Piccolomini and the Altai Mts

This region overlaps two of the section charts, namely 13 and 15.

Notes on the drawing Observation commenced with the delineation of the outline of Piccolomini, the central mountain, extent of the interior shadow and details of the inner east wall. This was followed by the careful positioning of the detached points of light beyond the terminator and, finally, the larger masses to the north before these were lost to view. After resumption at 0340 UT. the shadows thrown by the Altai scarp were drawn and also the detail on the surface to the east of these, by which time seeing had improved to 8 on my seeing scale – equivalent to Antoniadi II. By 0430 (colongitude 146°) all the smaller detached points of light to the E and NE of Piccolomini had gone except the principal masses which were now much reduced in size. A dome-like feature is indicated one diameter of Piccolomini to the west.

Despite its attraction, this region does not appear to have received much attention from amateur observers in the past to judge by the paucity of material published. Some of the smaller features shown here do not accord too well with the charts and, for this reason alone, the area might be studied profitably to clear up discordances along the lines of the old tradition.

Gauss. The walled-plain at sunset

A magnificent walled-plain, fully 110 miles in diameter at mean position 36° N 79° E which would be a most imposing object if more centrally placed. Even so, foreshortening is not so acute that interior details are difficult to make out and, when conditions are really favourable, as in the present observation, then there is much to record under good seeing with even quite moderate aperture.

Due to its size, the comparatively smooth floor shows well the curvature of the lunar globe, and, under oblique evening illumination, there is a need for haste when recording details, as noticeable changes take place in as little as 15 minutes on the rapidly darkening floor.

The main topographical features of the interior should be self-explanatory from the accompanying drawing but there was a multitude of much finer details which, although glimpsed in the better moments, could not be depicted with any certainty and which it was preferable to omit rather than indicate in a dubious representation.

The interior is commended to the interested reader who has the necessary equipment.

Mare Humboldtianum and Belkovitch

The Mare was called appropriately Humboldtianum after the explorer Alexander von Humboldt whose discoveries linked the Earth's eastern and western hemispheres. This ‘sea’ links the near and averted sides of the Moon.

The western portion of the Palus Epidemiarum

Although the Ramsden rille system was not on my observing list, the exceptional opportunity presented on 1989 January 17 as regards the seeing quality, was one not to be missed.

Shadow lengths are depicted as seen at the commencement but by the close of the observation – some two hours later – they had shortened considerably. Fine or shallow rilles which lie along, or present only a slight angle to the direction of the incident light, are not normally easy to discern owing to the lack of appreciable shadow, especially under poor or mediocre seeing. One indication of the quality of definition on this occasion was the distinctness with which the E–W rille north of the small crater Marth could be seen.

The number, identity and course of the rilles depicted show differences in some instances with those on published charts but it should be pointed out that the latter show disagreement among themselves if examined! Interested observers may, therefore, care to check what can be seen in the telescope against what is recorded here and elsewhere, always bearing in mind that in observational astronomy it is a recognised fact that everyone sees in his own way!

The crater Marth, 3.8 miles in diameter is, despite its size, a most interesting object in having a complete inner ring which is concentric to, and almost exactly half the diameter of the outer wall.

The Spitzbergen Mountains

The Spitzbergens have not received the close attention they deserve from lunarians probably because of the presence of such imposing neighbours as the well-known trio, Autolycus, Aristillus and Archimedes, which have more to offer as telescopic objects. Nevertheless, this interesting group of small bright hills are a fine spectacle under a low Sun; their mean position lies at 35° N 5° W – some 75 miles north of Archimedes. The main cluster of elevations covers some 40 miles in length from N–S with outliers further north. Some members of the group have summit craterlets but these are not visible in moderate apertures. The Spitzbergens are of no great height but they throw impressive spires of shadow at sunrise and sunset – especially at the latter as they are unimpeded by any sizeable features on the mare surface to the east. The principal spires attain a maximum projected length of 45 miles before being engulfed by the evening terminator.

The observation made on 1983 October 29, depicted in (b) and (c) is included here to show that with the value of the Sun's selenographical latitude at +1.°.02, the southernmost of the two major spires was directed towards Aristillus B, and was seen to cross the outer west glacis of that crater at colongitude 183°.2 as a grey penumbral shade – see drawing (c).

The Cichus – Weiss Region

Cichus is a well-defined crater some 25 miles in diameter situated at the southern end of the mountain barrier dividing the Palus Epidemiarum from the Mare Nubium. The surrounding walls of the crater are lofty and of the order of 8000–9000 ft above the depressed interior on which faint details can be seen under a higher light, but nothing resembling a marked central elevation. Crater A, 7 miles diameter, on the crest of the western wall of Cichus is very bright at sunrise and has a characteristic hooked aspect when seen around colongitude 20°.5.

The object of the 1983 February 21 observation was to examine the eastern section of the Hesiodus rille with particular attention to where it encounters the barrier running north from Cichus and to determine, if possible, whether its course could be traced in the interstices of the mountain range as the shadows lifted.

The region embracing the ruined formation Weiss to the NE of Cichus was also found to be one of absorbing interest and prompted the inclusion of this area in the drawing. Weiss's inner west wall showed, in addition to terracing, a banded appearance and, as the illumination proceeded, the narrow defile of a rille which runs approximately parallel to the larger Hesiodus rille, could be discerned by its penetration of the barrier.

