, Maskelyne, Plato, Proclus, 

Sabine, and Theophilus. Raffaello Braga (Italy) observed Eudoxus, Maskelyne, Maurolycus, and Proclus. 

Maurice Collins (New Zealand) took an image of Einstein and whole disk images of the Moon. Marie Cook 

(Mundesley, UK) observed: Eudoxus and Gassendi. I took time lapse video of the Moon and also took video 

of Earthshine, looking for impact flashes from Aberystwyth University. Rolf Hempel (Germany) took whole 

disk images of the Moon. Kevin Kilburn (Manchester, UK) imaged Rumker, Sinus Medii, and several 

features. Norman Izett (New Zealand) took a whole disk image of the Moon. Anthony Jennings (Manchester) 

imaged a whole disk image of the Moon. Terry King (Southwick, UK) imaged the Montes Apenninus. Nigel 

Longshaw (Olhham, UK) sketched Aristarchus. Pietre Malinski (Poland) imaged several areas of the Moon. 

Brendan Shaw (UK) imaged Arago, Aristarchus, Atlas, Censorinus, Linne, Peirce, Piazzi-Smyth, Plato, 

Poisson, Proclus, Promontorium Agarum, Ptolemaeus, and Ross D. 

News: I have received an email from Antonio Marino of the Amateur Astronomer’s Union of Naples to say 

that their group has started to actively take lunar spectra of Aristarchus, using the Capodimonte observatory 

of the National Astrophysical Institute of Naples. Using a Celestron C11 telescope and a home made 

spectroscopic equipment, they are achieving a spectroscopic scale of 0.08nm per pixel. An observational run 

on 2011Jul 12 revealed that some of the lines had a “higher spectral intensity” than the same lines on three 

later nights. Also, there was a decrease in spectral intensity of some lines down the blue end of the spectra. I 

would rather not say any more about this until they have done a ratio of spectra on different nights and 

published their results. But if I hear any more news I shall pass this onto you. 

I would like to thank Bob O’Conner for pointing out the following next two stories: 

Experimental and computer simulation research by Dutch scientists suggest that the Moon’s interior is at 

least 30% molten between 1200 and 1350 km beneath, hence the surface has been volcanically dead for some 

time now. However it could become active again in the distant future due to the way the interior melt 

crystallizes and changes buoyancy with respect to surrounding rocks—see 

www.nature.com/ngeo/journal/v5/n3/full/ngeo1402.html for further information. 

Secondly, Dr Thomas Watters from the Smithsonian Institution has been studying NASA LROC images. 

He has already found that there were plenty of examples of lobate scarps that suggest that the Moon is 

shrinking. He has now found some examples of small graben which infer that the crust is also moving apart 

in places. As some of these intersect very recent craters, this would imply that some of the graben themselves 

are very geologically young. You can see a video about this on: www.youtube.com/watchv=1Ba-9ntruCs . 

Many of these small graben are in close proximity to known Moon quake sites. This is interesting because it 

means that at least some graben could well be forming now as you read this article! A paper by Alan Binder 

in Geophysical Research Letters back in 1980 discusses the release of argon during shallow Moon quakes, so 

perhaps we have here a mechanism to kick up some dust at these sites and cause TLP Alas it seems from the 

chart of recent graben that Tom Watters shows, very few of these correlate with TLP sites. 

Routine Reports: As usual, space is rather limited to describe all of the supply of routine reports sent in, and 

the observations sent in were all of excellent quality, but here are just a few highlights from February 2012: 

1) Cauchy: On 1969 Jul 29 UT 06:00-06:22 Pamplona, and two other observers from Brazil, using a 2” 

refractor, found Cauchy to be very bright, clear and pulsating. A repeat illumination image by Norman Izett 

(New Zealand) taken on 2012 Feb 07 at 09:43 UT shows that the crater is bright, but cannot tell us if it was 

pulsating or not. For now I am leaving this TLP at a weight of 3. 

2) Bessel: On 1877 Jun 17 Dennett thought that he could detect a minute point of light shining out of the dark 

crater. Jay Albert reobserved under the same illumination conditions but could not see the claimed spot of 

light. Therefore this TLP remains at an ALPO/BAA weight of 3. 

18 


Figure 1. A modified sketch of 

Aristarchus by Nigel Longshaw 

from 2012 Feb 08, confirming the 

diffuse appearance of the interior 

of the crater at this stage in the 

illumination. North towards top. 

3) Aristarchus: On 2012 February 

08 at 23:00 UT Nigel Longshaw 

sketched Aristarchus, in the hope 

of seeing what it looked like back 

in 1983 October 22 when Peter 

Foley was supposed to have seen a 

TLP there. Nigel’s sketch indicates 

blue tint on the northern wall, a 

deep violet apron to the north and 

a diffuse bluish grey to the east. 

His sketch also depicts a bright 

extended spot on the eastern wall, 

extending beyond the crater. Here I have to apologize humbly, it seems that in my database I transposed the 

reports for 1983 Oct 22, and 23, by one day, and so Nigel’s sketch (see Figure 1) corresponds more closely 

with Geoff Amery’s TLP of 1983 Oct 22 UT 23:10 when it was reported that Aristarchus was bright and 

difficult to see detail internally, and furthermore was so bright that no measurement could be made with the 

CED (Crater Extinction Device). I have now corrected the entry in the TLP database. 

Figure 2. North is at the top. (Left) A completely shadow filled Ptolemaeus in an image by Brendan Shaw 

from 2012Feb29 UT 20:21. (Right) An ALVIS simulation of what the floor should have looked like at the 

end of the 1970 Travnik TLP. 

4) Ptolemaeus: Back in 1970Apr 14 between 00:45 and 01:30 UT Brazilian astronomer Travnik, using a 4” 

refractor, observed ‘A kind of glimmering mist lifted and wafted inside the shady hollow of the crater’. On 

2012 Feb 29 at UT 20:21 Brendan Shaw re-imaged the crater under very similar illumination conditions that 

matched to within 9 minutes the start of Travnik’s TLP. Fig 2 (left) shows what Brendan saw–it at least 

confirms that the floor was shadow filled, but shows no sign of any detail. I tried modelling the appearance 

of the floor at the end of the Travnik TLP and as Fig 2 (right) shows, we can see the raised floor breaking 

through the shadow and some characteristic shadow spires like one gets with Plato. In fact the Travnik TLP 

has some similarities to an article that I write with GLR’s Raffaello Lena in the BAA Journal Vol 114, p136- 

139 in 2004. However as we cannot completely explain the glimmering mist lifting and wafting effects 

(though these might be resolution and seeing related), I am lowering the weight of this observation to from 3 

to a 2. 


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 

20 


2012-Apr-06 UT 00:21-04:04 Ill=99% Aristarchus observed by Bartlett on 1965-09-10 and Manchester 

University: Please look for detail and colour on the floor and is the crater brighter in red, specifically at 545 

nm and 673 nm 

2012-Apr-06 UT 00:21-04:11 Ill=99% Aristarchus observed by Bartlett on 1965-09-10, LeCroy on 1976- 

02-14 and Manchester University on 1963-11-01: Please look for detail and colour on the floor, elsewhere, 

and is the crater brighter in red, specifically at 545 nm and 673 nm 

2012-Apr-06 UT 01:19-04:11 Ill=99% Copernicus observed by Manchester University astronomers on 

1963-11-01: Is the crater brighter in red, specifically at 545 nm and 673 nm 

2012-Apr-07 UT 01:05-04:35 Ill=100% Plato observed by Moore on 1980-09-24: Can you see anything 

resembling an obscuration on the NW wall or floor Any colour seen 

2012-Apr-07 UT 01:26-04:35 Ill=100% Fracastorius observed by Robinson on 1980-09-24: Any colour 

visible on the northern side Try using red and blue filters. 

2012-Apr-07 UT 02:47-04:35 Ill=100% Aristarchus observed by Moore on 1980-09-24: Can you see any 

colour on/in the crater 

2012-Apr-12 UT 04:26-05:21 Ill=64% Rimae Triesnecker observed by Markhov on 1915-07-03: Please 

image or sketch. 

2012-Apr-14 UT 04:07-05:17 Ill=42% Schroter’s Valley observed by Pickering on 1891-09-25: Please 

sketch or image. 

2012-Apr-17 UT 04:02-04:50 Ill=15% Mare Crisium observed by Arsyukhin on 1982-11-11: Please image 

or sketch in Earthshine. 

2012-Apr-23 UT PM Ill=6% Aristarchus observed by Celis on 1970-08-04: How bright is Aristarchus and 

can you see any colour in the crater in Earthshine 

2012-Apr-24 UT 21:23-22:05 Ill=11% Aristarchus observed by Celis on 1970-08-05: How bright is 

Aristarchus in Earthshine 

2012-Apr-25 UT 21:25-22:52 Ill=17% Aristarchus observed by Celis on 1970-08-06: How bright is 

Aristarchus and can you see any colour in the crater in Earthshine 

2012-Apr-25 UT 20:03-21:07 Ill=17% Please check Earthshine for sporadic meteor impact flashes. 




2012-Apr-28/29 UT 20:11-00:06 Ill=44% Picard observed by Hua on 1994-04-28: Is the rim of this crater 

dark 

2012-Apr-30 UT 19:27-20:25 Ill=65% Mons La Hire observed by Klein on 1887-02-02: Any colour or 

shadow present 

2012-Apr-30 UT 19:27-20:08 Ill=65% Plato observed by Bartlett on 1964-11-14: Any colour on the rim 

For repeat illumination (only) TLP predictions for the coming month, these can be found on the following 

web site: http://users.aber.ac.uk/atc/tlp/tlp.htm .For members who do not have access to the internet, please 

drop me a line and I will post predictions to you. If you would like to join the TLP telephone alert team, please 

let me know your phone No. and how late you wish to be contacted. If in the unlikely event you see a TLP, 

please give me a call on my cell phone: +44 (0)798 505 5681 and I will alert other observers. Note when 

telephoning from outside the UK you must not use the (0). When phoning from within the UK please do not 

use the +44! Twitter TLP alerts can be accessed on http://twitter.com/lunarnaut. 