To categorise Harold Hill as an amateur astronomer is too bland. It conveys nothing of the man who, for almost half a century, weather and leisure permitting, has assiduously charted the play of light and shade across the surface of the moon in a series of exquisite drawings. It tells even less of his eager anticipation and how his published work has encouraged and inspired moonwatchers the world over. Nor does it inform us of his approach to selenography in this age of moon landings and computer-aided telescopes. The fact is, this modest, almost self-effacing man is something of a legend. He is a living link with the golden days of moonwatching; one of the few remaining practitioners in the tradition begun by Galileo and Thomas Harriot, that includes such names as J. H. Schröter, W. G. Lohrmann, Beer and Mädler, J. F. J. Schmidt, E. Neison, T. Gwyn Elger, W. R. Birt, P. J. H. Fauth, J. N. Krieger, L. Weinek, W. Goodacre and H. P. Wilkins.

All very well it may be said. But what, other than for personal satisfaction and self-education, is the purpose of the enterprise? Why should someone spend long hours, often in great discomfort, drawing what has been photographed in great detail many times before, and at close range? So expressed, the activity assumes a certain irrelevance. And yet it has form and meaning.

This is not a guidebook to the Moon in the accepted sense, nor is it an instruction manual. It is, in effect, and as the title implies, a collection of drawings representative of various parts of the lunar surface and illustrative of different aspects of investigation which have been selected from the author's observing files covering more than 40 years.

In some respects, the choice of subjects depicted may not satisfy every reader and some may be disappointed that familiar objects such as Aristarchus, Copernicus, Plato and Theophilus, to mention a few, do not feature in these pages. This is because formations such as these were singled out for special study by earlier generations of observers. It has long been the present writer's contention that many equally deserving regions have not received anything like the same attention; accordingly he decided that some of these comparatively neglected areas should be included as warranting further study.

Not unnaturally, the present selection of some 95 regions represents features of especial interest to me, and the reader will find greater elaboration of the reasons for their selection in the notes which accompany the drawings. Suffice it to say at this point, that an early realisation that much remained to be done in mapping these wonderful landscapes led me to undertake serious lunar study almost from the commencement of my amateur observing.

Lade and its environs

One of the items on my observing programme for 1989 Feb. 12 was the examination of the enclosure designated Lade B which is situated between Godin A and the flooded Lade. It had been noticed on previous occasions that this formation bore a resemblance to a Wargentin-type structure in being filled, partially at least, with lava and as such deserving of closer study. However, lighting was insufficiently advanced on Lade B at commencement and my attention was drawn to the considerable amount of detail displayed on the interior of Lade itself – unusual in a crater in so ruinous a condition, having suffered from the effects of inundation from the south. Much finer detail was glimpsed during moments of almost perfect definition but this lay beyond the limits of resolution for a 10″ glass and no attempt was made to portray this in the drawing.

Later on, the eastern environs of Lade were observed – the most interesting feature here being a shallow valley-rille or graben running for a distance of over 50 miles in a NW–SE direction.

Beginning in the mountain ridges east of Godin A as a broad groove with raised banks, it was interrupted in its course southwards by an irregular mountain group from which it emerged much narrower and duskier along a ‘cutting’, to be blocked yet again by two hills at which it appeared to terminate, for it could be traced no further.

The starting and finishing points of astronomical calculations are usually angles, expressed as degrees, minutes and seconds of arc, or times, measured in hours, minutes, and seconds. Yet computers often cannot handle these quantities as they stand. They must first be converted to decimal degrees or hours before the computation can begin, and then the result converted back into the more-familiar minutes and seconds form. Consider, for example, the problem of finding the time corresponding to 1 hour 37 minutes before 3 : 25 in the afternoon. We first convert the times to their decimal forms, 1.616667 hours and 3.416667 hours, then subtract the former from the latter to get 1.800 hours, and finally convert back to minutes and seconds: 1 : 48 pm.

Your computer can deal with the problem of converting angles or times between decimal and minutes/seconds forms with the aid of the subroutine MINSEC. The direction in which the conversion is carried out is controlled by the switch SW(1). When SW(1) has the value +1, then the quantity represented by the input argument X (decimal degrees/hours) is converted into degrees/hours, minutes, and seconds which are returned by the output arguments XD, XM, XS respectively. XD and XM represent whole numbers while XS represents the seconds correct to two decimal places. The sign of X is returned by the string variable S$ which has the value ‘ + ’ unless X is negative when S$ becomes ‘―’. The real variable SN also carries this information since SN = +1 if X is positive, SN = 0 if X is zero, and SN = −1 if X is negative.

The prediction of the position of a planet, comet, or any other member of the Solar System, depends upon knowing its orbital elements. The orbit is completely defined by these elements (in the absence of perturbations) and hence the position of the body can be calculated for any moment in the future or the past. Sometimes, however, you may not know the elements, particularly if you have been fortunate enough to have discovered a new comet. In that case, you can measure the position of the comet on at least three separate occasions as far apart as possible and then apply one of a number of methods to deduce the set of elements which are consistent with your observations. Unfortunately, the standard methods are neither particularly easy to apply, nor to understand, so I have adopted a more obvious, if perhaps rather flat-footed, approach to the problem which makes use of the mindless number-crunching ability of a computer.

The method is best understood by first considering a simpler problem in one dimension only. Suppose that we have a mathematical relationship between the variables VO and P such that VO is a function of P i.e. given any value of P we can immediately calculate the value of VO.