Dr Anthony Cook, Institute of Mathematical and Physical Sciences, University of Wales Aberystwyth, 

Penglais, Aberystwyth, Ceredigion, SY23 3BZ, Wales, United Kingdom. 

Email: atc @ aber.ac.uk. 


Occultation news, April 2012 

Tim Haymes 

Double star occultation detected with video in the UK 

Alex Pratt (Leeds) reports that ZC3524, a mag. 6.9 star in Pisces which was occulted on 2011 November 06, 

was indeed a step event. Closer examination of the video by Jan Manek (IOTA total occultations regional 

coordinator for Europe) clearly indicated two stars separated in time by 11 video frames, a time difference of 

0.4 sec. The reduced light curve (see diagram) shows the fainter component disappearing first. 

Alex writes: ‘The recording was made with a Mintron video camera operating at 25 frames per second, at the 

prime focus of my 20cm aperture f/20 Maksutov-Cassegrain telescope. Embedded times accurate to 1ms were 

generated by a GPS video time inserter’. 

Right: Frame from Alex Pratt’s 

video of the occultation of 

ZC3524 on 2011 November 06. 

‘Observing conditions were not 

good. The gibbous Moon was 

86% illuminated in a hazy sky, 

with the disappearance occurring 

at a small cusp angle of 19°’. 

The recording is being analysed 

further by Brian Loader (NZ) who 

is expecting to obtain improved 

orbital data and magnitude 

differences for the double. 

Doubles listed for April are 

included with the general 

predictions for Birmingham. Observations of these are most welcome. 

22 


Graze occultations 

ZC 1198 on 2012 March 04. The coordinator attempted to observe the graze of 2B Cnc near the Aylesbury 

AS observatory (aided by the Society Chairman) but was clouded out. Gusts of wind could have been a 

problem for the planned video observation. 

ZC 1950 on 2000 Jan 27. A reduction has been recieved and this old observation will be included in the next 

Occult update. 

Occultation predictions for April 2012 

List computed for Birmingham, UK (W. Longitude 001 44 44.0, Latitude 52 27 41.0), alt. 50m, 20cm 

aperture. Event times elsewhere in the UK may differ by up to 5 min 

Occultations Co-ordinator: Tim Haymes, Hill Rise, Knowl Hill Common, Reading, RG10 9YD. 

occultation@baalunarsection.org.uk 


Lunar librations for April 2012 (from a program by J.M.H. Hill) 

24 


Lunar data for April 2012, lunations 1104/1105 (from a program by Gareth Williams) 

BAA Lunar Section Contacts 

Director 

Bill Leatherbarrow 

director@baalunarsection.org.uk 

Assistant Directors 

Tony Cook (with responsibility for TLP work) 

tlp@baalunarsection.org.uk 

Peter Grego (Circulars Editor) 

editor@baalunarsection.org.uk 

Committee Members 

Tim Haymes (Occultations) 

occultation@baalunarsection.org.uk 

Robert Garfinkle (Historical Consultant) 

history@baalunarsection.org.uk 

Bruce Kingsley (Imaging Consultant) 

photography@baalunarsection.org.uk 

Nigel Longshaw 

Brendan Shaw (Archivist) 

archives@baalunarsection.org.uk 

Computing Consultant (position vacant) 

compute@baalunarsection.org.uk 

To receive B&W printed copies of the Lunar Section 

Circular, please send a supply of stamped addressed 

envelopes to the Lunar Section Director. Envelopes at 

least 11 x 22 cm will ensure no damage in transit. 

Members who have Internet access may receive their 

Circulars (colour version) in PDF format by email 

(please contact the Director) or by downloading them 

directly from the BAA Lunar Section website at 

http://www.baalunarsection.org.uk/circulars.htm. 

BAA Lunar Section Director: Bill Leatherbarrow, 

9 Stumperlowe Avenue, Sheffield, S10 3QN, UK. 

Email: director@baalunarsection.org.uk 

Observations and items related to a specific area of 

lunar study should be sent to the appropriate member 

of the BAA Lunar Section Committee, but send any 

material of a more general nature to the Editor. 

Deadline for items for the May 2012 

Lunar Section Circular: 

15 April 2012 

Circulars Editor: Peter Grego, 7 Parc-An-Bre Drive, 

St Dennis, St Austell, Cornwall, PL26 8AS, UK. 

Email: editor@baalunarsection.org.uk

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

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